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>
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index a3eb316..b60e015 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -80,7 +80,7 @@
 static struct kmem_cache *metapage_cache;
 static mempool_t *metapage_mempool;
 
-#define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE)
+#define MPS_PER_PAGE (PAGE_SIZE >> L2PSIZE)
 
 #if MPS_PER_PAGE > 1
 
@@ -316,7 +316,7 @@
 	struct metapage *mp;
 	unsigned int offset;
 
-	for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
+	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
 		mp = page_to_mp(page, offset);
 		if (mp && test_bit(META_io, &mp->flag)) {
 			if (mp->lsn)
@@ -366,12 +366,12 @@
 	int bad_blocks = 0;
 
 	page_start = (sector_t)page->index <<
-		     (PAGE_CACHE_SHIFT - inode->i_blkbits);
+		     (PAGE_SHIFT - inode->i_blkbits);
 	BUG_ON(!PageLocked(page));
 	BUG_ON(PageWriteback(page));
 	set_page_writeback(page);
 
-	for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
+	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
 		mp = page_to_mp(page, offset);
 
 		if (!mp || !test_bit(META_dirty, &mp->flag))
@@ -416,7 +416,7 @@
 			bio = NULL;
 		} else
 			inc_io(page);
-		xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
+		xlen = (PAGE_SIZE - offset) >> inode->i_blkbits;
 		pblock = metapage_get_blocks(inode, lblock, &xlen);
 		if (!pblock) {
 			printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
@@ -485,7 +485,7 @@
 	struct inode *inode = page->mapping->host;
 	struct bio *bio = NULL;
 	int block_offset;
-	int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
+	int blocks_per_page = PAGE_SIZE >> inode->i_blkbits;
 	sector_t page_start;	/* address of page in fs blocks */
 	sector_t pblock;
 	int xlen;
@@ -494,7 +494,7 @@
 
 	BUG_ON(!PageLocked(page));
 	page_start = (sector_t)page->index <<
-		     (PAGE_CACHE_SHIFT - inode->i_blkbits);
+		     (PAGE_SHIFT - inode->i_blkbits);
 
 	block_offset = 0;
 	while (block_offset < blocks_per_page) {
@@ -542,7 +542,7 @@
 	int ret = 1;
 	int offset;
 
-	for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
+	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
 		mp = page_to_mp(page, offset);
 
 		if (!mp)
@@ -568,7 +568,7 @@
 static void metapage_invalidatepage(struct page *page, unsigned int offset,
 				    unsigned int length)
 {
-	BUG_ON(offset || length < PAGE_CACHE_SIZE);
+	BUG_ON(offset || length < PAGE_SIZE);
 
 	BUG_ON(PageWriteback(page));
 
@@ -599,10 +599,10 @@
 		 inode->i_ino, lblock, absolute);
 
 	l2bsize = inode->i_blkbits;
-	l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
+	l2BlocksPerPage = PAGE_SHIFT - l2bsize;
 	page_index = lblock >> l2BlocksPerPage;
 	page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
-	if ((page_offset + size) > PAGE_CACHE_SIZE) {
+	if ((page_offset + size) > PAGE_SIZE) {
 		jfs_err("MetaData crosses page boundary!!");
 		jfs_err("lblock = %lx, size  = %d", lblock, size);
 		dump_stack();
@@ -621,7 +621,7 @@
 		mapping = inode->i_mapping;
 	}
 
-	if (new && (PSIZE == PAGE_CACHE_SIZE)) {
+	if (new && (PSIZE == PAGE_SIZE)) {
 		page = grab_cache_page(mapping, page_index);
 		if (!page) {
 			jfs_err("grab_cache_page failed!");
@@ -693,7 +693,7 @@
 void grab_metapage(struct metapage * mp)
 {
 	jfs_info("grab_metapage: mp = 0x%p", mp);
-	page_cache_get(mp->page);
+	get_page(mp->page);
 	lock_page(mp->page);
 	mp->count++;
 	lock_metapage(mp);
@@ -706,12 +706,12 @@
 	jfs_info("force_metapage: mp = 0x%p", mp);
 	set_bit(META_forcewrite, &mp->flag);
 	clear_bit(META_sync, &mp->flag);
-	page_cache_get(page);
+	get_page(page);
 	lock_page(page);
 	set_page_dirty(page);
 	write_one_page(page, 1);
 	clear_bit(META_forcewrite, &mp->flag);
-	page_cache_release(page);
+	put_page(page);
 }
 
 void hold_metapage(struct metapage *mp)
@@ -726,7 +726,7 @@
 		unlock_page(mp->page);
 		return;
 	}
-	page_cache_get(mp->page);
+	get_page(mp->page);
 	mp->count++;
 	lock_metapage(mp);
 	unlock_page(mp->page);
@@ -746,7 +746,7 @@
 	assert(mp->count);
 	if (--mp->count || mp->nohomeok) {
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		return;
 	}
 
@@ -764,13 +764,13 @@
 	drop_metapage(page, mp);
 
 	unlock_page(page);
-	page_cache_release(page);
+	put_page(page);
 }
 
 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
 {
 	sector_t lblock;
-	int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
+	int l2BlocksPerPage = PAGE_SHIFT - ip->i_blkbits;
 	int BlocksPerPage = 1 << l2BlocksPerPage;
 	/* All callers are interested in block device's mapping */
 	struct address_space *mapping =
@@ -788,7 +788,7 @@
 		page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
 		if (!page)
 			continue;
-		for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
+		for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
 			mp = page_to_mp(page, offset);
 			if (!mp)
 				continue;
@@ -803,7 +803,7 @@
 				remove_from_logsync(mp);
 		}
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 	}
 }