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, 8 insertions, 8 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 19b7bf4284ee..8d358c547c59 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4449,9 +4449,9 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 	struct page *page;
 	char *addr;
 	struct btrfs_key key;
-	pgoff_t index = offset >> PAGE_CACHE_SHIFT;
+	pgoff_t index = offset >> PAGE_SHIFT;
 	pgoff_t last_index;
-	unsigned pg_offset = offset & ~PAGE_CACHE_MASK;
+	unsigned pg_offset = offset & ~PAGE_MASK;
 	ssize_t ret = 0;
 
 	key.objectid = sctx->cur_ino;
@@ -4471,7 +4471,7 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 	if (len == 0)
 		goto out;
 
-	last_index = (offset + len - 1) >> PAGE_CACHE_SHIFT;
+	last_index = (offset + len - 1) >> PAGE_SHIFT;
 
 	/* initial readahead */
 	memset(&sctx->ra, 0, sizeof(struct file_ra_state));
@@ -4481,7 +4481,7 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 
 	while (index <= last_index) {
 		unsigned cur_len = min_t(unsigned, len,
-					 PAGE_CACHE_SIZE - pg_offset);
+					 PAGE_SIZE - pg_offset);
 		page = find_or_create_page(inode->i_mapping, index, GFP_KERNEL);
 		if (!page) {
 			ret = -ENOMEM;
@@ -4493,7 +4493,7 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 			lock_page(page);
 			if (!PageUptodate(page)) {
 				unlock_page(page);
-				page_cache_release(page);
+				put_page(page);
 				ret = -EIO;
 				break;
 			}
@@ -4503,7 +4503,7 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
 		memcpy(sctx->read_buf + ret, addr + pg_offset, cur_len);
 		kunmap(page);
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		index++;
 		pg_offset = 0;
 		len -= cur_len;
@@ -4804,7 +4804,7 @@ static int clone_range(struct send_ctx *sctx,
 		type = btrfs_file_extent_type(leaf, ei);
 		if (type == BTRFS_FILE_EXTENT_INLINE) {
 			ext_len = btrfs_file_extent_inline_len(leaf, slot, ei);
-			ext_len = PAGE_CACHE_ALIGN(ext_len);
+			ext_len = PAGE_ALIGN(ext_len);
 		} else {
 			ext_len = btrfs_file_extent_num_bytes(leaf, ei);
 		}
@@ -4886,7 +4886,7 @@ static int send_write_or_clone(struct send_ctx *sctx,
 		 * but there may be items after this page.  Make
 		 * sure to send the whole thing
 		 */
-		len = PAGE_CACHE_ALIGN(len);
+		len = PAGE_ALIGN(len);
 	} else {
 		len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
 	}