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Message-ID: <56F0D899.4040609@electrozaur.com>
Date: Tue, 22 Mar 2016 07:31:05 +0200
From: Boaz Harrosh <ooo@...ctrozaur.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
Linus Torvalds <torvalds@...ux-foundation.org>
CC: Christoph Lameter <cl@...ux.com>,
Matthew Wilcox <willy@...ux.intel.com>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
linux-fsdevel@...r.kernel.org,
Benny Halevy <bhalevy@...marydata.com>
Subject: Re: [PATCH 31/71] exofs: get rid of PAGE_CACHE_* and page_cache_{get,release}
macros
On 03/20/2016 08:40 PM, Kirill A. Shutemov wrote:
> PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago
> with promise that one day it will be possible to implement page cache with
> bigger chunks than PAGE_SIZE.
>
> This promise never materialized. And unlikely will.
>
> We have many places where PAGE_CACHE_SIZE assumed to be equal to
> PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_*
> or PAGE_* constant should be used in a particular case, especially on the
> border between fs and mm.
>
> Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
> breakage to be doable.
>
> Let's stop pretending that pages in page cache are special. They are not.
>
> The changes are pretty straight-forward:
>
> - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
>
> - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
>
> - page_cache_get() -> get_page();
>
> - page_cache_release() -> put_page();
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> Cc: Boaz Harrosh <ooo@...ctrozaur.com>
ACK-by: Boaz Harrosh <ooo@...ctrozaur.com>
Could you please push this through some other maintainer perhaps
the vfs tree?
Thank you Kirill
Boaz
> Cc: Benny Halevy <bhalevy@...marydata.com>
> ---
> fs/exofs/dir.c | 30 +++++++++++++++---------------
> fs/exofs/inode.c | 34 +++++++++++++++++-----------------
> fs/exofs/namei.c | 4 ++--
> 3 files changed, 34 insertions(+), 34 deletions(-)
>
> diff --git a/fs/exofs/dir.c b/fs/exofs/dir.c
> index e5bb2abf77f9..547b93cbea63 100644
> --- a/fs/exofs/dir.c
> +++ b/fs/exofs/dir.c
> @@ -41,16 +41,16 @@ static inline unsigned exofs_chunk_size(struct inode *inode)
> static inline void exofs_put_page(struct page *page)
> {
> kunmap(page);
> - page_cache_release(page);
> + put_page(page);
> }
>
> static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
> {
> loff_t last_byte = inode->i_size;
>
> - last_byte -= page_nr << PAGE_CACHE_SHIFT;
> - if (last_byte > PAGE_CACHE_SIZE)
> - last_byte = PAGE_CACHE_SIZE;
> + last_byte -= page_nr << PAGE_SHIFT;
> + if (last_byte > PAGE_SIZE)
> + last_byte = PAGE_SIZE;
> return last_byte;
> }
>
> @@ -85,13 +85,13 @@ static void exofs_check_page(struct page *page)
> unsigned chunk_size = exofs_chunk_size(dir);
> char *kaddr = page_address(page);
> unsigned offs, rec_len;
> - unsigned limit = PAGE_CACHE_SIZE;
> + unsigned limit = PAGE_SIZE;
> struct exofs_dir_entry *p;
> char *error;
>
> /* if the page is the last one in the directory */
> - if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
> - limit = dir->i_size & ~PAGE_CACHE_MASK;
> + if ((dir->i_size >> PAGE_SHIFT) == page->index) {
> + limit = dir->i_size & ~PAGE_MASK;
> if (limit & (chunk_size - 1))
> goto Ebadsize;
> if (!limit)
> @@ -138,7 +138,7 @@ bad_entry:
> EXOFS_ERR(
> "ERROR [exofs_check_page]: bad entry in directory(0x%lx): %s - "
> "offset=%lu, inode=0x%llu, rec_len=%d, name_len=%d\n",
> - dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
> + dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
> _LLU(le64_to_cpu(p->inode_no)),
> rec_len, p->name_len);
> goto fail;
> @@ -147,7 +147,7 @@ Eend:
> EXOFS_ERR("ERROR [exofs_check_page]: "
> "entry in directory(0x%lx) spans the page boundary"
> "offset=%lu, inode=0x%llx\n",
> - dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
> + dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
> _LLU(le64_to_cpu(p->inode_no)));
> fail:
> SetPageChecked(page);
> @@ -237,8 +237,8 @@ exofs_readdir(struct file *file, struct dir_context *ctx)
> {
> loff_t pos = ctx->pos;
> struct inode *inode = file_inode(file);
> - unsigned int offset = pos & ~PAGE_CACHE_MASK;
> - unsigned long n = pos >> PAGE_CACHE_SHIFT;
> + unsigned int offset = pos & ~PAGE_MASK;
> + unsigned long n = pos >> PAGE_SHIFT;
> unsigned long npages = dir_pages(inode);
> unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
> int need_revalidate = (file->f_version != inode->i_version);
> @@ -254,7 +254,7 @@ exofs_readdir(struct file *file, struct dir_context *ctx)
> if (IS_ERR(page)) {
> EXOFS_ERR("ERROR: bad page in directory(0x%lx)\n",
> inode->i_ino);
> - ctx->pos += PAGE_CACHE_SIZE - offset;
> + ctx->pos += PAGE_SIZE - offset;
> return PTR_ERR(page);
> }
> kaddr = page_address(page);
> @@ -262,7 +262,7 @@ exofs_readdir(struct file *file, struct dir_context *ctx)
> if (offset) {
> offset = exofs_validate_entry(kaddr, offset,
> chunk_mask);
> - ctx->pos = (n<<PAGE_CACHE_SHIFT) + offset;
> + ctx->pos = (n<<PAGE_SHIFT) + offset;
> }
> file->f_version = inode->i_version;
> need_revalidate = 0;
> @@ -449,7 +449,7 @@ int exofs_add_link(struct dentry *dentry, struct inode *inode)
> kaddr = page_address(page);
> dir_end = kaddr + exofs_last_byte(dir, n);
> de = (struct exofs_dir_entry *)kaddr;
> - kaddr += PAGE_CACHE_SIZE - reclen;
> + kaddr += PAGE_SIZE - reclen;
> while ((char *)de <= kaddr) {
> if ((char *)de == dir_end) {
> name_len = 0;
> @@ -602,7 +602,7 @@ int exofs_make_empty(struct inode *inode, struct inode *parent)
> kunmap_atomic(kaddr);
> err = exofs_commit_chunk(page, 0, chunk_size);
> fail:
> - page_cache_release(page);
> + put_page(page);
> return err;
> }
>
> diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
> index 9eaf595aeaf8..49e1bd00b4ec 100644
> --- a/fs/exofs/inode.c
> +++ b/fs/exofs/inode.c
> @@ -317,7 +317,7 @@ static int read_exec(struct page_collect *pcol)
>
> if (!pcol->ios) {
> int ret = ore_get_rw_state(&pcol->sbi->layout, &oi->oc, true,
> - pcol->pg_first << PAGE_CACHE_SHIFT,
> + pcol->pg_first << PAGE_SHIFT,
> pcol->length, &pcol->ios);
>
> if (ret)
> @@ -383,7 +383,7 @@ static int readpage_strip(void *data, struct page *page)
> struct inode *inode = pcol->inode;
> struct exofs_i_info *oi = exofs_i(inode);
> loff_t i_size = i_size_read(inode);
> - pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
> + pgoff_t end_index = i_size >> PAGE_SHIFT;
> size_t len;
> int ret;
>
> @@ -397,9 +397,9 @@ static int readpage_strip(void *data, struct page *page)
> pcol->that_locked_page = page;
>
> if (page->index < end_index)
> - len = PAGE_CACHE_SIZE;
> + len = PAGE_SIZE;
> else if (page->index == end_index)
> - len = i_size & ~PAGE_CACHE_MASK;
> + len = i_size & ~PAGE_MASK;
> else
> len = 0;
>
> @@ -442,8 +442,8 @@ try_again:
> goto fail;
> }
>
> - if (len != PAGE_CACHE_SIZE)
> - zero_user(page, len, PAGE_CACHE_SIZE - len);
> + if (len != PAGE_SIZE)
> + zero_user(page, len, PAGE_SIZE - len);
>
> EXOFS_DBGMSG2(" readpage_strip(0x%lx, 0x%lx) len=0x%zx\n",
> inode->i_ino, page->index, len);
> @@ -609,7 +609,7 @@ static void __r4w_put_page(void *priv, struct page *page)
>
> if ((pcol->that_locked_page != page) && (ZERO_PAGE(0) != page)) {
> EXOFS_DBGMSG2("index=0x%lx\n", page->index);
> - page_cache_release(page);
> + put_page(page);
> return;
> }
> EXOFS_DBGMSG2("that_locked_page index=0x%lx\n",
> @@ -633,7 +633,7 @@ static int write_exec(struct page_collect *pcol)
>
> BUG_ON(pcol->ios);
> ret = ore_get_rw_state(&pcol->sbi->layout, &oi->oc, false,
> - pcol->pg_first << PAGE_CACHE_SHIFT,
> + pcol->pg_first << PAGE_SHIFT,
> pcol->length, &pcol->ios);
> if (unlikely(ret))
> goto err;
> @@ -696,7 +696,7 @@ static int writepage_strip(struct page *page,
> struct inode *inode = pcol->inode;
> struct exofs_i_info *oi = exofs_i(inode);
> loff_t i_size = i_size_read(inode);
> - pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
> + pgoff_t end_index = i_size >> PAGE_SHIFT;
> size_t len;
> int ret;
>
> @@ -708,9 +708,9 @@ static int writepage_strip(struct page *page,
>
> if (page->index < end_index)
> /* in this case, the page is within the limits of the file */
> - len = PAGE_CACHE_SIZE;
> + len = PAGE_SIZE;
> else {
> - len = i_size & ~PAGE_CACHE_MASK;
> + len = i_size & ~PAGE_MASK;
>
> if (page->index > end_index || !len) {
> /* in this case, the page is outside the limits
> @@ -790,10 +790,10 @@ static int exofs_writepages(struct address_space *mapping,
> long start, end, expected_pages;
> int ret;
>
> - start = wbc->range_start >> PAGE_CACHE_SHIFT;
> + start = wbc->range_start >> PAGE_SHIFT;
> end = (wbc->range_end == LLONG_MAX) ?
> start + mapping->nrpages :
> - wbc->range_end >> PAGE_CACHE_SHIFT;
> + wbc->range_end >> PAGE_SHIFT;
>
> if (start || end)
> expected_pages = end - start + 1;
> @@ -881,15 +881,15 @@ int exofs_write_begin(struct file *file, struct address_space *mapping,
> }
>
> /* read modify write */
> - if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
> + if (!PageUptodate(page) && (len != PAGE_SIZE)) {
> loff_t i_size = i_size_read(mapping->host);
> - pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
> + pgoff_t end_index = i_size >> PAGE_SHIFT;
> size_t rlen;
>
> if (page->index < end_index)
> - rlen = PAGE_CACHE_SIZE;
> + rlen = PAGE_SIZE;
> else if (page->index == end_index)
> - rlen = i_size & ~PAGE_CACHE_MASK;
> + rlen = i_size & ~PAGE_MASK;
> else
> rlen = 0;
>
> diff --git a/fs/exofs/namei.c b/fs/exofs/namei.c
> index c20d77df2679..622a686bb08b 100644
> --- a/fs/exofs/namei.c
> +++ b/fs/exofs/namei.c
> @@ -292,11 +292,11 @@ static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
> out_dir:
> if (dir_de) {
> kunmap(dir_page);
> - page_cache_release(dir_page);
> + put_page(dir_page);
> }
> out_old:
> kunmap(old_page);
> - page_cache_release(old_page);
> + put_page(old_page);
> out:
> return err;
> }
>
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