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Message-Id: <20180611140639.17215-51-willy@infradead.org>
Date: Mon, 11 Jun 2018 07:06:17 -0700
From: Matthew Wilcox <willy@...radead.org>
To: linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Matthew Wilcox <mawilcox@...rosoft.com>, Jan Kara <jack@...e.cz>,
Jeff Layton <jlayton@...hat.com>,
Lukas Czerner <lczerner@...hat.com>,
Ross Zwisler <ross.zwisler@...ux.intel.com>,
Christoph Hellwig <hch@....de>,
Goldwyn Rodrigues <rgoldwyn@...e.com>,
Nicholas Piggin <npiggin@...il.com>,
Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>,
linux-nilfs@...r.kernel.org, Jaegeuk Kim <jaegeuk@...nel.org>,
Chao Yu <yuchao0@...wei.com>,
linux-f2fs-devel@...ts.sourceforge.net
Subject: [PATCH v13 50/72] shmem: Convert shmem_alloc_hugepage to XArray
From: Matthew Wilcox <mawilcox@...rosoft.com>
xa_find() is a slightly easier API to use than
radix_tree_gang_lookup_slot() because it contains its own RCU locking.
This commit removes the last user of radix_tree_gang_lookup_slot()
so remove the function too.
Signed-off-by: Matthew Wilcox <mawilcox@...rosoft.com>
---
include/linux/radix-tree.h | 6 +-----
lib/radix-tree.c | 44 +-------------------------------------
mm/shmem.c | 14 ++++--------
3 files changed, 6 insertions(+), 58 deletions(-)
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index eefa0b099dd5..081e68b4376b 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -147,12 +147,11 @@ static inline unsigned int iter_shift(const struct radix_tree_iter *iter)
* radix_tree_lookup_slot
* radix_tree_tag_get
* radix_tree_gang_lookup
- * radix_tree_gang_lookup_slot
* radix_tree_gang_lookup_tag
* radix_tree_gang_lookup_tag_slot
* radix_tree_tagged
*
- * The first 8 functions are able to be called locklessly, using RCU. The
+ * The first 7 functions are able to be called locklessly, using RCU. The
* caller must ensure calls to these functions are made within rcu_read_lock()
* regions. Other readers (lock-free or otherwise) and modifications may be
* running concurrently.
@@ -263,9 +262,6 @@ void radix_tree_clear_tags(struct radix_tree_root *, struct radix_tree_node *,
unsigned int radix_tree_gang_lookup(const struct radix_tree_root *,
void **results, unsigned long first_index,
unsigned int max_items);
-unsigned int radix_tree_gang_lookup_slot(const struct radix_tree_root *,
- void __rcu ***results, unsigned long *indices,
- unsigned long first_index, unsigned int max_items);
int radix_tree_preload(gfp_t gfp_mask);
int radix_tree_maybe_preload(gfp_t gfp_mask);
int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order);
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 5c8a262f506c..d0f44ea96945 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -1138,7 +1138,7 @@ void __radix_tree_replace(struct radix_tree_root *root,
* @slot: pointer to slot
* @item: new item to store in the slot.
*
- * For use with radix_tree_lookup_slot(), radix_tree_gang_lookup_slot(),
+ * For use with radix_tree_lookup_slot() and
* radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked
* across slot lookup and replacement.
*
@@ -1772,48 +1772,6 @@ radix_tree_gang_lookup(const struct radix_tree_root *root, void **results,
}
EXPORT_SYMBOL(radix_tree_gang_lookup);
-/**
- * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree
- * @root: radix tree root
- * @results: where the results of the lookup are placed
- * @indices: where their indices should be placed (but usually NULL)
- * @first_index: start the lookup from this key
- * @max_items: place up to this many items at *results
- *
- * Performs an index-ascending scan of the tree for present items. Places
- * their slots at *@...ults and returns the number of items which were
- * placed at *@...ults.
- *
- * The implementation is naive.
- *
- * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must
- * be dereferenced with radix_tree_deref_slot, and if using only RCU
- * protection, radix_tree_deref_slot may fail requiring a retry.
- */
-unsigned int
-radix_tree_gang_lookup_slot(const struct radix_tree_root *root,
- void __rcu ***results, unsigned long *indices,
- unsigned long first_index, unsigned int max_items)
-{
- struct radix_tree_iter iter;
- void __rcu **slot;
- unsigned int ret = 0;
-
- if (unlikely(!max_items))
- return 0;
-
- radix_tree_for_each_slot(slot, root, &iter, first_index) {
- results[ret] = slot;
- if (indices)
- indices[ret] = iter.index;
- if (++ret == max_items)
- break;
- }
-
- return ret;
-}
-EXPORT_SYMBOL(radix_tree_gang_lookup_slot);
-
/**
* radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
* based on a tag
diff --git a/mm/shmem.c b/mm/shmem.c
index 8e702b6d84a5..09452ca79220 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1434,23 +1434,17 @@ static struct page *shmem_alloc_hugepage(gfp_t gfp,
struct shmem_inode_info *info, pgoff_t index)
{
struct vm_area_struct pvma;
- struct inode *inode = &info->vfs_inode;
- struct address_space *mapping = inode->i_mapping;
- pgoff_t idx, hindex;
- void __rcu **results;
+ struct address_space *mapping = info->vfs_inode.i_mapping;
+ pgoff_t hindex;
struct page *page;
if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
return NULL;
hindex = round_down(index, HPAGE_PMD_NR);
- rcu_read_lock();
- if (radix_tree_gang_lookup_slot(&mapping->i_pages, &results, &idx,
- hindex, 1) && idx < hindex + HPAGE_PMD_NR) {
- rcu_read_unlock();
+ if (xa_find(&mapping->i_pages, &hindex, hindex + HPAGE_PMD_NR - 1,
+ XA_PRESENT))
return NULL;
- }
- rcu_read_unlock();
shmem_pseudo_vma_init(&pvma, info, hindex);
page = alloc_pages_vma(gfp | __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN,
--
2.17.1
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