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>

1 files changed, 12 insertions, 12 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 0ca80b2af420..f3fa82ce9b70 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -25,7 +25,7 @@ int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
 {
 	struct inode *inode = d_inode(dentry);
 	generic_fillattr(inode, stat);
-	stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9);
+	stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9);
 	return 0;
 }
 EXPORT_SYMBOL(simple_getattr);
@@ -33,7 +33,7 @@ EXPORT_SYMBOL(simple_getattr);
 int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	buf->f_type = dentry->d_sb->s_magic;
-	buf->f_bsize = PAGE_CACHE_SIZE;
+	buf->f_bsize = PAGE_SIZE;
 	buf->f_namelen = NAME_MAX;
 	return 0;
 }
@@ -395,7 +395,7 @@ int simple_write_begin(struct file *file, struct address_space *mapping,
 	struct page *page;
 	pgoff_t index;
 
-	index = pos >> PAGE_CACHE_SHIFT;
+	index = pos >> PAGE_SHIFT;
 
 	page = grab_cache_page_write_begin(mapping, index, flags);
 	if (!page)
@@ -403,10 +403,10 @@ int simple_write_begin(struct file *file, struct address_space *mapping,
 
 	*pagep = page;
 
-	if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
-		unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+	if (!PageUptodate(page) && (len != PAGE_SIZE)) {
+		unsigned from = pos & (PAGE_SIZE - 1);
 
-		zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE);
+		zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
 	}
 	return 0;
 }
@@ -442,7 +442,7 @@ int simple_write_end(struct file *file, struct address_space *mapping,
 
 	/* zero the stale part of the page if we did a short copy */
 	if (copied < len) {
-		unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+		unsigned from = pos & (PAGE_SIZE - 1);
 
 		zero_user(page, from + copied, len - copied);
 	}
@@ -458,7 +458,7 @@ int simple_write_end(struct file *file, struct address_space *mapping,
 
 	set_page_dirty(page);
 	unlock_page(page);
-	page_cache_release(page);
+	put_page(page);
 
 	return copied;
 }
@@ -477,8 +477,8 @@ int simple_fill_super(struct super_block *s, unsigned long magic,
 	struct dentry *dentry;
 	int i;
 
-	s->s_blocksize = PAGE_CACHE_SIZE;
-	s->s_blocksize_bits = PAGE_CACHE_SHIFT;
+	s->s_blocksize = PAGE_SIZE;
+	s->s_blocksize_bits = PAGE_SHIFT;
 	s->s_magic = magic;
 	s->s_op = &simple_super_operations;
 	s->s_time_gran = 1;
@@ -994,12 +994,12 @@ int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
 {
 	u64 last_fs_block = num_blocks - 1;
 	u64 last_fs_page =
-		last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits);
+		last_fs_block >> (PAGE_SHIFT - blocksize_bits);
 
 	if (unlikely(num_blocks == 0))
 		return 0;
 
-	if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT))
+	if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
 		return -EINVAL;
 
 	if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||