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, 19 insertions, 19 deletions

diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 82990b8f872b..88d274e8ecf2 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -59,7 +59,7 @@ static struct list_head *zlib_alloc_workspace(void)
 	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
 			zlib_inflate_workspacesize());
 	workspace->strm.workspace = vmalloc(workspacesize);
-	workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
+	workspace->buf = kmalloc(PAGE_SIZE, GFP_NOFS);
 	if (!workspace->strm.workspace || !workspace->buf)
 		goto fail;
 
@@ -103,7 +103,7 @@ static int zlib_compress_pages(struct list_head *ws,
 	workspace->strm.total_in = 0;
 	workspace->strm.total_out = 0;
 
-	in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
+	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
 	data_in = kmap(in_page);
 
 	out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
@@ -117,8 +117,8 @@ static int zlib_compress_pages(struct list_head *ws,
 
 	workspace->strm.next_in = data_in;
 	workspace->strm.next_out = cpage_out;
-	workspace->strm.avail_out = PAGE_CACHE_SIZE;
-	workspace->strm.avail_in = min(len, PAGE_CACHE_SIZE);
+	workspace->strm.avail_out = PAGE_SIZE;
+	workspace->strm.avail_in = min(len, PAGE_SIZE);
 
 	while (workspace->strm.total_in < len) {
 		ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
@@ -156,7 +156,7 @@ static int zlib_compress_pages(struct list_head *ws,
 			cpage_out = kmap(out_page);
 			pages[nr_pages] = out_page;
 			nr_pages++;
-			workspace->strm.avail_out = PAGE_CACHE_SIZE;
+			workspace->strm.avail_out = PAGE_SIZE;
 			workspace->strm.next_out = cpage_out;
 		}
 		/* we're all done */
@@ -170,14 +170,14 @@ static int zlib_compress_pages(struct list_head *ws,
 
 			bytes_left = len - workspace->strm.total_in;
 			kunmap(in_page);
-			page_cache_release(in_page);
+			put_page(in_page);
 
-			start += PAGE_CACHE_SIZE;
+			start += PAGE_SIZE;
 			in_page = find_get_page(mapping,
-						start >> PAGE_CACHE_SHIFT);
+						start >> PAGE_SHIFT);
 			data_in = kmap(in_page);
 			workspace->strm.avail_in = min(bytes_left,
-							   PAGE_CACHE_SIZE);
+							   PAGE_SIZE);
 			workspace->strm.next_in = data_in;
 		}
 	}
@@ -205,7 +205,7 @@ out:
 
 	if (in_page) {
 		kunmap(in_page);
-		page_cache_release(in_page);
+		put_page(in_page);
 	}
 	return ret;
 }
@@ -223,18 +223,18 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
 	size_t total_out = 0;
 	unsigned long page_in_index = 0;
 	unsigned long page_out_index = 0;
-	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_CACHE_SIZE);
+	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
 	unsigned long buf_start;
 	unsigned long pg_offset;
 
 	data_in = kmap(pages_in[page_in_index]);
 	workspace->strm.next_in = data_in;
-	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
+	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
 	workspace->strm.total_in = 0;
 
 	workspace->strm.total_out = 0;
 	workspace->strm.next_out = workspace->buf;
-	workspace->strm.avail_out = PAGE_CACHE_SIZE;
+	workspace->strm.avail_out = PAGE_SIZE;
 	pg_offset = 0;
 
 	/* If it's deflate, and it's got no preset dictionary, then
@@ -274,7 +274,7 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
 		}
 
 		workspace->strm.next_out = workspace->buf;
-		workspace->strm.avail_out = PAGE_CACHE_SIZE;
+		workspace->strm.avail_out = PAGE_SIZE;
 
 		if (workspace->strm.avail_in == 0) {
 			unsigned long tmp;
@@ -288,7 +288,7 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
 			workspace->strm.next_in = data_in;
 			tmp = srclen - workspace->strm.total_in;
 			workspace->strm.avail_in = min(tmp,
-							   PAGE_CACHE_SIZE);
+							   PAGE_SIZE);
 		}
 	}
 	if (ret != Z_STREAM_END)
@@ -325,7 +325,7 @@ static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 	workspace->strm.total_in = 0;
 
 	workspace->strm.next_out = workspace->buf;
-	workspace->strm.avail_out = PAGE_CACHE_SIZE;
+	workspace->strm.avail_out = PAGE_SIZE;
 	workspace->strm.total_out = 0;
 	/* If it's deflate, and it's got no preset dictionary, then
 	   we can tell zlib to skip the adler32 check. */
@@ -368,8 +368,8 @@ static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 		else
 			buf_offset = 0;
 
-		bytes = min(PAGE_CACHE_SIZE - pg_offset,
-			    PAGE_CACHE_SIZE - buf_offset);
+		bytes = min(PAGE_SIZE - pg_offset,
+			    PAGE_SIZE - buf_offset);
 		bytes = min(bytes, bytes_left);
 
 		kaddr = kmap_atomic(dest_page);
@@ -380,7 +380,7 @@ static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
 		bytes_left -= bytes;
 next:
 		workspace->strm.next_out = workspace->buf;
-		workspace->strm.avail_out = PAGE_CACHE_SIZE;
+		workspace->strm.avail_out = PAGE_SIZE;
 	}
 
 	if (ret != Z_STREAM_END && bytes_left != 0)