mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

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>;

 - <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();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 12 insertions, 12 deletions

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index e9e0437..ac9225e 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 eadc894..b84c291 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 bf495ce..de3ed86 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)