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 <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Ron Minnich <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
---
 fs/9p/vfs_addr.c  | 18 +++++++++---------
 fs/9p/vfs_file.c  |  4 ++--
 fs/9p/vfs_super.c |  2 +-
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index e9e04376c52c..ac9225e86bf3 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -153,7 +153,7 @@ static void v9fs_invalidate_page(struct page *page, 
unsigned int offset,
         * If called with zero offset, we should release
         * the private state assocated with the page
         */
-       if (offset == 0 && length == PAGE_CACHE_SIZE)
+       if (offset == 0 && length == PAGE_SIZE)
                v9fs_fscache_invalidate_page(page);
 }
 
@@ -166,10 +166,10 @@ static int v9fs_vfs_writepage_locked(struct page *page)
        struct bio_vec bvec;
        int err, len;
 
-       if (page->index == size >> PAGE_CACHE_SHIFT)
-               len = size & ~PAGE_CACHE_MASK;
+       if (page->index == size >> PAGE_SHIFT)
+               len = size & ~PAGE_MASK;
        else
-               len = PAGE_CACHE_SIZE;
+               len = PAGE_SIZE;
 
        bvec.bv_page = page;
        bvec.bv_offset = 0;
@@ -271,7 +271,7 @@ static int v9fs_write_begin(struct file *filp, struct 
address_space *mapping,
        int retval = 0;
        struct page *page;
        struct v9fs_inode *v9inode;
-       pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+       pgoff_t index = pos >> PAGE_SHIFT;
        struct inode *inode = mapping->host;
 
 
@@ -288,11 +288,11 @@ start:
        if (PageUptodate(page))
                goto out;
 
-       if (len == PAGE_CACHE_SIZE)
+       if (len == PAGE_SIZE)
                goto out;
 
        retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
-       page_cache_release(page);
+       put_page(page);
        if (!retval)
                goto start;
 out:
@@ -313,7 +313,7 @@ static int v9fs_write_end(struct file *filp, struct 
address_space *mapping,
                /*
                 * zero out the rest of the area
                 */
-               unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+               unsigned from = pos & (PAGE_SIZE - 1);
 
                zero_user(page, from + copied, len - copied);
                flush_dcache_page(page);
@@ -331,7 +331,7 @@ static int v9fs_write_end(struct file *filp, struct 
address_space *mapping,
        }
        set_page_dirty(page);
        unlock_page(page);
-       page_cache_release(page);
+       put_page(page);
 
        return copied;
 }
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index eadc894faea2..b84c291ba1eb 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -421,8 +421,8 @@ v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter 
*from)
                struct inode *inode = file_inode(file);
                loff_t i_size;
                unsigned long pg_start, pg_end;
-               pg_start = origin >> PAGE_CACHE_SHIFT;
-               pg_end = (origin + retval - 1) >> PAGE_CACHE_SHIFT;
+               pg_start = origin >> PAGE_SHIFT;
+               pg_end = (origin + retval - 1) >> PAGE_SHIFT;
                if (inode->i_mapping && inode->i_mapping->nrpages)
                        invalidate_inode_pages2_range(inode->i_mapping,
                                                      pg_start, pg_end);
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index bf495cedec26..de3ed8629196 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -87,7 +87,7 @@ v9fs_fill_super(struct super_block *sb, struct 
v9fs_session_info *v9ses,
                sb->s_op = &v9fs_super_ops;
        sb->s_bdi = &v9ses->bdi;
        if (v9ses->cache)
-               sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024)/PAGE_CACHE_SIZE;
+               sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024)/PAGE_SIZE;
 
        sb->s_flags |= MS_ACTIVE | MS_DIRSYNC | MS_NOATIME;
        if (!v9ses->cache)
-- 
2.7.0

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