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>

3 files changed, 30 insertions, 30 deletions

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 065c88f..1a9c664 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -121,7 +121,7 @@ static int do_readpage(struct page *page)
 	if (block >= beyond) {
 		/* Reading beyond inode */
 		SetPageChecked(page);
-		memset(addr, 0, PAGE_CACHE_SIZE);
+		memset(addr, 0, PAGE_SIZE);
 		goto out;
 	}
 
@@ -223,7 +223,7 @@ static int write_begin_slow(struct address_space *mapping,
 {
 	struct inode *inode = mapping->host;
 	struct ubifs_info *c = inode->i_sb->s_fs_info;
-	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	pgoff_t index = pos >> PAGE_SHIFT;
 	struct ubifs_budget_req req = { .new_page = 1 };
 	int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
 	struct page *page;
@@ -254,13 +254,13 @@ static int write_begin_slow(struct address_space *mapping,
 	}
 
 	if (!PageUptodate(page)) {
-		if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE)
+		if (!(pos & ~PAGE_MASK) && len == PAGE_SIZE)
 			SetPageChecked(page);
 		else {
 			err = do_readpage(page);
 			if (err) {
 				unlock_page(page);
-				page_cache_release(page);
+				put_page(page);
 				ubifs_release_budget(c, &req);
 				return err;
 			}
@@ -428,7 +428,7 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 	struct inode *inode = mapping->host;
 	struct ubifs_info *c = inode->i_sb->s_fs_info;
 	struct ubifs_inode *ui = ubifs_inode(inode);
-	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	pgoff_t index = pos >> PAGE_SHIFT;
 	int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
 	int skipped_read = 0;
 	struct page *page;
@@ -446,7 +446,7 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 
 	if (!PageUptodate(page)) {
 		/* The page is not loaded from the flash */
-		if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE) {
+		if (!(pos & ~PAGE_MASK) && len == PAGE_SIZE) {
 			/*
 			 * We change whole page so no need to load it. But we
 			 * do not know whether this page exists on the media or
@@ -462,7 +462,7 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 			err = do_readpage(page);
 			if (err) {
 				unlock_page(page);
-				page_cache_release(page);
+				put_page(page);
 				return err;
 			}
 		}
@@ -494,7 +494,7 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 			mutex_unlock(&ui->ui_mutex);
 		}
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 
 		return write_begin_slow(mapping, pos, len, pagep, flags);
 	}
@@ -549,7 +549,7 @@ static int ubifs_write_end(struct file *file, struct address_space *mapping,
 	dbg_gen("ino %lu, pos %llu, pg %lu, len %u, copied %d, i_size %lld",
 		inode->i_ino, pos, page->index, len, copied, inode->i_size);
 
-	if (unlikely(copied < len && len == PAGE_CACHE_SIZE)) {
+	if (unlikely(copied < len && len == PAGE_SIZE)) {
 		/*
 		 * VFS copied less data to the page that it intended and
 		 * declared in its '->write_begin()' call via the @len
@@ -593,7 +593,7 @@ static int ubifs_write_end(struct file *file, struct address_space *mapping,
 
 out:
 	unlock_page(page);
-	page_cache_release(page);
+	put_page(page);
 	return copied;
 }
 
@@ -621,10 +621,10 @@ static int populate_page(struct ubifs_info *c, struct page *page,
 
 	addr = zaddr = kmap(page);
 
-	end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
+	end_index = (i_size - 1) >> PAGE_SHIFT;
 	if (!i_size || page->index > end_index) {
 		hole = 1;
-		memset(addr, 0, PAGE_CACHE_SIZE);
+		memset(addr, 0, PAGE_SIZE);
 		goto out_hole;
 	}
 
@@ -673,7 +673,7 @@ static int populate_page(struct ubifs_info *c, struct page *page,
 	}
 
 	if (end_index == page->index) {
-		int len = i_size & (PAGE_CACHE_SIZE - 1);
+		int len = i_size & (PAGE_SIZE - 1);
 
 		if (len && len < read)
 			memset(zaddr + len, 0, read - len);
@@ -773,7 +773,7 @@ static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,
 	isize = i_size_read(inode);
 	if (isize == 0)
 		goto out_free;
-	end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
+	end_index = ((isize - 1) >> PAGE_SHIFT);
 
 	for (page_idx = 1; page_idx < page_cnt; page_idx++) {
 		pgoff_t page_offset = offset + page_idx;
@@ -788,7 +788,7 @@ static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,
 		if (!PageUptodate(page))
 			err = populate_page(c, page, bu, &n);
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		if (err)
 			break;
 	}
@@ -905,7 +905,7 @@ static int do_writepage(struct page *page, int len)
 #ifdef UBIFS_DEBUG
 	struct ubifs_inode *ui = ubifs_inode(inode);
 	spin_lock(&ui->ui_lock);
-	ubifs_assert(page->index <= ui->synced_i_size >> PAGE_CACHE_SHIFT);
+	ubifs_assert(page->index <= ui->synced_i_size >> PAGE_SHIFT);
 	spin_unlock(&ui->ui_lock);
 #endif
 
@@ -1001,8 +1001,8 @@ static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
 	struct inode *inode = page->mapping->host;
 	struct ubifs_inode *ui = ubifs_inode(inode);
 	loff_t i_size =  i_size_read(inode), synced_i_size;
-	pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
-	int err, len = i_size & (PAGE_CACHE_SIZE - 1);
+	pgoff_t end_index = i_size >> PAGE_SHIFT;
+	int err, len = i_size & (PAGE_SIZE - 1);
 	void *kaddr;
 
 	dbg_gen("ino %lu, pg %lu, pg flags %#lx",
@@ -1021,7 +1021,7 @@ static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
 
 	/* Is the page fully inside @i_size? */
 	if (page->index < end_index) {
-		if (page->index >= synced_i_size >> PAGE_CACHE_SHIFT) {
+		if (page->index >= synced_i_size >> PAGE_SHIFT) {
 			err = inode->i_sb->s_op->write_inode(inode, NULL);
 			if (err)
 				goto out_unlock;
@@ -1034,7 +1034,7 @@ static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
 			 * with this.
 			 */
 		}
-		return do_writepage(page, PAGE_CACHE_SIZE);
+		return do_writepage(page, PAGE_SIZE);
 	}
 
 	/*
@@ -1045,7 +1045,7 @@ static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
 	 * writes to that region are not written out to the file."
 	 */
 	kaddr = kmap_atomic(page);
-	memset(kaddr + len, 0, PAGE_CACHE_SIZE - len);
+	memset(kaddr + len, 0, PAGE_SIZE - len);
 	flush_dcache_page(page);
 	kunmap_atomic(kaddr);
 
@@ -1138,7 +1138,7 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
 	truncate_setsize(inode, new_size);
 
 	if (offset) {
-		pgoff_t index = new_size >> PAGE_CACHE_SHIFT;
+		pgoff_t index = new_size >> PAGE_SHIFT;
 		struct page *page;
 
 		page = find_lock_page(inode->i_mapping, index);
@@ -1157,9 +1157,9 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
 				clear_page_dirty_for_io(page);
 				if (UBIFS_BLOCKS_PER_PAGE_SHIFT)
 					offset = new_size &
-						 (PAGE_CACHE_SIZE - 1);
+						 (PAGE_SIZE - 1);
 				err = do_writepage(page, offset);
-				page_cache_release(page);
+				put_page(page);
 				if (err)
 					goto out_budg;
 				/*
@@ -1173,7 +1173,7 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode,
 				 * having to read it.
 				 */
 				unlock_page(page);
-				page_cache_release(page);
+				put_page(page);
 			}
 		}
 	}
@@ -1285,7 +1285,7 @@ static void ubifs_invalidatepage(struct page *page, unsigned int offset,
 	struct ubifs_info *c = inode->i_sb->s_fs_info;
 
 	ubifs_assert(PagePrivate(page));
-	if (offset || length < PAGE_CACHE_SIZE)
+	if (offset || length < PAGE_SIZE)
 		/* Partial page remains dirty */
 		return;
 
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index a233ba9..20daea9 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2240,9 +2240,9 @@ static int __init ubifs_init(void)
 	 * We require that PAGE_CACHE_SIZE is greater-than-or-equal-to
 	 * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
 	 */
-	if (PAGE_CACHE_SIZE < UBIFS_BLOCK_SIZE) {
+	if (PAGE_SIZE < UBIFS_BLOCK_SIZE) {
 		pr_err("UBIFS error (pid %d): VFS page cache size is %u bytes, but UBIFS requires at least 4096 bytes",
-		       current->pid, (unsigned int)PAGE_CACHE_SIZE);
+		       current->pid, (unsigned int)PAGE_SIZE);
 		return -EINVAL;
 	}
 
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index c2a57e1..4cd7e56 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -46,8 +46,8 @@
 #define UBIFS_SUPER_MAGIC 0x24051905
 
 /* Number of UBIFS blocks per VFS page */
-#define UBIFS_BLOCKS_PER_PAGE (PAGE_CACHE_SIZE / UBIFS_BLOCK_SIZE)
-#define UBIFS_BLOCKS_PER_PAGE_SHIFT (PAGE_CACHE_SHIFT - UBIFS_BLOCK_SHIFT)
+#define UBIFS_BLOCKS_PER_PAGE (PAGE_SIZE / UBIFS_BLOCK_SIZE)
+#define UBIFS_BLOCKS_PER_PAGE_SHIFT (PAGE_SHIFT - UBIFS_BLOCK_SHIFT)
 
 /* "File system end of life" sequence number watermark */
 #define SQNUM_WARN_WATERMARK 0xFFFFFFFF00000000ULL