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/afs/dir.c b/fs/afs/dir.c
index e10e1778..5fda2bc 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -181,7 +181,7 @@
 static inline void afs_dir_put_page(struct page *page)
 {
 	kunmap(page);
-	page_cache_release(page);
+	put_page(page);
 }
 
 /*
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 999bc3c..6344aee 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -164,7 +164,7 @@
 		_debug("cache said ENOBUFS");
 	default:
 	go_on:
-		offset = page->index << PAGE_CACHE_SHIFT;
+		offset = page->index << PAGE_SHIFT;
 		len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
 
 		/* read the contents of the file from the server into the
@@ -319,7 +319,7 @@
 	BUG_ON(!PageLocked(page));
 
 	/* we clean up only if the entire page is being invalidated */
-	if (offset == 0 && length == PAGE_CACHE_SIZE) {
+	if (offset == 0 && length == PAGE_SIZE) {
 #ifdef CONFIG_AFS_FSCACHE
 		if (PageFsCache(page)) {
 			struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index ccd0b21..81dd075 100644
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -93,7 +93,7 @@
 
 	kunmap(page);
 out_free:
-	page_cache_release(page);
+	put_page(page);
 out:
 	_leave(" = %d", ret);
 	return ret;
@@ -189,7 +189,7 @@
 		buf = kmap_atomic(page);
 		memcpy(devname, buf, size);
 		kunmap_atomic(buf);
-		page_cache_release(page);
+		put_page(page);
 		page = NULL;
 	}
 
@@ -211,7 +211,7 @@
 	return mnt;
 
 error:
-	page_cache_release(page);
+	put_page(page);
 error_no_page:
 	free_page((unsigned long) options);
 error_no_options:
diff --git a/fs/afs/super.c b/fs/afs/super.c
index 81afefe..fbdb022 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -315,8 +315,8 @@
 	_enter("");
 
 	/* fill in the superblock */
-	sb->s_blocksize		= PAGE_CACHE_SIZE;
-	sb->s_blocksize_bits	= PAGE_CACHE_SHIFT;
+	sb->s_blocksize		= PAGE_SIZE;
+	sb->s_blocksize_bits	= PAGE_SHIFT;
 	sb->s_magic		= AFS_FS_MAGIC;
 	sb->s_op		= &afs_super_ops;
 	sb->s_bdi		= &as->volume->bdi;
diff --git a/fs/afs/write.c b/fs/afs/write.c
index dfef94f..65de439 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -93,10 +93,10 @@
 	_enter(",,%llu", (unsigned long long)pos);
 
 	i_size = i_size_read(&vnode->vfs_inode);
-	if (pos + PAGE_CACHE_SIZE > i_size)
+	if (pos + PAGE_SIZE > i_size)
 		len = i_size - pos;
 	else
-		len = PAGE_CACHE_SIZE;
+		len = PAGE_SIZE;
 
 	ret = afs_vnode_fetch_data(vnode, key, pos, len, page);
 	if (ret < 0) {
@@ -123,9 +123,9 @@
 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
 	struct page *page;
 	struct key *key = file->private_data;
-	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+	unsigned from = pos & (PAGE_SIZE - 1);
 	unsigned to = from + len;
-	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	pgoff_t index = pos >> PAGE_SHIFT;
 	int ret;
 
 	_enter("{%x:%u},{%lx},%u,%u",
@@ -151,8 +151,8 @@
 	*pagep = page;
 	/* page won't leak in error case: it eventually gets cleaned off LRU */
 
-	if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) {
-		ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page);
+	if (!PageUptodate(page) && len != PAGE_SIZE) {
+		ret = afs_fill_page(vnode, key, index << PAGE_SHIFT, page);
 		if (ret < 0) {
 			kfree(candidate);
 			_leave(" = %d [prep]", ret);
@@ -266,7 +266,7 @@
 	if (PageDirty(page))
 		_debug("dirtied");
 	unlock_page(page);
-	page_cache_release(page);
+	put_page(page);
 
 	return copied;
 }
@@ -480,7 +480,7 @@
 
 		if (page->index > end) {
 			*_next = index;
-			page_cache_release(page);
+			put_page(page);
 			_leave(" = 0 [%lx]", *_next);
 			return 0;
 		}
@@ -494,7 +494,7 @@
 
 		if (page->mapping != mapping) {
 			unlock_page(page);
-			page_cache_release(page);
+			put_page(page);
 			continue;
 		}
 
@@ -515,7 +515,7 @@
 
 		ret = afs_write_back_from_locked_page(wb, page);
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		if (ret < 0) {
 			_leave(" = %d", ret);
 			return ret;
@@ -551,13 +551,13 @@
 						    &next);
 		mapping->writeback_index = next;
 	} else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
-		end = (pgoff_t)(LLONG_MAX >> PAGE_CACHE_SHIFT);
+		end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT);
 		ret = afs_writepages_region(mapping, wbc, 0, end, &next);
 		if (wbc->nr_to_write > 0)
 			mapping->writeback_index = next;
 	} else {
-		start = wbc->range_start >> PAGE_CACHE_SHIFT;
-		end = wbc->range_end >> PAGE_CACHE_SHIFT;
+		start = wbc->range_start >> PAGE_SHIFT;
+		end = wbc->range_end >> PAGE_SHIFT;
 		ret = afs_writepages_region(mapping, wbc, start, end, &next);
 	}