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, 15 insertions, 15 deletions

diff --git a/fs/dax.c b/fs/dax.c
index 90322eb..1f95416 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -323,7 +323,7 @@ static int dax_load_hole(struct address_space *mapping, struct page *page,
 	size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	if (vmf->pgoff >= size) {
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		return VM_FAULT_SIGBUS;
 	}
 
@@ -351,7 +351,7 @@ static int copy_user_bh(struct page *to, struct inode *inode,
 }
 
 #define NO_SECTOR -1
-#define DAX_PMD_INDEX(page_index) (page_index & (PMD_MASK >> PAGE_CACHE_SHIFT))
+#define DAX_PMD_INDEX(page_index) (page_index & (PMD_MASK >> PAGE_SHIFT))
 
 static int dax_radix_entry(struct address_space *mapping, pgoff_t index,
 		sector_t sector, bool pmd_entry, bool dirty)
@@ -506,8 +506,8 @@ int dax_writeback_mapping_range(struct address_space *mapping,
 	if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL)
 		return 0;
 
-	start_index = wbc->range_start >> PAGE_CACHE_SHIFT;
-	end_index = wbc->range_end >> PAGE_CACHE_SHIFT;
+	start_index = wbc->range_start >> PAGE_SHIFT;
+	end_index = wbc->range_end >> PAGE_SHIFT;
 	pmd_index = DAX_PMD_INDEX(start_index);
 
 	rcu_read_lock();
@@ -642,12 +642,12 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 	page = find_get_page(mapping, vmf->pgoff);
 	if (page) {
 		if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) {
-			page_cache_release(page);
+			put_page(page);
 			return VM_FAULT_RETRY;
 		}
 		if (unlikely(page->mapping != mapping)) {
 			unlock_page(page);
-			page_cache_release(page);
+			put_page(page);
 			goto repeat;
 		}
 		size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -711,10 +711,10 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 
 	if (page) {
 		unmap_mapping_range(mapping, vmf->pgoff << PAGE_SHIFT,
-							PAGE_CACHE_SIZE, 0);
+							PAGE_SIZE, 0);
 		delete_from_page_cache(page);
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 		page = NULL;
 	}
 
@@ -747,7 +747,7 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
  unlock_page:
 	if (page) {
 		unlock_page(page);
-		page_cache_release(page);
+		put_page(page);
 	}
 	goto out;
 }
@@ -1104,18 +1104,18 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length,
 							get_block_t get_block)
 {
 	struct buffer_head bh;
-	pgoff_t index = from >> PAGE_CACHE_SHIFT;
-	unsigned offset = from & (PAGE_CACHE_SIZE-1);
+	pgoff_t index = from >> PAGE_SHIFT;
+	unsigned offset = from & (PAGE_SIZE-1);
 	int err;
 
 	/* Block boundary? Nothing to do */
 	if (!length)
 		return 0;
-	BUG_ON((offset + length) > PAGE_CACHE_SIZE);
+	BUG_ON((offset + length) > PAGE_SIZE);
 
 	memset(&bh, 0, sizeof(bh));
 	bh.b_bdev = inode->i_sb->s_bdev;
-	bh.b_size = PAGE_CACHE_SIZE;
+	bh.b_size = PAGE_SIZE;
 	err = get_block(inode, index, &bh, 0);
 	if (err < 0)
 		return err;
@@ -1123,7 +1123,7 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length,
 		struct block_device *bdev = bh.b_bdev;
 		struct blk_dax_ctl dax = {
 			.sector = to_sector(&bh, inode),
-			.size = PAGE_CACHE_SIZE,
+			.size = PAGE_SIZE,
 		};
 
 		if (dax_map_atomic(bdev, &dax) < 0)
@@ -1154,7 +1154,7 @@ EXPORT_SYMBOL_GPL(dax_zero_page_range);
  */
 int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block)
 {
-	unsigned length = PAGE_CACHE_ALIGN(from) - from;
+	unsigned length = PAGE_ALIGN(from) - from;
 	return dax_zero_page_range(inode, from, length, get_block);
 }
 EXPORT_SYMBOL_GPL(dax_truncate_page);