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>

fs/cramfs/inode.c

@@ -152,7 +152,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb,
  */
 #define BLKS_PER_BUF_SHIFT	(2)
 #define BLKS_PER_BUF		(1 << BLKS_PER_BUF_SHIFT)
-#define BUFFER_SIZE		(BLKS_PER_BUF*PAGE_CACHE_SIZE)
+#define BUFFER_SIZE		(BLKS_PER_BUF*PAGE_SIZE)
 
 static unsigned char read_buffers[READ_BUFFERS][BUFFER_SIZE];
 static unsigned buffer_blocknr[READ_BUFFERS];
@@ -173,8 +173,8 @@ static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned i
 
 	if (!len)
 		return NULL;
-	blocknr = offset >> PAGE_CACHE_SHIFT;
-	offset &= PAGE_CACHE_SIZE - 1;
+	blocknr = offset >> PAGE_SHIFT;
+	offset &= PAGE_SIZE - 1;
 
 	/* Check if an existing buffer already has the data.. */
 	for (i = 0; i < READ_BUFFERS; i++) {
@@ -184,14 +184,14 @@ static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned i
 			continue;
 		if (blocknr < buffer_blocknr[i])
 			continue;
-		blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_CACHE_SHIFT;
+		blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_SHIFT;
 		blk_offset += offset;
 		if (blk_offset + len > BUFFER_SIZE)
 			continue;
 		return read_buffers[i] + blk_offset;
 	}
 
-	devsize = mapping->host->i_size >> PAGE_CACHE_SHIFT;
+	devsize = mapping->host->i_size >> PAGE_SHIFT;
 
 	/* Ok, read in BLKS_PER_BUF pages completely first. */
 	for (i = 0; i < BLKS_PER_BUF; i++) {
@@ -213,7 +213,7 @@ static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned i
 			wait_on_page_locked(page);
 			if (!PageUptodate(page)) {
 				/* asynchronous error */
-				page_cache_release(page);
+				put_page(page);
 				pages[i] = NULL;
 			}
 		}
@@ -229,12 +229,12 @@ static void *cramfs_read(struct super_block *sb, unsigned int offset, unsigned i
 		struct page *page = pages[i];
 
 		if (page) {
-			memcpy(data, kmap(page), PAGE_CACHE_SIZE);
+			memcpy(data, kmap(page), PAGE_SIZE);
 			kunmap(page);
-			page_cache_release(page);
+			put_page(page);
 		} else
-			memset(data, 0, PAGE_CACHE_SIZE);
-		data += PAGE_CACHE_SIZE;
+			memset(data, 0, PAGE_SIZE);
+		data += PAGE_SIZE;
 	}
 	return read_buffers[buffer] + offset;
 }
@@ -353,7 +353,7 @@ static int cramfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 
 	buf->f_type = CRAMFS_MAGIC;
-	buf->f_bsize = PAGE_CACHE_SIZE;
+	buf->f_bsize = PAGE_SIZE;
 	buf->f_blocks = CRAMFS_SB(sb)->blocks;
 	buf->f_bfree = 0;
 	buf->f_bavail = 0;
@@ -496,7 +496,7 @@ static int cramfs_readpage(struct file *file, struct page *page)
 	int bytes_filled;
 	void *pgdata;
 
-	maxblock = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	maxblock = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	bytes_filled = 0;
 	pgdata = kmap(page);
 
@@ -516,14 +516,14 @@ static int cramfs_readpage(struct file *file, struct page *page)
 
 		if (compr_len == 0)
 			; /* hole */
-		else if (unlikely(compr_len > (PAGE_CACHE_SIZE << 1))) {
+		else if (unlikely(compr_len > (PAGE_SIZE << 1))) {
 			pr_err("bad compressed blocksize %u\n",
 				compr_len);
 			goto err;
 		} else {
 			mutex_lock(&read_mutex);
 			bytes_filled = cramfs_uncompress_block(pgdata,
-				 PAGE_CACHE_SIZE,
+				 PAGE_SIZE,
 				 cramfs_read(sb, start_offset, compr_len),
 				 compr_len);
 			mutex_unlock(&read_mutex);
@@ -532,7 +532,7 @@ static int cramfs_readpage(struct file *file, struct page *page)
 		}
 	}
 
-	memset(pgdata + bytes_filled, 0, PAGE_CACHE_SIZE - bytes_filled);
+	memset(pgdata + bytes_filled, 0, PAGE_SIZE - bytes_filled);
 	flush_dcache_page(page);
 	kunmap(page);
 	SetPageUptodate(page);