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Date: Sat, 03 Mar 2018 09:27:56 -0500
From: Jeff Layton <jlayton@...hat.com>
To: Matthew Wilcox <willy@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: Matthew Wilcox <mawilcox@...rosoft.com>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v7 09/61] page cache: Use xa_lock
On Mon, 2018-02-19 at 11:45 -0800, Matthew Wilcox wrote:
> From: Matthew Wilcox <mawilcox@...rosoft.com>
>
> Remove the address_space ->tree_lock and use the xa_lock newly added to
> the radix_tree_root. Rename the address_space ->page_tree to ->pages,
> since we don't really care that it's a tree. Take the opportunity to
> rearrange the elements of address_space to pack them better on 64-bit,
> and make the comments more useful.
>
> Signed-off-by: Matthew Wilcox <mawilcox@...rosoft.com>
> ---
> Documentation/cgroup-v1/memory.txt | 2 +-
> Documentation/vm/page_migration | 14 +--
> arch/arm/include/asm/cacheflush.h | 6 +-
> arch/nios2/include/asm/cacheflush.h | 6 +-
> arch/parisc/include/asm/cacheflush.h | 6 +-
> drivers/staging/lustre/lustre/llite/glimpse.c | 2 +-
> drivers/staging/lustre/lustre/mdc/mdc_request.c | 8 +-
> fs/afs/write.c | 9 +-
> fs/btrfs/compression.c | 2 +-
> fs/btrfs/extent_io.c | 16 +--
> fs/btrfs/inode.c | 2 +-
> fs/buffer.c | 13 ++-
> fs/cifs/file.c | 9 +-
> fs/dax.c | 123 ++++++++++++------------
> fs/f2fs/data.c | 6 +-
> fs/f2fs/dir.c | 6 +-
> fs/f2fs/inline.c | 6 +-
> fs/f2fs/node.c | 8 +-
> fs/fs-writeback.c | 20 ++--
> fs/inode.c | 11 +--
> fs/nilfs2/btnode.c | 20 ++--
> fs/nilfs2/page.c | 22 ++---
> include/linux/backing-dev.h | 12 +--
> include/linux/fs.h | 17 ++--
> include/linux/mm.h | 2 +-
> include/linux/pagemap.h | 4 +-
> mm/filemap.c | 84 ++++++++--------
> mm/huge_memory.c | 10 +-
> mm/khugepaged.c | 49 +++++-----
> mm/memcontrol.c | 4 +-
> mm/migrate.c | 32 +++---
> mm/page-writeback.c | 42 ++++----
> mm/readahead.c | 2 +-
> mm/rmap.c | 4 +-
> mm/shmem.c | 60 ++++++------
> mm/swap_state.c | 17 ++--
> mm/truncate.c | 22 ++---
> mm/vmscan.c | 12 +--
> mm/workingset.c | 22 ++---
> 39 files changed, 344 insertions(+), 368 deletions(-)
>
> diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt
> index a4af2e124e24..e8ed4c2c2e9c 100644
> --- a/Documentation/cgroup-v1/memory.txt
> +++ b/Documentation/cgroup-v1/memory.txt
> @@ -262,7 +262,7 @@ When oom event notifier is registered, event will be delivered.
> 2.6 Locking
>
> lock_page_cgroup()/unlock_page_cgroup() should not be called under
> - mapping->tree_lock.
> + the mapping's xa_lock.
>
> Other lock order is following:
> PG_locked.
> diff --git a/Documentation/vm/page_migration b/Documentation/vm/page_migration
> index 0478ae2ad44a..faf849596a85 100644
> --- a/Documentation/vm/page_migration
> +++ b/Documentation/vm/page_migration
> @@ -90,7 +90,7 @@ Steps:
>
> 1. Lock the page to be migrated
>
> -2. Insure that writeback is complete.
> +2. Ensure that writeback is complete.
>
> 3. Lock the new page that we want to move to. It is locked so that accesses to
> this (not yet uptodate) page immediately lock while the move is in progress.
> @@ -100,8 +100,8 @@ Steps:
> mapcount is not zero then we do not migrate the page. All user space
> processes that attempt to access the page will now wait on the page lock.
>
> -5. The radix tree lock is taken. This will cause all processes trying
> - to access the page via the mapping to block on the radix tree spinlock.
> +5. The address space xa_lock is taken. This will cause all processes trying
> + to access the page via the mapping to block on the spinlock.
>
> 6. The refcount of the page is examined and we back out if references remain
> otherwise we know that we are the only one referencing this page.
> @@ -114,12 +114,12 @@ Steps:
>
> 9. The radix tree is changed to point to the new page.
>
> -10. The reference count of the old page is dropped because the radix tree
> +10. The reference count of the old page is dropped because the address space
> reference is gone. A reference to the new page is established because
> - the new page is referenced to by the radix tree.
> + the new page is referenced by the address space.
>
> -11. The radix tree lock is dropped. With that lookups in the mapping
> - become possible again. Processes will move from spinning on the tree_lock
> +11. The address space xa_lock is dropped. With that lookups in the mapping
> + become possible again. Processes will move from spinning on the xa_lock
> to sleeping on the locked new page.
>
> 12. The page contents are copied to the new page.
> diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
> index 74504b154256..f4ead9a74b7d 100644
> --- a/arch/arm/include/asm/cacheflush.h
> +++ b/arch/arm/include/asm/cacheflush.h
> @@ -318,10 +318,8 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
> #define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
> extern void flush_kernel_dcache_page(struct page *);
>
> -#define flush_dcache_mmap_lock(mapping) \
> - spin_lock_irq(&(mapping)->tree_lock)
> -#define flush_dcache_mmap_unlock(mapping) \
> - spin_unlock_irq(&(mapping)->tree_lock)
> +#define flush_dcache_mmap_lock(mapping) xa_lock_irq(&mapping->pages)
> +#define flush_dcache_mmap_unlock(mapping) xa_unlock_irq(&mapping->pages)
>
> #define flush_icache_user_range(vma,page,addr,len) \
> flush_dcache_page(page)
> diff --git a/arch/nios2/include/asm/cacheflush.h b/arch/nios2/include/asm/cacheflush.h
> index 55e383c173f7..7a6eda381964 100644
> --- a/arch/nios2/include/asm/cacheflush.h
> +++ b/arch/nios2/include/asm/cacheflush.h
> @@ -46,9 +46,7 @@ extern void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
> extern void flush_dcache_range(unsigned long start, unsigned long end);
> extern void invalidate_dcache_range(unsigned long start, unsigned long end);
>
> -#define flush_dcache_mmap_lock(mapping) \
> - spin_lock_irq(&(mapping)->tree_lock)
> -#define flush_dcache_mmap_unlock(mapping) \
> - spin_unlock_irq(&(mapping)->tree_lock)
> +#define flush_dcache_mmap_lock(mapping) xa_lock_irq(&mapping->pages)
> +#define flush_dcache_mmap_unlock(mapping) xa_unlock_irq(&mapping->pages)
>
> #endif /* _ASM_NIOS2_CACHEFLUSH_H */
> diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h
> index 3742508cc534..b772dd320118 100644
> --- a/arch/parisc/include/asm/cacheflush.h
> +++ b/arch/parisc/include/asm/cacheflush.h
> @@ -54,10 +54,8 @@ void invalidate_kernel_vmap_range(void *vaddr, int size);
> #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
> extern void flush_dcache_page(struct page *page);
>
> -#define flush_dcache_mmap_lock(mapping) \
> - spin_lock_irq(&(mapping)->tree_lock)
> -#define flush_dcache_mmap_unlock(mapping) \
> - spin_unlock_irq(&(mapping)->tree_lock)
> +#define flush_dcache_mmap_lock(mapping) xa_lock_irq(&mapping->pages)
> +#define flush_dcache_mmap_unlock(mapping) xa_unlock_irq(&mapping->pages)
>
> #define flush_icache_page(vma,page) do { \
> flush_kernel_dcache_page(page); \
> diff --git a/drivers/staging/lustre/lustre/llite/glimpse.c b/drivers/staging/lustre/lustre/llite/glimpse.c
> index c43ac574274c..5f2843da911c 100644
> --- a/drivers/staging/lustre/lustre/llite/glimpse.c
> +++ b/drivers/staging/lustre/lustre/llite/glimpse.c
> @@ -69,7 +69,7 @@ blkcnt_t dirty_cnt(struct inode *inode)
> void *results[1];
>
> if (inode->i_mapping)
> - cnt += radix_tree_gang_lookup_tag(&inode->i_mapping->page_tree,
> + cnt += radix_tree_gang_lookup_tag(&inode->i_mapping->pages,
> results, 0, 1,
> PAGECACHE_TAG_DIRTY);
> if (cnt == 0 && atomic_read(&vob->vob_mmap_cnt) > 0)
> diff --git a/drivers/staging/lustre/lustre/mdc/mdc_request.c b/drivers/staging/lustre/lustre/mdc/mdc_request.c
> index 03e55bca4ada..45dcf9f958d4 100644
> --- a/drivers/staging/lustre/lustre/mdc/mdc_request.c
> +++ b/drivers/staging/lustre/lustre/mdc/mdc_request.c
> @@ -937,14 +937,14 @@ static struct page *mdc_page_locate(struct address_space *mapping, __u64 *hash,
> struct page *page;
> int found;
>
> - spin_lock_irq(&mapping->tree_lock);
> - found = radix_tree_gang_lookup(&mapping->page_tree,
> + xa_lock_irq(&mapping->pages);
> + found = radix_tree_gang_lookup(&mapping->pages,
> (void **)&page, offset, 1);
> if (found > 0 && !radix_tree_exceptional_entry(page)) {
> struct lu_dirpage *dp;
>
> get_page(page);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> /*
> * In contrast to find_lock_page() we are sure that directory
> * page cannot be truncated (while DLM lock is held) and,
> @@ -992,7 +992,7 @@ static struct page *mdc_page_locate(struct address_space *mapping, __u64 *hash,
> page = ERR_PTR(-EIO);
> }
> } else {
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> page = NULL;
> }
> return page;
> diff --git a/fs/afs/write.c b/fs/afs/write.c
> index 9370e2feb999..603d2ce48dbb 100644
> --- a/fs/afs/write.c
> +++ b/fs/afs/write.c
> @@ -570,10 +570,11 @@ static int afs_writepages_region(struct address_space *mapping,
>
> _debug("wback %lx", page->index);
>
> - /* at this point we hold neither mapping->tree_lock nor lock on
> - * the page itself: the page may be truncated or invalidated
> - * (changing page->mapping to NULL), or even swizzled back from
> - * swapper_space to tmpfs file mapping
> + /*
> + * at this point we hold neither the xa_lock nor the
> + * page lock: the page may be truncated or invalidated
> + * (changing page->mapping to NULL), or even swizzled
> + * back from swapper_space to tmpfs file mapping
> */
> ret = lock_page_killable(page);
> if (ret < 0) {
> diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
> index 07d049c0c20f..0e35aa6aa2f1 100644
> --- a/fs/btrfs/compression.c
> +++ b/fs/btrfs/compression.c
> @@ -458,7 +458,7 @@ static noinline int add_ra_bio_pages(struct inode *inode,
> break;
>
> rcu_read_lock();
> - page = radix_tree_lookup(&mapping->page_tree, pg_index);
> + page = radix_tree_lookup(&mapping->pages, pg_index);
> rcu_read_unlock();
> if (page && !radix_tree_exceptional_entry(page)) {
> misses++;
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index dfeb74a0be77..1f2739702518 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -3958,11 +3958,11 @@ static int extent_write_cache_pages(struct address_space *mapping,
>
> done_index = page->index;
> /*
> - * At this point we hold neither mapping->tree_lock nor
> - * lock on the page itself: the page may be truncated or
> - * invalidated (changing page->mapping to NULL), or even
> - * swizzled back from swapper_space to tmpfs file
> - * mapping
> + * At this point we hold neither the xa_lock nor
> + * the page lock: the page may be truncated or
> + * invalidated (changing page->mapping to NULL),
> + * or even swizzled back from swapper_space to
> + * tmpfs file mapping
> */
> if (!trylock_page(page)) {
> flush_write_bio(epd);
> @@ -5169,13 +5169,13 @@ void clear_extent_buffer_dirty(struct extent_buffer *eb)
> WARN_ON(!PagePrivate(page));
>
> clear_page_dirty_for_io(page);
> - spin_lock_irq(&page->mapping->tree_lock);
> + xa_lock_irq(&page->mapping->pages);
> if (!PageDirty(page)) {
> - radix_tree_tag_clear(&page->mapping->page_tree,
> + radix_tree_tag_clear(&page->mapping->pages,
> page_index(page),
> PAGECACHE_TAG_DIRTY);
> }
> - spin_unlock_irq(&page->mapping->tree_lock);
> + xa_unlock_irq(&page->mapping->pages);
> ClearPageError(page);
> unlock_page(page);
> }
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 53ca025655fc..d0016c1c7b04 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -7427,7 +7427,7 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
>
> bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
> {
> - struct radix_tree_root *root = &inode->i_mapping->page_tree;
> + struct radix_tree_root *root = &inode->i_mapping->pages;
> bool found = false;
> void **pagep = NULL;
> struct page *page = NULL;
> diff --git a/fs/buffer.c b/fs/buffer.c
> index 0b487cdb7124..692ee249fb6a 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -185,10 +185,9 @@ EXPORT_SYMBOL(end_buffer_write_sync);
> * we get exclusion from try_to_free_buffers with the blockdev mapping's
> * private_lock.
> *
> - * Hack idea: for the blockdev mapping, i_bufferlist_lock contention
> + * Hack idea: for the blockdev mapping, private_lock contention
> * may be quite high. This code could TryLock the page, and if that
> - * succeeds, there is no need to take private_lock. (But if
> - * private_lock is contended then so is mapping->tree_lock).
> + * succeeds, there is no need to take private_lock.
> */
> static struct buffer_head *
> __find_get_block_slow(struct block_device *bdev, sector_t block)
> @@ -599,14 +598,14 @@ void __set_page_dirty(struct page *page, struct address_space *mapping,
> {
> unsigned long flags;
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> if (page->mapping) { /* Race with truncate? */
> WARN_ON_ONCE(warn && !PageUptodate(page));
> account_page_dirtied(page, mapping);
> - radix_tree_tag_set(&mapping->page_tree,
> + radix_tree_tag_set(&mapping->pages,
> page_index(page), PAGECACHE_TAG_DIRTY);
> }
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> }
> EXPORT_SYMBOL_GPL(__set_page_dirty);
>
> @@ -1096,7 +1095,7 @@ __getblk_slow(struct block_device *bdev, sector_t block,
> * inode list.
> *
> * mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock,
> - * mapping->tree_lock and mapping->host->i_lock.
> + * mapping xa_lock and mapping->host->i_lock.
> */
> void mark_buffer_dirty(struct buffer_head *bh)
> {
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 7cee97b93a61..a6ace9ac4d94 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -1987,11 +1987,10 @@ wdata_prepare_pages(struct cifs_writedata *wdata, unsigned int found_pages,
> for (i = 0; i < found_pages; i++) {
> page = wdata->pages[i];
> /*
> - * At this point we hold neither mapping->tree_lock nor
> - * lock on the page itself: the page may be truncated or
> - * invalidated (changing page->mapping to NULL), or even
> - * swizzled back from swapper_space to tmpfs file
> - * mapping
> + * At this point we hold neither the xa_lock nor the
> + * page lock: the page may be truncated or invalidated
> + * (changing page->mapping to NULL), or even swizzled
> + * back from swapper_space to tmpfs file mapping
> */
>
> if (nr_pages == 0)
> diff --git a/fs/dax.c b/fs/dax.c
> index 0276df90e86c..cac580399ed4 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -159,11 +159,9 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo
> }
>
> /*
> - * We do not necessarily hold the mapping->tree_lock when we call this
> - * function so it is possible that 'entry' is no longer a valid item in the
> - * radix tree. This is okay because all we really need to do is to find the
> - * correct waitqueue where tasks might be waiting for that old 'entry' and
> - * wake them.
> + * @entry may no longer be the entry at the index in the mapping.
> + * The important information it's conveying is whether the entry at
> + * this index used to be a PMD entry.
> */
> static void dax_wake_mapping_entry_waiter(struct address_space *mapping,
> pgoff_t index, void *entry, bool wake_all)
> @@ -175,7 +173,7 @@ static void dax_wake_mapping_entry_waiter(struct address_space *mapping,
>
> /*
> * Checking for locked entry and prepare_to_wait_exclusive() happens
> - * under mapping->tree_lock, ditto for entry handling in our callers.
> + * under xa_lock, ditto for entry handling in our callers.
> * So at this point all tasks that could have seen our entry locked
> * must be in the waitqueue and the following check will see them.
> */
> @@ -184,41 +182,38 @@ static void dax_wake_mapping_entry_waiter(struct address_space *mapping,
> }
>
> /*
> - * Check whether the given slot is locked. The function must be called with
> - * mapping->tree_lock held
> + * Check whether the given slot is locked. Must be called with xa_lock held.
> */
> static inline int slot_locked(struct address_space *mapping, void **slot)
> {
> unsigned long entry = (unsigned long)
> - radix_tree_deref_slot_protected(slot, &mapping->tree_lock);
> + radix_tree_deref_slot_protected(slot, &mapping->pages.xa_lock);
> return entry & RADIX_DAX_ENTRY_LOCK;
> }
>
> /*
> - * Mark the given slot is locked. The function must be called with
> - * mapping->tree_lock held
> + * Mark the given slot as locked. Must be called with xa_lock held.
> */
> static inline void *lock_slot(struct address_space *mapping, void **slot)
> {
> unsigned long entry = (unsigned long)
> - radix_tree_deref_slot_protected(slot, &mapping->tree_lock);
> + radix_tree_deref_slot_protected(slot, &mapping->pages.xa_lock);
>
> entry |= RADIX_DAX_ENTRY_LOCK;
> - radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry);
> + radix_tree_replace_slot(&mapping->pages, slot, (void *)entry);
> return (void *)entry;
> }
>
> /*
> - * Mark the given slot is unlocked. The function must be called with
> - * mapping->tree_lock held
> + * Mark the given slot as unlocked. Must be called with xa_lock held.
> */
> static inline void *unlock_slot(struct address_space *mapping, void **slot)
> {
> unsigned long entry = (unsigned long)
> - radix_tree_deref_slot_protected(slot, &mapping->tree_lock);
> + radix_tree_deref_slot_protected(slot, &mapping->pages.xa_lock);
>
> entry &= ~(unsigned long)RADIX_DAX_ENTRY_LOCK;
> - radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry);
> + radix_tree_replace_slot(&mapping->pages, slot, (void *)entry);
> return (void *)entry;
> }
>
> @@ -229,7 +224,7 @@ static inline void *unlock_slot(struct address_space *mapping, void **slot)
> * put_locked_mapping_entry() when he locked the entry and now wants to
> * unlock it.
> *
> - * The function must be called with mapping->tree_lock held.
> + * Must be called with xa_lock held.
> */
> static void *get_unlocked_mapping_entry(struct address_space *mapping,
> pgoff_t index, void ***slotp)
> @@ -242,7 +237,7 @@ static void *get_unlocked_mapping_entry(struct address_space *mapping,
> ewait.wait.func = wake_exceptional_entry_func;
>
> for (;;) {
> - entry = __radix_tree_lookup(&mapping->page_tree, index, NULL,
> + entry = __radix_tree_lookup(&mapping->pages, index, NULL,
> &slot);
> if (!entry ||
> WARN_ON_ONCE(!radix_tree_exceptional_entry(entry)) ||
> @@ -255,10 +250,10 @@ static void *get_unlocked_mapping_entry(struct address_space *mapping,
> wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key);
> prepare_to_wait_exclusive(wq, &ewait.wait,
> TASK_UNINTERRUPTIBLE);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> schedule();
> finish_wait(wq, &ewait.wait);
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> }
> }
>
> @@ -267,15 +262,15 @@ static void dax_unlock_mapping_entry(struct address_space *mapping,
> {
> void *entry, **slot;
>
> - spin_lock_irq(&mapping->tree_lock);
> - entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot);
> + xa_lock_irq(&mapping->pages);
> + entry = __radix_tree_lookup(&mapping->pages, index, NULL, &slot);
> if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) ||
> !slot_locked(mapping, slot))) {
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return;
> }
> unlock_slot(mapping, slot);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> dax_wake_mapping_entry_waiter(mapping, index, entry, false);
> }
>
> @@ -332,7 +327,7 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
> void *entry, **slot;
>
> restart:
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> entry = get_unlocked_mapping_entry(mapping, index, &slot);
>
> if (WARN_ON_ONCE(entry && !radix_tree_exceptional_entry(entry))) {
> @@ -364,12 +359,12 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
> if (pmd_downgrade) {
> /*
> * Make sure 'entry' remains valid while we drop
> - * mapping->tree_lock.
> + * xa_lock.
> */
> entry = lock_slot(mapping, slot);
> }
>
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> /*
> * Besides huge zero pages the only other thing that gets
> * downgraded are empty entries which don't need to be
> @@ -386,26 +381,26 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
> put_locked_mapping_entry(mapping, index);
> return ERR_PTR(err);
> }
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
>
> if (!entry) {
> /*
> - * We needed to drop the page_tree lock while calling
> + * We needed to drop the pages lock while calling
> * radix_tree_preload() and we didn't have an entry to
> * lock. See if another thread inserted an entry at
> * our index during this time.
> */
> - entry = __radix_tree_lookup(&mapping->page_tree, index,
> + entry = __radix_tree_lookup(&mapping->pages, index,
> NULL, &slot);
> if (entry) {
> radix_tree_preload_end();
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> goto restart;
> }
> }
>
> if (pmd_downgrade) {
> - radix_tree_delete(&mapping->page_tree, index);
> + radix_tree_delete(&mapping->pages, index);
> mapping->nrexceptional--;
> dax_wake_mapping_entry_waiter(mapping, index, entry,
> true);
> @@ -413,11 +408,11 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
>
> entry = dax_radix_locked_entry(0, size_flag | RADIX_DAX_EMPTY);
>
> - err = __radix_tree_insert(&mapping->page_tree, index,
> + err = __radix_tree_insert(&mapping->pages, index,
> dax_radix_order(entry), entry);
> radix_tree_preload_end();
> if (err) {
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> /*
> * Our insertion of a DAX entry failed, most likely
> * because we were inserting a PMD entry and it
> @@ -430,12 +425,12 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
> }
> /* Good, we have inserted empty locked entry into the tree. */
> mapping->nrexceptional++;
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return entry;
> }
> entry = lock_slot(mapping, slot);
> out_unlock:
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return entry;
> }
>
> @@ -444,22 +439,22 @@ static int __dax_invalidate_mapping_entry(struct address_space *mapping,
> {
> int ret = 0;
> void *entry;
> - struct radix_tree_root *page_tree = &mapping->page_tree;
> + struct radix_tree_root *pages = &mapping->pages;
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> entry = get_unlocked_mapping_entry(mapping, index, NULL);
> if (!entry || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry)))
> goto out;
> if (!trunc &&
> - (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) ||
> - radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)))
> + (radix_tree_tag_get(pages, index, PAGECACHE_TAG_DIRTY) ||
> + radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE)))
> goto out;
> - radix_tree_delete(page_tree, index);
> + radix_tree_delete(pages, index);
> mapping->nrexceptional--;
> ret = 1;
> out:
> put_unlocked_mapping_entry(mapping, index, entry);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return ret;
> }
> /*
> @@ -529,7 +524,7 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
> void *entry, sector_t sector,
> unsigned long flags, bool dirty)
> {
> - struct radix_tree_root *page_tree = &mapping->page_tree;
> + struct radix_tree_root *pages = &mapping->pages;
> void *new_entry;
> pgoff_t index = vmf->pgoff;
>
> @@ -545,7 +540,7 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
> unmap_mapping_pages(mapping, vmf->pgoff, 1, false);
> }
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> new_entry = dax_radix_locked_entry(sector, flags);
>
> if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
> @@ -561,17 +556,17 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
> void **slot;
> void *ret;
>
> - ret = __radix_tree_lookup(page_tree, index, &node, &slot);
> + ret = __radix_tree_lookup(pages, index, &node, &slot);
> WARN_ON_ONCE(ret != entry);
> - __radix_tree_replace(page_tree, node, slot,
> + __radix_tree_replace(pages, node, slot,
> new_entry, NULL);
> entry = new_entry;
> }
>
> if (dirty)
> - radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY);
> + radix_tree_tag_set(pages, index, PAGECACHE_TAG_DIRTY);
>
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return entry;
> }
>
> @@ -661,7 +656,7 @@ static int dax_writeback_one(struct block_device *bdev,
> struct dax_device *dax_dev, struct address_space *mapping,
> pgoff_t index, void *entry)
> {
> - struct radix_tree_root *page_tree = &mapping->page_tree;
> + struct radix_tree_root *pages = &mapping->pages;
> void *entry2, **slot, *kaddr;
> long ret = 0, id;
> sector_t sector;
> @@ -676,7 +671,7 @@ static int dax_writeback_one(struct block_device *bdev,
> if (WARN_ON(!radix_tree_exceptional_entry(entry)))
> return -EIO;
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> entry2 = get_unlocked_mapping_entry(mapping, index, &slot);
> /* Entry got punched out / reallocated? */
> if (!entry2 || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry2)))
> @@ -695,7 +690,7 @@ static int dax_writeback_one(struct block_device *bdev,
> }
>
> /* Another fsync thread may have already written back this entry */
> - if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))
> + if (!radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE))
> goto put_unlocked;
> /* Lock the entry to serialize with page faults */
> entry = lock_slot(mapping, slot);
> @@ -703,11 +698,11 @@ static int dax_writeback_one(struct block_device *bdev,
> * We can clear the tag now but we have to be careful so that concurrent
> * dax_writeback_one() calls for the same index cannot finish before we
> * actually flush the caches. This is achieved as the calls will look
> - * at the entry only under tree_lock and once they do that they will
> + * at the entry only under xa_lock and once they do that they will
> * see the entry locked and wait for it to unlock.
> */
> - radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE);
> - spin_unlock_irq(&mapping->tree_lock);
> + radix_tree_tag_clear(pages, index, PAGECACHE_TAG_TOWRITE);
> + xa_unlock_irq(&mapping->pages);
>
> /*
> * Even if dax_writeback_mapping_range() was given a wbc->range_start
> @@ -725,7 +720,7 @@ static int dax_writeback_one(struct block_device *bdev,
> goto dax_unlock;
>
> /*
> - * dax_direct_access() may sleep, so cannot hold tree_lock over
> + * dax_direct_access() may sleep, so cannot hold xa_lock over
> * its invocation.
> */
> ret = dax_direct_access(dax_dev, pgoff, size / PAGE_SIZE, &kaddr, &pfn);
> @@ -745,9 +740,9 @@ static int dax_writeback_one(struct block_device *bdev,
> * the pfn mappings are writeprotected and fault waits for mapping
> * entry lock.
> */
> - spin_lock_irq(&mapping->tree_lock);
> - radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> + radix_tree_tag_clear(pages, index, PAGECACHE_TAG_DIRTY);
> + xa_unlock_irq(&mapping->pages);
> trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT);
> dax_unlock:
> dax_read_unlock(id);
> @@ -756,7 +751,7 @@ static int dax_writeback_one(struct block_device *bdev,
>
> put_unlocked:
> put_unlocked_mapping_entry(mapping, index, entry2);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return ret;
> }
>
> @@ -1524,21 +1519,21 @@ static int dax_insert_pfn_mkwrite(struct vm_fault *vmf,
> pgoff_t index = vmf->pgoff;
> int vmf_ret, error;
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> entry = get_unlocked_mapping_entry(mapping, index, &slot);
> /* Did we race with someone splitting entry or so? */
> if (!entry ||
> (pe_size == PE_SIZE_PTE && !dax_is_pte_entry(entry)) ||
> (pe_size == PE_SIZE_PMD && !dax_is_pmd_entry(entry))) {
> put_unlocked_mapping_entry(mapping, index, entry);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf,
> VM_FAULT_NOPAGE);
> return VM_FAULT_NOPAGE;
> }
> - radix_tree_tag_set(&mapping->page_tree, index, PAGECACHE_TAG_DIRTY);
> + radix_tree_tag_set(&mapping->pages, index, PAGECACHE_TAG_DIRTY);
> entry = lock_slot(mapping, slot);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> switch (pe_size) {
> case PE_SIZE_PTE:
> error = vm_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 7578ed1a85e0..4eee39befc67 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2381,12 +2381,12 @@ void f2fs_set_page_dirty_nobuffers(struct page *page)
> SetPageDirty(page);
> spin_unlock(&mapping->private_lock);
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> WARN_ON_ONCE(!PageUptodate(page));
> account_page_dirtied(page, mapping);
> - radix_tree_tag_set(&mapping->page_tree,
> + radix_tree_tag_set(&mapping->pages,
> page_index(page), PAGECACHE_TAG_DIRTY);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> unlock_page_memcg(page);
>
> __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index f00b5ed8c011..0fd9695eddf6 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -741,10 +741,10 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
>
> if (bit_pos == NR_DENTRY_IN_BLOCK &&
> !truncate_hole(dir, page->index, page->index + 1)) {
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> - radix_tree_tag_clear(&mapping->page_tree, page_index(page),
> + xa_lock_irqsave(&mapping->pages, flags);
> + radix_tree_tag_clear(&mapping->pages, page_index(page),
> PAGECACHE_TAG_DIRTY);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
>
> clear_page_dirty_for_io(page);
> ClearPagePrivate(page);
> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> index 90e38d8ea688..7858b8e15f33 100644
> --- a/fs/f2fs/inline.c
> +++ b/fs/f2fs/inline.c
> @@ -226,10 +226,10 @@ int f2fs_write_inline_data(struct inode *inode, struct page *page)
> kunmap_atomic(src_addr);
> set_page_dirty(dn.inode_page);
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> - radix_tree_tag_clear(&mapping->page_tree, page_index(page),
> + xa_lock_irqsave(&mapping->pages, flags);
> + radix_tree_tag_clear(&mapping->pages, page_index(page),
> PAGECACHE_TAG_DIRTY);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
>
> set_inode_flag(inode, FI_APPEND_WRITE);
> set_inode_flag(inode, FI_DATA_EXIST);
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 177c438e4a56..fba2644abdf0 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -91,11 +91,11 @@ static void clear_node_page_dirty(struct page *page)
> unsigned int long flags;
>
> if (PageDirty(page)) {
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> - radix_tree_tag_clear(&mapping->page_tree,
> + xa_lock_irqsave(&mapping->pages, flags);
> + radix_tree_tag_clear(&mapping->pages,
> page_index(page),
> PAGECACHE_TAG_DIRTY);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
>
> clear_page_dirty_for_io(page);
> dec_page_count(F2FS_M_SB(mapping), F2FS_DIRTY_NODES);
> @@ -1140,7 +1140,7 @@ void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
> f2fs_bug_on(sbi, check_nid_range(sbi, nid));
>
> rcu_read_lock();
> - apage = radix_tree_lookup(&NODE_MAPPING(sbi)->page_tree, nid);
> + apage = radix_tree_lookup(&NODE_MAPPING(sbi)->pages, nid);
> rcu_read_unlock();
> if (apage)
> return;
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index d4d04fee568a..d5c0e70dbfa8 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -347,9 +347,9 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
> * By the time control reaches here, RCU grace period has passed
> * since I_WB_SWITCH assertion and all wb stat update transactions
> * between unlocked_inode_to_wb_begin/end() are guaranteed to be
> - * synchronizing against mapping->tree_lock.
> + * synchronizing against xa_lock.
> *
> - * Grabbing old_wb->list_lock, inode->i_lock and mapping->tree_lock
> + * Grabbing old_wb->list_lock, inode->i_lock and xa_lock
> * gives us exclusion against all wb related operations on @inode
> * including IO list manipulations and stat updates.
> */
> @@ -361,7 +361,7 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
> spin_lock_nested(&old_wb->list_lock, SINGLE_DEPTH_NESTING);
> }
> spin_lock(&inode->i_lock);
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
>
> /*
> * Once I_FREEING is visible under i_lock, the eviction path owns
> @@ -373,22 +373,22 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
> /*
> * Count and transfer stats. Note that PAGECACHE_TAG_DIRTY points
> * to possibly dirty pages while PAGECACHE_TAG_WRITEBACK points to
> - * pages actually under underwriteback.
> + * pages actually under writeback.
> */
> - radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, 0,
> + radix_tree_for_each_tagged(slot, &mapping->pages, &iter, 0,
> PAGECACHE_TAG_DIRTY) {
> struct page *page = radix_tree_deref_slot_protected(slot,
> - &mapping->tree_lock);
> + &mapping->pages.xa_lock);
> if (likely(page) && PageDirty(page)) {
> dec_wb_stat(old_wb, WB_RECLAIMABLE);
> inc_wb_stat(new_wb, WB_RECLAIMABLE);
> }
> }
>
> - radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, 0,
> + radix_tree_for_each_tagged(slot, &mapping->pages, &iter, 0,
> PAGECACHE_TAG_WRITEBACK) {
> struct page *page = radix_tree_deref_slot_protected(slot,
> - &mapping->tree_lock);
> + &mapping->pages.xa_lock);
> if (likely(page)) {
> WARN_ON_ONCE(!PageWriteback(page));
> dec_wb_stat(old_wb, WB_WRITEBACK);
> @@ -430,7 +430,7 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
> */
> smp_store_release(&inode->i_state, inode->i_state & ~I_WB_SWITCH);
>
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> spin_unlock(&inode->i_lock);
> spin_unlock(&new_wb->list_lock);
> spin_unlock(&old_wb->list_lock);
> @@ -507,7 +507,7 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id)
> /*
> * In addition to synchronizing among switchers, I_WB_SWITCH tells
> * the RCU protected stat update paths to grab the mapping's
> - * tree_lock so that stat transfer can synchronize against them.
> + * xa_lock so that stat transfer can synchronize against them.
> * Let's continue after I_WB_SWITCH is guaranteed to be visible.
> */
> call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn);
> diff --git a/fs/inode.c b/fs/inode.c
> index ef362364d396..07e26909e24d 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -349,8 +349,7 @@ EXPORT_SYMBOL(inc_nlink);
> void address_space_init_once(struct address_space *mapping)
> {
> memset(mapping, 0, sizeof(*mapping));
> - INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC | __GFP_ACCOUNT);
> - spin_lock_init(&mapping->tree_lock);
> + INIT_RADIX_TREE(&mapping->pages, GFP_ATOMIC | __GFP_ACCOUNT);
> init_rwsem(&mapping->i_mmap_rwsem);
> INIT_LIST_HEAD(&mapping->private_list);
> spin_lock_init(&mapping->private_lock);
> @@ -499,14 +498,14 @@ EXPORT_SYMBOL(__remove_inode_hash);
> void clear_inode(struct inode *inode)
> {
> /*
> - * We have to cycle tree_lock here because reclaim can be still in the
> + * We have to cycle the xa_lock here because reclaim can be in the
> * process of removing the last page (in __delete_from_page_cache())
> - * and we must not free mapping under it.
> + * and we must not free the mapping under it.
> */
> - spin_lock_irq(&inode->i_data.tree_lock);
> + xa_lock_irq(&inode->i_data.pages);
> BUG_ON(inode->i_data.nrpages);
> BUG_ON(inode->i_data.nrexceptional);
> - spin_unlock_irq(&inode->i_data.tree_lock);
> + xa_unlock_irq(&inode->i_data.pages);
> BUG_ON(!list_empty(&inode->i_data.private_list));
> BUG_ON(!(inode->i_state & I_FREEING));
> BUG_ON(inode->i_state & I_CLEAR);
> diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c
> index c21e0b4454a6..9e2a00207436 100644
> --- a/fs/nilfs2/btnode.c
> +++ b/fs/nilfs2/btnode.c
> @@ -193,9 +193,9 @@ int nilfs_btnode_prepare_change_key(struct address_space *btnc,
> (unsigned long long)oldkey,
> (unsigned long long)newkey);
>
> - spin_lock_irq(&btnc->tree_lock);
> - err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
> - spin_unlock_irq(&btnc->tree_lock);
> + xa_lock_irq(&btnc->pages);
> + err = radix_tree_insert(&btnc->pages, newkey, obh->b_page);
> + xa_unlock_irq(&btnc->pages);
> /*
> * Note: page->index will not change to newkey until
> * nilfs_btnode_commit_change_key() will be called.
> @@ -251,11 +251,11 @@ void nilfs_btnode_commit_change_key(struct address_space *btnc,
> (unsigned long long)newkey);
> mark_buffer_dirty(obh);
>
> - spin_lock_irq(&btnc->tree_lock);
> - radix_tree_delete(&btnc->page_tree, oldkey);
> - radix_tree_tag_set(&btnc->page_tree, newkey,
> + xa_lock_irq(&btnc->pages);
> + radix_tree_delete(&btnc->pages, oldkey);
> + radix_tree_tag_set(&btnc->pages, newkey,
> PAGECACHE_TAG_DIRTY);
> - spin_unlock_irq(&btnc->tree_lock);
> + xa_unlock_irq(&btnc->pages);
>
> opage->index = obh->b_blocknr = newkey;
> unlock_page(opage);
> @@ -283,9 +283,9 @@ void nilfs_btnode_abort_change_key(struct address_space *btnc,
> return;
>
> if (nbh == NULL) { /* blocksize == pagesize */
> - spin_lock_irq(&btnc->tree_lock);
> - radix_tree_delete(&btnc->page_tree, newkey);
> - spin_unlock_irq(&btnc->tree_lock);
> + xa_lock_irq(&btnc->pages);
> + radix_tree_delete(&btnc->pages, newkey);
> + xa_unlock_irq(&btnc->pages);
> unlock_page(ctxt->bh->b_page);
> } else
> brelse(nbh);
> diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
> index 68241512d7c1..1c6703efde9e 100644
> --- a/fs/nilfs2/page.c
> +++ b/fs/nilfs2/page.c
> @@ -331,15 +331,15 @@ void nilfs_copy_back_pages(struct address_space *dmap,
> struct page *page2;
>
> /* move the page to the destination cache */
> - spin_lock_irq(&smap->tree_lock);
> - page2 = radix_tree_delete(&smap->page_tree, offset);
> + xa_lock_irq(&smap->pages);
> + page2 = radix_tree_delete(&smap->pages, offset);
> WARN_ON(page2 != page);
>
> smap->nrpages--;
> - spin_unlock_irq(&smap->tree_lock);
> + xa_unlock_irq(&smap->pages);
>
> - spin_lock_irq(&dmap->tree_lock);
> - err = radix_tree_insert(&dmap->page_tree, offset, page);
> + xa_lock_irq(&dmap->pages);
> + err = radix_tree_insert(&dmap->pages, offset, page);
> if (unlikely(err < 0)) {
> WARN_ON(err == -EEXIST);
> page->mapping = NULL;
> @@ -348,11 +348,11 @@ void nilfs_copy_back_pages(struct address_space *dmap,
> page->mapping = dmap;
> dmap->nrpages++;
> if (PageDirty(page))
> - radix_tree_tag_set(&dmap->page_tree,
> + radix_tree_tag_set(&dmap->pages,
> offset,
> PAGECACHE_TAG_DIRTY);
> }
> - spin_unlock_irq(&dmap->tree_lock);
> + xa_unlock_irq(&dmap->pages);
> }
> unlock_page(page);
> }
> @@ -474,15 +474,15 @@ int __nilfs_clear_page_dirty(struct page *page)
> struct address_space *mapping = page->mapping;
>
> if (mapping) {
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> if (test_bit(PG_dirty, &page->flags)) {
> - radix_tree_tag_clear(&mapping->page_tree,
> + radix_tree_tag_clear(&mapping->pages,
> page_index(page),
> PAGECACHE_TAG_DIRTY);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return clear_page_dirty_for_io(page);
> }
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return 0;
> }
> return TestClearPageDirty(page);
> diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
> index 3e4ce54d84ab..3df0d20e23f3 100644
> --- a/include/linux/backing-dev.h
> +++ b/include/linux/backing-dev.h
> @@ -329,7 +329,7 @@ static inline bool inode_to_wb_is_valid(struct inode *inode)
> * @inode: inode of interest
> *
> * Returns the wb @inode is currently associated with. The caller must be
> - * holding either @inode->i_lock, @inode->i_mapping->tree_lock, or the
> + * holding either @inode->i_lock, @inode->i_mapping->pages.xa_lock, or the
> * associated wb's list_lock.
> */
> static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
> @@ -337,7 +337,7 @@ static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
> #ifdef CONFIG_LOCKDEP
> WARN_ON_ONCE(debug_locks &&
> (!lockdep_is_held(&inode->i_lock) &&
> - !lockdep_is_held(&inode->i_mapping->tree_lock) &&
> + !lockdep_is_held(&inode->i_mapping->pages.xa_lock) &&
> !lockdep_is_held(&inode->i_wb->list_lock)));
> #endif
> return inode->i_wb;
> @@ -349,7 +349,7 @@ static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
> * @lockedp: temp bool output param, to be passed to the end function
> *
> * The caller wants to access the wb associated with @inode but isn't
> - * holding inode->i_lock, mapping->tree_lock or wb->list_lock. This
> + * holding inode->i_lock, mapping->pages.xa_lock or wb->list_lock. This
> * function determines the wb associated with @inode and ensures that the
> * association doesn't change until the transaction is finished with
> * unlocked_inode_to_wb_end().
> @@ -370,10 +370,10 @@ unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
> *lockedp = smp_load_acquire(&inode->i_state) & I_WB_SWITCH;
>
> if (unlikely(*lockedp))
> - spin_lock_irq(&inode->i_mapping->tree_lock);
> + xa_lock_irq(&inode->i_mapping->pages);
>
> /*
> - * Protected by either !I_WB_SWITCH + rcu_read_lock() or tree_lock.
> + * Protected by either !I_WB_SWITCH + rcu_read_lock() or xa_lock.
> * inode_to_wb() will bark. Deref directly.
> */
> return inode->i_wb;
> @@ -387,7 +387,7 @@ unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
> static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked)
> {
> if (unlikely(locked))
> - spin_unlock_irq(&inode->i_mapping->tree_lock);
> + xa_unlock_irq(&inode->i_mapping->pages);
>
> rcu_read_unlock();
> }
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 2a815560fda0..e227f68e0418 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -13,6 +13,7 @@
> #include <linux/list_lru.h>
> #include <linux/llist.h>
> #include <linux/radix-tree.h>
> +#include <linux/xarray.h>
> #include <linux/rbtree.h>
> #include <linux/init.h>
> #include <linux/pid.h>
> @@ -390,23 +391,21 @@ int pagecache_write_end(struct file *, struct address_space *mapping,
>
> struct address_space {
> struct inode *host; /* owner: inode, block_device */
> - struct radix_tree_root page_tree; /* radix tree of all pages */
> - spinlock_t tree_lock; /* and lock protecting it */
> + struct radix_tree_root pages; /* cached pages */
> + gfp_t gfp_mask; /* for allocating pages */
> atomic_t i_mmap_writable;/* count VM_SHARED mappings */
> struct rb_root_cached i_mmap; /* tree of private and shared mappings */
> struct rw_semaphore i_mmap_rwsem; /* protect tree, count, list */
> - /* Protected by tree_lock together with the radix tree */
> + /* Protected by pages.xa_lock */
> unsigned long nrpages; /* number of total pages */
> - /* number of shadow or DAX exceptional entries */
> - unsigned long nrexceptional;
> + unsigned long nrexceptional; /* shadow or DAX entries */
> pgoff_t writeback_index;/* writeback starts here */
> const struct address_space_operations *a_ops; /* methods */
> unsigned long flags; /* error bits */
> + errseq_t wb_err;
> spinlock_t private_lock; /* for use by the address_space */
> - gfp_t gfp_mask; /* implicit gfp mask for allocations */
> - struct list_head private_list; /* for use by the address_space */
> + struct list_head private_list; /* ditto */
> void *private_data; /* ditto */
> - errseq_t wb_err;
> } __attribute__((aligned(sizeof(long)))) __randomize_layout;
> /*
> * On most architectures that alignment is already the case; but
> @@ -1986,7 +1985,7 @@ static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
> *
> * I_WB_SWITCH Cgroup bdi_writeback switching in progress. Used to
> * synchronize competing switching instances and to tell
> - * wb stat updates to grab mapping->tree_lock. See
> + * wb stat updates to grab mapping->pages.xa_lock. See
> * inode_switch_wb_work_fn() for details.
> *
> * I_OVL_INUSE Used by overlayfs to get exclusive ownership on upper
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 47b0fb0a6e41..aad22344d685 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -738,7 +738,7 @@ int finish_mkwrite_fault(struct vm_fault *vmf);
> * refcount. The each user mapping also has a reference to the page.
> *
> * The pagecache pages are stored in a per-mapping radix tree, which is
> - * rooted at mapping->page_tree, and indexed by offset.
> + * rooted at mapping->pages, and indexed by offset.
> * Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
> * lists, we instead now tag pages as dirty/writeback in the radix tree.
> *
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 34ce3ebf97d5..80a6149152d4 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -144,7 +144,7 @@ void release_pages(struct page **pages, int nr);
> * 3. check the page is still in pagecache (if no, goto 1)
> *
> * Remove-side that cares about stability of _refcount (eg. reclaim) has the
> - * following (with tree_lock held for write):
> + * following (with pages.xa_lock held):
> * A. atomically check refcount is correct and set it to 0 (atomic_cmpxchg)
> * B. remove page from pagecache
> * C. free the page
> @@ -157,7 +157,7 @@ void release_pages(struct page **pages, int nr);
> *
> * It is possible that between 1 and 2, the page is removed then the exact same
> * page is inserted into the same position in pagecache. That's OK: the
> - * old find_get_page using tree_lock could equally have run before or after
> + * old find_get_page using a lock could equally have run before or after
> * such a re-insertion, depending on order that locks are granted.
> *
> * Lookups racing against pagecache insertion isn't a big problem: either 1
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 693f62212a59..7588b7f1f479 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -66,7 +66,7 @@
> * ->i_mmap_rwsem (truncate_pagecache)
> * ->private_lock (__free_pte->__set_page_dirty_buffers)
> * ->swap_lock (exclusive_swap_page, others)
> - * ->mapping->tree_lock
> + * ->mapping->pages.xa_lock
> *
> * ->i_mutex
> * ->i_mmap_rwsem (truncate->unmap_mapping_range)
> @@ -74,7 +74,7 @@
> * ->mmap_sem
> * ->i_mmap_rwsem
> * ->page_table_lock or pte_lock (various, mainly in memory.c)
> - * ->mapping->tree_lock (arch-dependent flush_dcache_mmap_lock)
> + * ->mapping->pages.xa_lock (arch-dependent flush_dcache_mmap_lock)
> *
> * ->mmap_sem
> * ->lock_page (access_process_vm)
> @@ -84,7 +84,7 @@
> *
> * bdi->wb.list_lock
> * sb_lock (fs/fs-writeback.c)
> - * ->mapping->tree_lock (__sync_single_inode)
> + * ->mapping->pages.xa_lock (__sync_single_inode)
> *
> * ->i_mmap_rwsem
> * ->anon_vma.lock (vma_adjust)
> @@ -95,11 +95,11 @@
> * ->page_table_lock or pte_lock
> * ->swap_lock (try_to_unmap_one)
> * ->private_lock (try_to_unmap_one)
> - * ->tree_lock (try_to_unmap_one)
> + * ->pages.xa_lock (try_to_unmap_one)
> * ->zone_lru_lock(zone) (follow_page->mark_page_accessed)
> * ->zone_lru_lock(zone) (check_pte_range->isolate_lru_page)
> * ->private_lock (page_remove_rmap->set_page_dirty)
> - * ->tree_lock (page_remove_rmap->set_page_dirty)
> + * ->pages.xa_lock (page_remove_rmap->set_page_dirty)
> * bdi.wb->list_lock (page_remove_rmap->set_page_dirty)
> * ->inode->i_lock (page_remove_rmap->set_page_dirty)
> * ->memcg->move_lock (page_remove_rmap->lock_page_memcg)
> @@ -118,14 +118,15 @@ static int page_cache_tree_insert(struct address_space *mapping,
> void **slot;
> int error;
>
> - error = __radix_tree_create(&mapping->page_tree, page->index, 0,
> + error = __radix_tree_create(&mapping->pages, page->index, 0,
> &node, &slot);
> if (error)
> return error;
> if (*slot) {
> void *p;
>
> - p = radix_tree_deref_slot_protected(slot, &mapping->tree_lock);
> + p = radix_tree_deref_slot_protected(slot,
> + &mapping->pages.xa_lock);
> if (!radix_tree_exceptional_entry(p))
> return -EEXIST;
>
> @@ -133,7 +134,7 @@ static int page_cache_tree_insert(struct address_space *mapping,
> if (shadowp)
> *shadowp = p;
> }
> - __radix_tree_replace(&mapping->page_tree, node, slot, page,
> + __radix_tree_replace(&mapping->pages, node, slot, page,
> workingset_lookup_update(mapping));
> mapping->nrpages++;
> return 0;
> @@ -155,13 +156,13 @@ static void page_cache_tree_delete(struct address_space *mapping,
> struct radix_tree_node *node;
> void **slot;
>
> - __radix_tree_lookup(&mapping->page_tree, page->index + i,
> + __radix_tree_lookup(&mapping->pages, page->index + i,
> &node, &slot);
>
> VM_BUG_ON_PAGE(!node && nr != 1, page);
>
> - radix_tree_clear_tags(&mapping->page_tree, node, slot);
> - __radix_tree_replace(&mapping->page_tree, node, slot, shadow,
> + radix_tree_clear_tags(&mapping->pages, node, slot);
> + __radix_tree_replace(&mapping->pages, node, slot, shadow,
> workingset_lookup_update(mapping));
> }
>
> @@ -253,7 +254,7 @@ static void unaccount_page_cache_page(struct address_space *mapping,
> /*
> * Delete a page from the page cache and free it. Caller has to make
> * sure the page is locked and that nobody else uses it - or that usage
> - * is safe. The caller must hold the mapping's tree_lock.
> + * is safe. The caller must hold the xa_lock.
> */
> void __delete_from_page_cache(struct page *page, void *shadow)
> {
> @@ -296,9 +297,9 @@ void delete_from_page_cache(struct page *page)
> unsigned long flags;
>
> BUG_ON(!PageLocked(page));
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> __delete_from_page_cache(page, NULL);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
>
> page_cache_free_page(mapping, page);
> }
> @@ -309,14 +310,14 @@ EXPORT_SYMBOL(delete_from_page_cache);
> * @mapping: the mapping to which pages belong
> * @pvec: pagevec with pages to delete
> *
> - * The function walks over mapping->page_tree and removes pages passed in @pvec
> - * from the radix tree. The function expects @pvec to be sorted by page index.
> - * It tolerates holes in @pvec (radix tree entries at those indices are not
> + * The function walks over mapping->pages and removes pages passed in @pvec
> + * from the mapping. The function expects @pvec to be sorted by page index.
> + * It tolerates holes in @pvec (mapping entries at those indices are not
> * modified). The function expects only THP head pages to be present in the
> - * @pvec and takes care to delete all corresponding tail pages from the radix
> - * tree as well.
> + * @pvec and takes care to delete all corresponding tail pages from the
> + * mapping as well.
> *
> - * The function expects mapping->tree_lock to be held.
> + * The function expects xa_lock to be held.
> */
> static void
> page_cache_tree_delete_batch(struct address_space *mapping,
> @@ -330,11 +331,11 @@ page_cache_tree_delete_batch(struct address_space *mapping,
> pgoff_t start;
>
> start = pvec->pages[0]->index;
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, start) {
> if (i >= pagevec_count(pvec) && !tail_pages)
> break;
> page = radix_tree_deref_slot_protected(slot,
> - &mapping->tree_lock);
> + &mapping->pages.xa_lock);
> if (radix_tree_exceptional_entry(page))
> continue;
> if (!tail_pages) {
> @@ -357,8 +358,8 @@ page_cache_tree_delete_batch(struct address_space *mapping,
> } else {
> tail_pages--;
> }
> - radix_tree_clear_tags(&mapping->page_tree, iter.node, slot);
> - __radix_tree_replace(&mapping->page_tree, iter.node, slot, NULL,
> + radix_tree_clear_tags(&mapping->pages, iter.node, slot);
> + __radix_tree_replace(&mapping->pages, iter.node, slot, NULL,
> workingset_lookup_update(mapping));
> total_pages++;
> }
> @@ -374,14 +375,14 @@ void delete_from_page_cache_batch(struct address_space *mapping,
> if (!pagevec_count(pvec))
> return;
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> for (i = 0; i < pagevec_count(pvec); i++) {
> trace_mm_filemap_delete_from_page_cache(pvec->pages[i]);
>
> unaccount_page_cache_page(mapping, pvec->pages[i]);
> }
> page_cache_tree_delete_batch(mapping, pvec);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
>
> for (i = 0; i < pagevec_count(pvec); i++)
> page_cache_free_page(mapping, pvec->pages[i]);
> @@ -798,7 +799,7 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
> new->mapping = mapping;
> new->index = offset;
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> __delete_from_page_cache(old, NULL);
> error = page_cache_tree_insert(mapping, new, NULL);
> BUG_ON(error);
> @@ -810,7 +811,7 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
> __inc_node_page_state(new, NR_FILE_PAGES);
> if (PageSwapBacked(new))
> __inc_node_page_state(new, NR_SHMEM);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> mem_cgroup_migrate(old, new);
> radix_tree_preload_end();
> if (freepage)
> @@ -852,7 +853,7 @@ static int __add_to_page_cache_locked(struct page *page,
> page->mapping = mapping;
> page->index = offset;
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> error = page_cache_tree_insert(mapping, page, shadowp);
> radix_tree_preload_end();
> if (unlikely(error))
> @@ -861,7 +862,7 @@ static int __add_to_page_cache_locked(struct page *page,
> /* hugetlb pages do not participate in page cache accounting. */
> if (!huge)
> __inc_node_page_state(page, NR_FILE_PAGES);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> if (!huge)
> mem_cgroup_commit_charge(page, memcg, false, false);
> trace_mm_filemap_add_to_page_cache(page);
> @@ -869,7 +870,7 @@ static int __add_to_page_cache_locked(struct page *page,
> err_insert:
> page->mapping = NULL;
> /* Leave page->index set: truncation relies upon it */
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> if (!huge)
> mem_cgroup_cancel_charge(page, memcg, false);
> put_page(page);
> @@ -1353,7 +1354,7 @@ pgoff_t page_cache_next_hole(struct address_space *mapping,
> for (i = 0; i < max_scan; i++) {
> struct page *page;
>
> - page = radix_tree_lookup(&mapping->page_tree, index);
> + page = radix_tree_lookup(&mapping->pages, index);
> if (!page || radix_tree_exceptional_entry(page))
> break;
> index++;
> @@ -1394,7 +1395,7 @@ pgoff_t page_cache_prev_hole(struct address_space *mapping,
> for (i = 0; i < max_scan; i++) {
> struct page *page;
>
> - page = radix_tree_lookup(&mapping->page_tree, index);
> + page = radix_tree_lookup(&mapping->pages, index);
> if (!page || radix_tree_exceptional_entry(page))
> break;
> index--;
> @@ -1427,7 +1428,7 @@ struct page *find_get_entry(struct address_space *mapping, pgoff_t offset)
> rcu_read_lock();
> repeat:
> page = NULL;
> - pagep = radix_tree_lookup_slot(&mapping->page_tree, offset);
> + pagep = radix_tree_lookup_slot(&mapping->pages, offset);
> if (pagep) {
> page = radix_tree_deref_slot(pagep);
> if (unlikely(!page))
> @@ -1633,7 +1634,7 @@ unsigned find_get_entries(struct address_space *mapping,
> return 0;
>
> rcu_read_lock();
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, start) {
> struct page *head, *page;
> repeat:
> page = radix_tree_deref_slot(slot);
> @@ -1710,7 +1711,7 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
> return 0;
>
> rcu_read_lock();
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, *start) {
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, *start) {
> struct page *head, *page;
>
> if (iter.index > end)
> @@ -1795,7 +1796,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
> return 0;
>
> rcu_read_lock();
> - radix_tree_for_each_contig(slot, &mapping->page_tree, &iter, index) {
> + radix_tree_for_each_contig(slot, &mapping->pages, &iter, index) {
> struct page *head, *page;
> repeat:
> page = radix_tree_deref_slot(slot);
> @@ -1875,8 +1876,7 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
> return 0;
>
> rcu_read_lock();
> - radix_tree_for_each_tagged(slot, &mapping->page_tree,
> - &iter, *index, tag) {
> + radix_tree_for_each_tagged(slot, &mapping->pages, &iter, *index, tag) {
> struct page *head, *page;
>
> if (iter.index > end)
> @@ -1969,8 +1969,7 @@ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
> return 0;
>
> rcu_read_lock();
> - radix_tree_for_each_tagged(slot, &mapping->page_tree,
> - &iter, start, tag) {
> + radix_tree_for_each_tagged(slot, &mapping->pages, &iter, start, tag) {
> struct page *head, *page;
> repeat:
> page = radix_tree_deref_slot(slot);
> @@ -2624,8 +2623,7 @@ void filemap_map_pages(struct vm_fault *vmf,
> struct page *head, *page;
>
> rcu_read_lock();
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter,
> - start_pgoff) {
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, start_pgoff) {
> if (iter.index > end_pgoff)
> break;
> repeat:
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 87ab9b8f56b5..4b60f55f1f8b 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -2450,7 +2450,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> } else {
> /* Additional pin to radix tree */
> page_ref_add(head, 2);
> - spin_unlock(&head->mapping->tree_lock);
> + xa_unlock(&head->mapping->pages);
> }
>
> spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
> @@ -2658,15 +2658,15 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
> if (mapping) {
> void **pslot;
>
> - spin_lock(&mapping->tree_lock);
> - pslot = radix_tree_lookup_slot(&mapping->page_tree,
> + xa_lock(&mapping->pages);
> + pslot = radix_tree_lookup_slot(&mapping->pages,
> page_index(head));
> /*
> * Check if the head page is present in radix tree.
> * We assume all tail are present too, if head is there.
> */
> if (radix_tree_deref_slot_protected(pslot,
> - &mapping->tree_lock) != head)
> + &mapping->pages.xa_lock) != head)
> goto fail;
> }
>
> @@ -2700,7 +2700,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
> }
> spin_unlock(&pgdata->split_queue_lock);
> fail: if (mapping)
> - spin_unlock(&mapping->tree_lock);
> + xa_unlock(&mapping->pages);
> spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
> unfreeze_page(head);
> ret = -EBUSY;
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index b7e2268dfc9a..5800093fe94a 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -1339,8 +1339,8 @@ static void collapse_shmem(struct mm_struct *mm,
> */
>
> index = start;
> - spin_lock_irq(&mapping->tree_lock);
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
> + xa_lock_irq(&mapping->pages);
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, start) {
> int n = min(iter.index, end) - index;
>
> /*
> @@ -1353,7 +1353,7 @@ static void collapse_shmem(struct mm_struct *mm,
> }
> nr_none += n;
> for (; index < min(iter.index, end); index++) {
> - radix_tree_insert(&mapping->page_tree, index,
> + radix_tree_insert(&mapping->pages, index,
> new_page + (index % HPAGE_PMD_NR));
> }
>
> @@ -1362,16 +1362,16 @@ static void collapse_shmem(struct mm_struct *mm,
> break;
>
> page = radix_tree_deref_slot_protected(slot,
> - &mapping->tree_lock);
> + &mapping->pages.xa_lock);
> if (radix_tree_exceptional_entry(page) || !PageUptodate(page)) {
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> /* swap in or instantiate fallocated page */
> if (shmem_getpage(mapping->host, index, &page,
> SGP_NOHUGE)) {
> result = SCAN_FAIL;
> goto tree_unlocked;
> }
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> } else if (trylock_page(page)) {
> get_page(page);
> } else {
> @@ -1380,7 +1380,7 @@ static void collapse_shmem(struct mm_struct *mm,
> }
>
> /*
> - * The page must be locked, so we can drop the tree_lock
> + * The page must be locked, so we can drop the xa_lock
> * without racing with truncate.
> */
> VM_BUG_ON_PAGE(!PageLocked(page), page);
> @@ -1391,7 +1391,7 @@ static void collapse_shmem(struct mm_struct *mm,
> result = SCAN_TRUNCATED;
> goto out_unlock;
> }
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
>
> if (isolate_lru_page(page)) {
> result = SCAN_DEL_PAGE_LRU;
> @@ -1401,11 +1401,11 @@ static void collapse_shmem(struct mm_struct *mm,
> if (page_mapped(page))
> unmap_mapping_pages(mapping, index, 1, false);
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
>
> - slot = radix_tree_lookup_slot(&mapping->page_tree, index);
> + slot = radix_tree_lookup_slot(&mapping->pages, index);
> VM_BUG_ON_PAGE(page != radix_tree_deref_slot_protected(slot,
> - &mapping->tree_lock), page);
> + &mapping->pages.xa_lock), page);
> VM_BUG_ON_PAGE(page_mapped(page), page);
>
> /*
> @@ -1426,14 +1426,14 @@ static void collapse_shmem(struct mm_struct *mm,
> list_add_tail(&page->lru, &pagelist);
>
> /* Finally, replace with the new page. */
> - radix_tree_replace_slot(&mapping->page_tree, slot,
> + radix_tree_replace_slot(&mapping->pages, slot,
> new_page + (index % HPAGE_PMD_NR));
>
> slot = radix_tree_iter_resume(slot, &iter);
> index++;
> continue;
> out_lru:
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> putback_lru_page(page);
> out_isolate_failed:
> unlock_page(page);
> @@ -1459,14 +1459,14 @@ static void collapse_shmem(struct mm_struct *mm,
> }
>
> for (; index < end; index++) {
> - radix_tree_insert(&mapping->page_tree, index,
> + radix_tree_insert(&mapping->pages, index,
> new_page + (index % HPAGE_PMD_NR));
> }
> nr_none += n;
> }
>
> tree_locked:
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> tree_unlocked:
>
> if (result == SCAN_SUCCEED) {
> @@ -1515,9 +1515,8 @@ static void collapse_shmem(struct mm_struct *mm,
> } else {
> /* Something went wrong: rollback changes to the radix-tree */
> shmem_uncharge(mapping->host, nr_none);
> - spin_lock_irq(&mapping->tree_lock);
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter,
> - start) {
> + xa_lock_irq(&mapping->pages);
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, start) {
> if (iter.index >= end)
> break;
> page = list_first_entry_or_null(&pagelist,
> @@ -1527,8 +1526,7 @@ static void collapse_shmem(struct mm_struct *mm,
> break;
> nr_none--;
> /* Put holes back where they were */
> - radix_tree_delete(&mapping->page_tree,
> - iter.index);
> + radix_tree_delete(&mapping->pages, iter.index);
> continue;
> }
>
> @@ -1537,16 +1535,15 @@ static void collapse_shmem(struct mm_struct *mm,
> /* Unfreeze the page. */
> list_del(&page->lru);
> page_ref_unfreeze(page, 2);
> - radix_tree_replace_slot(&mapping->page_tree,
> - slot, page);
> + radix_tree_replace_slot(&mapping->pages, slot, page);
> slot = radix_tree_iter_resume(slot, &iter);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> putback_lru_page(page);
> unlock_page(page);
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> }
> VM_BUG_ON(nr_none);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
>
> /* Unfreeze new_page, caller would take care about freeing it */
> page_ref_unfreeze(new_page, 1);
> @@ -1574,7 +1571,7 @@ static void khugepaged_scan_shmem(struct mm_struct *mm,
> swap = 0;
> memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
> rcu_read_lock();
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, start) {
> if (iter.index >= start + HPAGE_PMD_NR)
> break;
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 670e99b68aa6..d89cb08ac39b 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5967,9 +5967,9 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
>
> /*
> * Interrupts should be disabled here because the caller holds the
> - * mapping->tree_lock lock which is taken with interrupts-off. It is
> + * mapping->pages xa_lock which is taken with interrupts-off. It is
> * important here to have the interrupts disabled because it is the
> - * only synchronisation we have for udpating the per-CPU variables.
> + * only synchronisation we have for updating the per-CPU variables.
> */
> VM_BUG_ON(!irqs_disabled());
> mem_cgroup_charge_statistics(memcg, page, PageTransHuge(page),
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 1e5525a25691..184bc1d0e187 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -466,20 +466,21 @@ int migrate_page_move_mapping(struct address_space *mapping,
> oldzone = page_zone(page);
> newzone = page_zone(newpage);
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
>
> - pslot = radix_tree_lookup_slot(&mapping->page_tree,
> + pslot = radix_tree_lookup_slot(&mapping->pages,
> page_index(page));
>
> expected_count += 1 + page_has_private(page);
> if (page_count(page) != expected_count ||
> - radix_tree_deref_slot_protected(pslot, &mapping->tree_lock) != page) {
> - spin_unlock_irq(&mapping->tree_lock);
> + radix_tree_deref_slot_protected(pslot,
> + &mapping->pages.xa_lock) != page) {
> + xa_unlock_irq(&mapping->pages);
> return -EAGAIN;
> }
>
> if (!page_ref_freeze(page, expected_count)) {
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return -EAGAIN;
> }
>
> @@ -493,7 +494,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
> if (mode == MIGRATE_ASYNC && head &&
> !buffer_migrate_lock_buffers(head, mode)) {
> page_ref_unfreeze(page, expected_count);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return -EAGAIN;
> }
>
> @@ -521,7 +522,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
> SetPageDirty(newpage);
> }
>
> - radix_tree_replace_slot(&mapping->page_tree, pslot, newpage);
> + radix_tree_replace_slot(&mapping->pages, pslot, newpage);
>
> /*
> * Drop cache reference from old page by unfreezing
> @@ -530,7 +531,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
> */
> page_ref_unfreeze(page, expected_count - 1);
>
> - spin_unlock(&mapping->tree_lock);
> + xa_unlock(&mapping->pages);
> /* Leave irq disabled to prevent preemption while updating stats */
>
> /*
> @@ -573,20 +574,19 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
> int expected_count;
> void **pslot;
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
>
> - pslot = radix_tree_lookup_slot(&mapping->page_tree,
> - page_index(page));
> + pslot = radix_tree_lookup_slot(&mapping->pages, page_index(page));
>
> expected_count = 2 + page_has_private(page);
> if (page_count(page) != expected_count ||
> - radix_tree_deref_slot_protected(pslot, &mapping->tree_lock) != page) {
> - spin_unlock_irq(&mapping->tree_lock);
> + radix_tree_deref_slot_protected(pslot, &mapping->pages.xa_lock) != page) {
> + xa_unlock_irq(&mapping->pages);
> return -EAGAIN;
> }
>
> if (!page_ref_freeze(page, expected_count)) {
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> return -EAGAIN;
> }
>
> @@ -595,11 +595,11 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
>
> get_page(newpage);
>
> - radix_tree_replace_slot(&mapping->page_tree, pslot, newpage);
> + radix_tree_replace_slot(&mapping->pages, pslot, newpage);
>
> page_ref_unfreeze(page, expected_count - 1);
>
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
>
> return MIGRATEPAGE_SUCCESS;
> }
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 586f31261c83..588ce729d199 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2099,7 +2099,7 @@ void __init page_writeback_init(void)
> * so that it can tag pages faster than a dirtying process can create them).
> */
> /*
> - * We tag pages in batches of WRITEBACK_TAG_BATCH to reduce tree_lock latency.
> + * We tag pages in batches of WRITEBACK_TAG_BATCH to reduce xa_lock latency.
> */
> void tag_pages_for_writeback(struct address_space *mapping,
> pgoff_t start, pgoff_t end)
> @@ -2109,22 +2109,22 @@ void tag_pages_for_writeback(struct address_space *mapping,
> struct radix_tree_iter iter;
> void **slot;
>
> - spin_lock_irq(&mapping->tree_lock);
> - radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, start,
> + xa_lock_irq(&mapping->pages);
> + radix_tree_for_each_tagged(slot, &mapping->pages, &iter, start,
> PAGECACHE_TAG_DIRTY) {
> if (iter.index > end)
> break;
> - radix_tree_iter_tag_set(&mapping->page_tree, &iter,
> + radix_tree_iter_tag_set(&mapping->pages, &iter,
> PAGECACHE_TAG_TOWRITE);
> tagged++;
> if ((tagged % WRITEBACK_TAG_BATCH) != 0)
> continue;
> slot = radix_tree_iter_resume(slot, &iter);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> cond_resched();
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> }
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> }
> EXPORT_SYMBOL(tag_pages_for_writeback);
>
> @@ -2467,13 +2467,13 @@ int __set_page_dirty_nobuffers(struct page *page)
> return 1;
> }
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> BUG_ON(page_mapping(page) != mapping);
> WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
> account_page_dirtied(page, mapping);
> - radix_tree_tag_set(&mapping->page_tree, page_index(page),
> + radix_tree_tag_set(&mapping->pages, page_index(page),
> PAGECACHE_TAG_DIRTY);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> unlock_page_memcg(page);
>
> if (mapping->host) {
> @@ -2718,11 +2718,10 @@ int test_clear_page_writeback(struct page *page)
> struct backing_dev_info *bdi = inode_to_bdi(inode);
> unsigned long flags;
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> ret = TestClearPageWriteback(page);
> if (ret) {
> - radix_tree_tag_clear(&mapping->page_tree,
> - page_index(page),
> + radix_tree_tag_clear(&mapping->pages, page_index(page),
> PAGECACHE_TAG_WRITEBACK);
> if (bdi_cap_account_writeback(bdi)) {
> struct bdi_writeback *wb = inode_to_wb(inode);
> @@ -2736,7 +2735,7 @@ int test_clear_page_writeback(struct page *page)
> PAGECACHE_TAG_WRITEBACK))
> sb_clear_inode_writeback(mapping->host);
>
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> } else {
> ret = TestClearPageWriteback(page);
> }
> @@ -2766,7 +2765,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
> struct backing_dev_info *bdi = inode_to_bdi(inode);
> unsigned long flags;
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> ret = TestSetPageWriteback(page);
> if (!ret) {
> bool on_wblist;
> @@ -2774,8 +2773,7 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
> on_wblist = mapping_tagged(mapping,
> PAGECACHE_TAG_WRITEBACK);
>
> - radix_tree_tag_set(&mapping->page_tree,
> - page_index(page),
> + radix_tree_tag_set(&mapping->pages, page_index(page),
> PAGECACHE_TAG_WRITEBACK);
> if (bdi_cap_account_writeback(bdi))
> inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK);
> @@ -2789,14 +2787,12 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
> sb_mark_inode_writeback(mapping->host);
> }
> if (!PageDirty(page))
> - radix_tree_tag_clear(&mapping->page_tree,
> - page_index(page),
> + radix_tree_tag_clear(&mapping->pages, page_index(page),
> PAGECACHE_TAG_DIRTY);
> if (!keep_write)
> - radix_tree_tag_clear(&mapping->page_tree,
> - page_index(page),
> + radix_tree_tag_clear(&mapping->pages, page_index(page),
> PAGECACHE_TAG_TOWRITE);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> } else {
> ret = TestSetPageWriteback(page);
> }
> @@ -2816,7 +2812,7 @@ EXPORT_SYMBOL(__test_set_page_writeback);
> */
> int mapping_tagged(struct address_space *mapping, int tag)
> {
> - return radix_tree_tagged(&mapping->page_tree, tag);
> + return radix_tree_tagged(&mapping->pages, tag);
> }
> EXPORT_SYMBOL(mapping_tagged);
>
> diff --git a/mm/readahead.c b/mm/readahead.c
> index c4ca70239233..514188fd2489 100644
> --- a/mm/readahead.c
> +++ b/mm/readahead.c
> @@ -175,7 +175,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
> break;
>
> rcu_read_lock();
> - page = radix_tree_lookup(&mapping->page_tree, page_offset);
> + page = radix_tree_lookup(&mapping->pages, page_offset);
> rcu_read_unlock();
> if (page && !radix_tree_exceptional_entry(page))
> continue;
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 47db27f8049e..87c1ca0cf1a3 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -32,11 +32,11 @@
> * mmlist_lock (in mmput, drain_mmlist and others)
> * mapping->private_lock (in __set_page_dirty_buffers)
> * mem_cgroup_{begin,end}_page_stat (memcg->move_lock)
> - * mapping->tree_lock (widely used)
> + * mapping->pages.xa_lock (widely used)
> * inode->i_lock (in set_page_dirty's __mark_inode_dirty)
> * bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
> * sb_lock (within inode_lock in fs/fs-writeback.c)
> - * mapping->tree_lock (widely used, in set_page_dirty,
> + * mapping->pages.xa_lock (widely used, in set_page_dirty,
> * in arch-dependent flush_dcache_mmap_lock,
> * within bdi.wb->list_lock in __sync_single_inode)
> *
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 1907688b75ee..b2fdc258853d 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -332,12 +332,12 @@ static int shmem_radix_tree_replace(struct address_space *mapping,
>
> VM_BUG_ON(!expected);
> VM_BUG_ON(!replacement);
> - item = __radix_tree_lookup(&mapping->page_tree, index, &node, &pslot);
> + item = __radix_tree_lookup(&mapping->pages, index, &node, &pslot);
> if (!item)
> return -ENOENT;
> if (item != expected)
> return -ENOENT;
> - __radix_tree_replace(&mapping->page_tree, node, pslot,
> + __radix_tree_replace(&mapping->pages, node, pslot,
> replacement, NULL);
> return 0;
> }
> @@ -355,7 +355,7 @@ static bool shmem_confirm_swap(struct address_space *mapping,
> void *item;
>
> rcu_read_lock();
> - item = radix_tree_lookup(&mapping->page_tree, index);
> + item = radix_tree_lookup(&mapping->pages, index);
> rcu_read_unlock();
> return item == swp_to_radix_entry(swap);
> }
> @@ -581,14 +581,14 @@ static int shmem_add_to_page_cache(struct page *page,
> page->mapping = mapping;
> page->index = index;
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> if (PageTransHuge(page)) {
> void __rcu **results;
> pgoff_t idx;
> int i;
>
> error = 0;
> - if (radix_tree_gang_lookup_slot(&mapping->page_tree,
> + if (radix_tree_gang_lookup_slot(&mapping->pages,
> &results, &idx, index, 1) &&
> idx < index + HPAGE_PMD_NR) {
> error = -EEXIST;
> @@ -596,14 +596,14 @@ static int shmem_add_to_page_cache(struct page *page,
>
> if (!error) {
> for (i = 0; i < HPAGE_PMD_NR; i++) {
> - error = radix_tree_insert(&mapping->page_tree,
> + error = radix_tree_insert(&mapping->pages,
> index + i, page + i);
> VM_BUG_ON(error);
> }
> count_vm_event(THP_FILE_ALLOC);
> }
> } else if (!expected) {
> - error = radix_tree_insert(&mapping->page_tree, index, page);
> + error = radix_tree_insert(&mapping->pages, index, page);
> } else {
> error = shmem_radix_tree_replace(mapping, index, expected,
> page);
> @@ -615,10 +615,10 @@ static int shmem_add_to_page_cache(struct page *page,
> __inc_node_page_state(page, NR_SHMEM_THPS);
> __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr);
> __mod_node_page_state(page_pgdat(page), NR_SHMEM, nr);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> } else {
> page->mapping = NULL;
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> page_ref_sub(page, nr);
> }
> return error;
> @@ -634,13 +634,13 @@ static void shmem_delete_from_page_cache(struct page *page, void *radswap)
>
> VM_BUG_ON_PAGE(PageCompound(page), page);
>
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> error = shmem_radix_tree_replace(mapping, page->index, page, radswap);
> page->mapping = NULL;
> mapping->nrpages--;
> __dec_node_page_state(page, NR_FILE_PAGES);
> __dec_node_page_state(page, NR_SHMEM);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> put_page(page);
> BUG_ON(error);
> }
> @@ -653,9 +653,9 @@ static int shmem_free_swap(struct address_space *mapping,
> {
> void *old;
>
> - spin_lock_irq(&mapping->tree_lock);
> - old = radix_tree_delete_item(&mapping->page_tree, index, radswap);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> + old = radix_tree_delete_item(&mapping->pages, index, radswap);
> + xa_unlock_irq(&mapping->pages);
> if (old != radswap)
> return -ENOENT;
> free_swap_and_cache(radix_to_swp_entry(radswap));
> @@ -666,7 +666,7 @@ static int shmem_free_swap(struct address_space *mapping,
> * Determine (in bytes) how many of the shmem object's pages mapped by the
> * given offsets are swapped out.
> *
> - * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU,
> + * This is safe to call without i_mutex or mapping->pages.xa_lock thanks to RCU,
> * as long as the inode doesn't go away and racy results are not a problem.
> */
> unsigned long shmem_partial_swap_usage(struct address_space *mapping,
> @@ -679,7 +679,7 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping,
>
> rcu_read_lock();
>
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, start) {
> if (iter.index >= end)
> break;
>
> @@ -708,7 +708,7 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping,
> * Determine (in bytes) how many of the shmem object's pages mapped by the
> * given vma is swapped out.
> *
> - * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU,
> + * This is safe to call without i_mutex or mapping->pages.xa_lock thanks to RCU,
> * as long as the inode doesn't go away and racy results are not a problem.
> */
> unsigned long shmem_swap_usage(struct vm_area_struct *vma)
> @@ -1123,7 +1123,7 @@ static int shmem_unuse_inode(struct shmem_inode_info *info,
> int error = 0;
>
> radswap = swp_to_radix_entry(swap);
> - index = find_swap_entry(&mapping->page_tree, radswap);
> + index = find_swap_entry(&mapping->pages, radswap);
> if (index == -1)
> return -EAGAIN; /* tell shmem_unuse we found nothing */
>
> @@ -1436,7 +1436,7 @@ static struct page *shmem_alloc_hugepage(gfp_t gfp,
>
> hindex = round_down(index, HPAGE_PMD_NR);
> rcu_read_lock();
> - if (radix_tree_gang_lookup_slot(&mapping->page_tree, &results, &idx,
> + if (radix_tree_gang_lookup_slot(&mapping->pages, &results, &idx,
> hindex, 1) && idx < hindex + HPAGE_PMD_NR) {
> rcu_read_unlock();
> return NULL;
> @@ -1549,14 +1549,14 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
> * Our caller will very soon move newpage out of swapcache, but it's
> * a nice clean interface for us to replace oldpage by newpage there.
> */
> - spin_lock_irq(&swap_mapping->tree_lock);
> + xa_lock_irq(&swap_mapping->pages);
> error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage,
> newpage);
> if (!error) {
> __inc_node_page_state(newpage, NR_FILE_PAGES);
> __dec_node_page_state(oldpage, NR_FILE_PAGES);
> }
> - spin_unlock_irq(&swap_mapping->tree_lock);
> + xa_unlock_irq(&swap_mapping->pages);
>
> if (unlikely(error)) {
> /*
> @@ -2622,7 +2622,7 @@ static void shmem_tag_pins(struct address_space *mapping)
> start = 0;
> rcu_read_lock();
>
> - radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
> + radix_tree_for_each_slot(slot, &mapping->pages, &iter, start) {
> page = radix_tree_deref_slot(slot);
> if (!page || radix_tree_exception(page)) {
> if (radix_tree_deref_retry(page)) {
> @@ -2630,10 +2630,10 @@ static void shmem_tag_pins(struct address_space *mapping)
> continue;
> }
> } else if (page_count(page) - page_mapcount(page) > 1) {
> - spin_lock_irq(&mapping->tree_lock);
> - radix_tree_tag_set(&mapping->page_tree, iter.index,
> + xa_lock_irq(&mapping->pages);
> + radix_tree_tag_set(&mapping->pages, iter.index,
> SHMEM_TAG_PINNED);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> }
>
> if (need_resched()) {
> @@ -2665,7 +2665,7 @@ static int shmem_wait_for_pins(struct address_space *mapping)
>
> error = 0;
> for (scan = 0; scan <= LAST_SCAN; scan++) {
> - if (!radix_tree_tagged(&mapping->page_tree, SHMEM_TAG_PINNED))
> + if (!radix_tree_tagged(&mapping->pages, SHMEM_TAG_PINNED))
> break;
>
> if (!scan)
> @@ -2675,7 +2675,7 @@ static int shmem_wait_for_pins(struct address_space *mapping)
>
> start = 0;
> rcu_read_lock();
> - radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter,
> + radix_tree_for_each_tagged(slot, &mapping->pages, &iter,
> start, SHMEM_TAG_PINNED) {
>
> page = radix_tree_deref_slot(slot);
> @@ -2701,10 +2701,10 @@ static int shmem_wait_for_pins(struct address_space *mapping)
> error = -EBUSY;
> }
>
> - spin_lock_irq(&mapping->tree_lock);
> - radix_tree_tag_clear(&mapping->page_tree,
> + xa_lock_irq(&mapping->pages);
> + radix_tree_tag_clear(&mapping->pages,
> iter.index, SHMEM_TAG_PINNED);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> continue_resched:
> if (need_resched()) {
> slot = radix_tree_iter_resume(slot, &iter);
> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index 39ae7cfad90f..3f95e8fc4cb2 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -124,10 +124,10 @@ int __add_to_swap_cache(struct page *page, swp_entry_t entry)
> SetPageSwapCache(page);
>
> address_space = swap_address_space(entry);
> - spin_lock_irq(&address_space->tree_lock);
> + xa_lock_irq(&address_space->pages);
> for (i = 0; i < nr; i++) {
> set_page_private(page + i, entry.val + i);
> - error = radix_tree_insert(&address_space->page_tree,
> + error = radix_tree_insert(&address_space->pages,
> idx + i, page + i);
> if (unlikely(error))
> break;
> @@ -145,13 +145,13 @@ int __add_to_swap_cache(struct page *page, swp_entry_t entry)
> VM_BUG_ON(error == -EEXIST);
> set_page_private(page + i, 0UL);
> while (i--) {
> - radix_tree_delete(&address_space->page_tree, idx + i);
> + radix_tree_delete(&address_space->pages, idx + i);
> set_page_private(page + i, 0UL);
> }
> ClearPageSwapCache(page);
> page_ref_sub(page, nr);
> }
> - spin_unlock_irq(&address_space->tree_lock);
> + xa_unlock_irq(&address_space->pages);
>
> return error;
> }
> @@ -188,7 +188,7 @@ void __delete_from_swap_cache(struct page *page)
> address_space = swap_address_space(entry);
> idx = swp_offset(entry);
> for (i = 0; i < nr; i++) {
> - radix_tree_delete(&address_space->page_tree, idx + i);
> + radix_tree_delete(&address_space->pages, idx + i);
> set_page_private(page + i, 0);
> }
> ClearPageSwapCache(page);
> @@ -272,9 +272,9 @@ void delete_from_swap_cache(struct page *page)
> entry.val = page_private(page);
>
> address_space = swap_address_space(entry);
> - spin_lock_irq(&address_space->tree_lock);
> + xa_lock_irq(&address_space->pages);
> __delete_from_swap_cache(page);
> - spin_unlock_irq(&address_space->tree_lock);
> + xa_unlock_irq(&address_space->pages);
>
> put_swap_page(page, entry);
> page_ref_sub(page, hpage_nr_pages(page));
> @@ -612,12 +612,11 @@ int init_swap_address_space(unsigned int type, unsigned long nr_pages)
> return -ENOMEM;
> for (i = 0; i < nr; i++) {
> space = spaces + i;
> - INIT_RADIX_TREE(&space->page_tree, GFP_ATOMIC|__GFP_NOWARN);
> + INIT_RADIX_TREE(&space->pages, GFP_ATOMIC|__GFP_NOWARN);
> atomic_set(&space->i_mmap_writable, 0);
> space->a_ops = &swap_aops;
> /* swap cache doesn't use writeback related tags */
> mapping_set_no_writeback_tags(space);
> - spin_lock_init(&space->tree_lock);
> }
> nr_swapper_spaces[type] = nr;
> rcu_assign_pointer(swapper_spaces[type], spaces);
> diff --git a/mm/truncate.c b/mm/truncate.c
> index c34e2fd4f583..295a33a06fac 100644
> --- a/mm/truncate.c
> +++ b/mm/truncate.c
> @@ -36,11 +36,11 @@ static inline void __clear_shadow_entry(struct address_space *mapping,
> struct radix_tree_node *node;
> void **slot;
>
> - if (!__radix_tree_lookup(&mapping->page_tree, index, &node, &slot))
> + if (!__radix_tree_lookup(&mapping->pages, index, &node, &slot))
> return;
> if (*slot != entry)
> return;
> - __radix_tree_replace(&mapping->page_tree, node, slot, NULL,
> + __radix_tree_replace(&mapping->pages, node, slot, NULL,
> workingset_update_node);
> mapping->nrexceptional--;
> }
> @@ -48,9 +48,9 @@ static inline void __clear_shadow_entry(struct address_space *mapping,
> static void clear_shadow_entry(struct address_space *mapping, pgoff_t index,
> void *entry)
> {
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> __clear_shadow_entry(mapping, index, entry);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> }
>
> /*
> @@ -79,7 +79,7 @@ static void truncate_exceptional_pvec_entries(struct address_space *mapping,
> dax = dax_mapping(mapping);
> lock = !dax && indices[j] < end;
> if (lock)
> - spin_lock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
>
> for (i = j; i < pagevec_count(pvec); i++) {
> struct page *page = pvec->pages[i];
> @@ -102,7 +102,7 @@ static void truncate_exceptional_pvec_entries(struct address_space *mapping,
> }
>
> if (lock)
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_unlock_irq(&mapping->pages);
> pvec->nr = j;
> }
>
> @@ -518,8 +518,8 @@ void truncate_inode_pages_final(struct address_space *mapping)
> * modification that does not see AS_EXITING is
> * completed before starting the final truncate.
> */
> - spin_lock_irq(&mapping->tree_lock);
> - spin_unlock_irq(&mapping->tree_lock);
> + xa_lock_irq(&mapping->pages);
> + xa_unlock_irq(&mapping->pages);
>
> truncate_inode_pages(mapping, 0);
> }
> @@ -627,13 +627,13 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
> if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
> return 0;
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> if (PageDirty(page))
> goto failed;
>
> BUG_ON(page_has_private(page));
> __delete_from_page_cache(page, NULL);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
>
> if (mapping->a_ops->freepage)
> mapping->a_ops->freepage(page);
> @@ -641,7 +641,7 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
> put_page(page); /* pagecache ref */
> return 1;
> failed:
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> return 0;
> }
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 444749669187..93f4b4634431 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -656,7 +656,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
> BUG_ON(!PageLocked(page));
> BUG_ON(mapping != page_mapping(page));
>
> - spin_lock_irqsave(&mapping->tree_lock, flags);
> + xa_lock_irqsave(&mapping->pages, flags);
> /*
> * The non racy check for a busy page.
> *
> @@ -680,7 +680,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
> * load is not satisfied before that of page->_refcount.
> *
> * Note that if SetPageDirty is always performed via set_page_dirty,
> - * and thus under tree_lock, then this ordering is not required.
> + * and thus under xa_lock, then this ordering is not required.
> */
> if (unlikely(PageTransHuge(page)) && PageSwapCache(page))
> refcount = 1 + HPAGE_PMD_NR;
> @@ -698,7 +698,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
> swp_entry_t swap = { .val = page_private(page) };
> mem_cgroup_swapout(page, swap);
> __delete_from_swap_cache(page);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> put_swap_page(page, swap);
> } else {
> void (*freepage)(struct page *);
> @@ -719,13 +719,13 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
> * only page cache pages found in these are zero pages
> * covering holes, and because we don't want to mix DAX
> * exceptional entries and shadow exceptional entries in the
> - * same page_tree.
> + * same address_space.
> */
> if (reclaimed && page_is_file_cache(page) &&
> !mapping_exiting(mapping) && !dax_mapping(mapping))
> shadow = workingset_eviction(mapping, page);
> __delete_from_page_cache(page, shadow);
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
>
> if (freepage != NULL)
> freepage(page);
> @@ -734,7 +734,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
> return 1;
>
> cannot_free:
> - spin_unlock_irqrestore(&mapping->tree_lock, flags);
> + xa_unlock_irqrestore(&mapping->pages, flags);
> return 0;
> }
>
> diff --git a/mm/workingset.c b/mm/workingset.c
> index b7d616a3bbbe..3cb3586181e6 100644
> --- a/mm/workingset.c
> +++ b/mm/workingset.c
> @@ -202,7 +202,7 @@ static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat,
> * @mapping: address space the page was backing
> * @page: the page being evicted
> *
> - * Returns a shadow entry to be stored in @mapping->page_tree in place
> + * Returns a shadow entry to be stored in @mapping->pages in place
> * of the evicted @page so that a later refault can be detected.
> */
> void *workingset_eviction(struct address_space *mapping, struct page *page)
> @@ -348,7 +348,7 @@ void workingset_update_node(struct radix_tree_node *node)
> *
> * Avoid acquiring the list_lru lock when the nodes are
> * already where they should be. The list_empty() test is safe
> - * as node->private_list is protected by &mapping->tree_lock.
> + * as node->private_list is protected by mapping->pages.xa_lock.
> */
> if (node->count && node->count == node->exceptional) {
> if (list_empty(&node->private_list))
> @@ -366,7 +366,7 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
> unsigned long nodes;
> unsigned long cache;
>
> - /* list_lru lock nests inside IRQ-safe mapping->tree_lock */
> + /* list_lru lock nests inside IRQ-safe mapping->pages.xa_lock */
> local_irq_disable();
> nodes = list_lru_shrink_count(&shadow_nodes, sc);
> local_irq_enable();
> @@ -419,21 +419,21 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
>
> /*
> * Page cache insertions and deletions synchroneously maintain
> - * the shadow node LRU under the mapping->tree_lock and the
> + * the shadow node LRU under the mapping->pages.xa_lock and the
> * lru_lock. Because the page cache tree is emptied before
> * the inode can be destroyed, holding the lru_lock pins any
> * address_space that has radix tree nodes on the LRU.
> *
> - * We can then safely transition to the mapping->tree_lock to
> + * We can then safely transition to the mapping->pages.xa_lock to
> * pin only the address_space of the particular node we want
> * to reclaim, take the node off-LRU, and drop the lru_lock.
> */
>
> node = container_of(item, struct radix_tree_node, private_list);
> - mapping = container_of(node->root, struct address_space, page_tree);
> + mapping = container_of(node->root, struct address_space, pages);
>
> /* Coming from the list, invert the lock order */
> - if (!spin_trylock(&mapping->tree_lock)) {
> + if (!xa_trylock(&mapping->pages)) {
> spin_unlock(lru_lock);
> ret = LRU_RETRY;
> goto out;
> @@ -468,11 +468,11 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
> if (WARN_ON_ONCE(node->exceptional))
> goto out_invalid;
> inc_lruvec_page_state(virt_to_page(node), WORKINGSET_NODERECLAIM);
> - __radix_tree_delete_node(&mapping->page_tree, node,
> + __radix_tree_delete_node(&mapping->pages, node,
> workingset_lookup_update(mapping));
>
> out_invalid:
> - spin_unlock(&mapping->tree_lock);
> + xa_unlock(&mapping->pages);
> ret = LRU_REMOVED_RETRY;
> out:
> local_irq_enable();
> @@ -487,7 +487,7 @@ static unsigned long scan_shadow_nodes(struct shrinker *shrinker,
> {
> unsigned long ret;
>
> - /* list_lru lock nests inside IRQ-safe mapping->tree_lock */
> + /* list_lru lock nests inside IRQ-safe mapping->pages.xa_lock */
> local_irq_disable();
> ret = list_lru_shrink_walk(&shadow_nodes, sc, shadow_lru_isolate, NULL);
> local_irq_enable();
> @@ -503,7 +503,7 @@ static struct shrinker workingset_shadow_shrinker = {
>
> /*
> * Our list_lru->lock is IRQ-safe as it nests inside the IRQ-safe
> - * mapping->tree_lock.
> + * mapping->pages.xa_lock.
> */
> static struct lock_class_key shadow_nodes_key;
>
Straightforward change and the doc comments are a nice cleanup. Big
patch though and I didn't go over it in detail, so:
Acked-by: Jeff Layton <jlayton@...hat.com>
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