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, 8 insertions, 8 deletions

diff --git a/fs/qnx6/dir.c b/fs/qnx6/dir.c
index e1f37278cf97..144ceda4948e 100644
--- a/fs/qnx6/dir.c
+++ b/fs/qnx6/dir.c
@@ -35,9 +35,9 @@ static struct page *qnx6_get_page(struct inode *dir, unsigned long n)
 static unsigned last_entry(struct inode *inode, unsigned long page_nr)
 {
         unsigned long last_byte = inode->i_size;
-        last_byte -= page_nr << PAGE_CACHE_SHIFT;
-        if (last_byte > PAGE_CACHE_SIZE)
-                last_byte = PAGE_CACHE_SIZE;
+        last_byte -= page_nr << PAGE_SHIFT;
+        if (last_byte > PAGE_SIZE)
+                last_byte = PAGE_SIZE;
         return last_byte / QNX6_DIR_ENTRY_SIZE;
 }
 
@@ -47,9 +47,9 @@ static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
 {
         struct qnx6_sb_info *sbi = QNX6_SB(sb);
         u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
-        u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */
+        u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */
         /* within page */
-        u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK;
+        u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_MASK;
         struct address_space *mapping = sbi->longfile->i_mapping;
         struct page *page = read_mapping_page(mapping, n, NULL);
         if (IS_ERR(page))
@@ -115,8 +115,8 @@ static int qnx6_readdir(struct file *file, struct dir_context *ctx)
         struct qnx6_sb_info *sbi = QNX6_SB(s);
         loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1);
         unsigned long npages = dir_pages(inode);
-        unsigned long n = pos >> PAGE_CACHE_SHIFT;
-        unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE;
+        unsigned long n = pos >> PAGE_SHIFT;
+        unsigned start = (pos & ~PAGE_MASK) / QNX6_DIR_ENTRY_SIZE;
         bool done = false;
 
         ctx->pos = pos;
@@ -131,7 +131,7 @@ static int qnx6_readdir(struct file *file, struct dir_context *ctx)
 
                 if (IS_ERR(page)) {
                         pr_err("%s(): read failed\n", __func__);
-                        ctx->pos = (n + 1) << PAGE_CACHE_SHIFT;
+                        ctx->pos = (n + 1) << PAGE_SHIFT;
                         return PTR_ERR(page);
                 }
                 de = ((struct qnx6_dir_entry *)page_address(page)) + start;