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, 7 insertions, 7 deletions

diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 09fe622274e4..158a3a39f82d 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -74,7 +74,7 @@ int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
         loff_t offset;
         int rc;
 
-        offset = ((((loff_t)page_for_lower->index) << PAGE_CACHE_SHIFT)
+        offset = ((((loff_t)page_for_lower->index) << PAGE_SHIFT)
                   + offset_in_page);
         virt = kmap(page_for_lower);
         rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size);
@@ -123,9 +123,9 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
         else
                 pos = offset;
         while (pos < (offset + size)) {
-                pgoff_t ecryptfs_page_idx = (pos >> PAGE_CACHE_SHIFT);
-                size_t start_offset_in_page = (pos & ~PAGE_CACHE_MASK);
-                size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page);
+                pgoff_t ecryptfs_page_idx = (pos >> PAGE_SHIFT);
+                size_t start_offset_in_page = (pos & ~PAGE_MASK);
+                size_t num_bytes = (PAGE_SIZE - start_offset_in_page);
                 loff_t total_remaining_bytes = ((offset + size) - pos);
 
                 if (fatal_signal_pending(current)) {
@@ -165,7 +165,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
                          * Fill in zero values to the end of the page */
                         memset(((char *)ecryptfs_page_virt
                                 + start_offset_in_page), 0,
-                                PAGE_CACHE_SIZE - start_offset_in_page);
+                                PAGE_SIZE - start_offset_in_page);
                 }
 
                 /* pos >= offset, we are now writing the data request */
@@ -186,7 +186,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
                                                 ecryptfs_page,
                                                 start_offset_in_page,
                                                 data_offset);
-                page_cache_release(ecryptfs_page);
+                put_page(ecryptfs_page);
                 if (rc) {
                         printk(KERN_ERR "%s: Error encrypting "
                                "page; rc = [%d]\n", __func__, rc);
@@ -262,7 +262,7 @@ int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
         loff_t offset;
         int rc;
 
-        offset = ((((loff_t)page_index) << PAGE_CACHE_SHIFT) + offset_in_page);
+        offset = ((((loff_t)page_index) << PAGE_SHIFT) + offset_in_page);
         virt = kmap(page_for_ecryptfs);
         rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode);
         if (rc > 0)