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>

2 files changed, 6 insertions, 6 deletions

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index e2c0057737e6..7c887f111a7d 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -75,7 +75,7 @@ static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
 				break;
 			}
 
-		page_cache_release(page);
+		put_page(page);
 		pages--;
 		index++;
 	}
@@ -124,7 +124,7 @@ static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
 			return PTR_ERR(page);
 
 		memcpy(buf, page_address(page) + offset, cpylen);
-		page_cache_release(page);
+		put_page(page);
 
 		if (retlen)
 			*retlen += cpylen;
@@ -164,7 +164,7 @@ static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf,
 			unlock_page(page);
 			balance_dirty_pages_ratelimited(mapping);
 		}
-		page_cache_release(page);
+		put_page(page);
 
 		if (retlen)
 			*retlen += cpylen;
diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index 1fd519503bb1..a58169a28741 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -1339,7 +1339,7 @@ static void put_pages(struct nandsim *ns)
 	int i;
 
 	for (i = 0; i < ns->held_cnt; i++)
-		page_cache_release(ns->held_pages[i]);
+		put_page(ns->held_pages[i]);
 }
 
 /* Get page cache pages in advance to provide NOFS memory allocation */
@@ -1349,8 +1349,8 @@ static int get_pages(struct nandsim *ns, struct file *file, size_t count, loff_t
 	struct page *page;
 	struct address_space *mapping = file->f_mapping;
 
-	start_index = pos >> PAGE_CACHE_SHIFT;
-	end_index = (pos + count - 1) >> PAGE_CACHE_SHIFT;
+	start_index = pos >> PAGE_SHIFT;
+	end_index = (pos + count - 1) >> PAGE_SHIFT;
 	if (end_index - start_index + 1 > NS_MAX_HELD_PAGES)
 		return -EINVAL;
 	ns->held_cnt = 0;