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, 12 insertions, 11 deletions

diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c
index cad86bac3453..0e62dec3effc 100644
--- a/fs/jffs2/file.c
+++ b/fs/jffs2/file.c
@@ -87,14 +87,15 @@ static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
         int ret;
 
         jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
-                  __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT);
+                  __func__, inode->i_ino, pg->index << PAGE_SHIFT);
 
         BUG_ON(!PageLocked(pg));
 
         pg_buf = kmap(pg);
         /* FIXME: Can kmap fail? */
 
-        ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE);
+        ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT,
+                                     PAGE_SIZE);
 
         if (ret) {
                 ClearPageUptodate(pg);
@@ -137,8 +138,8 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
         struct page *pg;
         struct inode *inode = mapping->host;
         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
-        pgoff_t index = pos >> PAGE_CACHE_SHIFT;
-        uint32_t pageofs = index << PAGE_CACHE_SHIFT;
+        pgoff_t index = pos >> PAGE_SHIFT;
+        uint32_t pageofs = index << PAGE_SHIFT;
         int ret = 0;
 
         pg = grab_cache_page_write_begin(mapping, index, flags);
@@ -230,7 +231,7 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 
 out_page:
         unlock_page(pg);
-        page_cache_release(pg);
+        put_page(pg);
         return ret;
 }
 
@@ -245,14 +246,14 @@ static int jffs2_write_end(struct file *filp, struct address_space *mapping,
         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
         struct jffs2_raw_inode *ri;
-        unsigned start = pos & (PAGE_CACHE_SIZE - 1);
+        unsigned start = pos & (PAGE_SIZE - 1);
         unsigned end = start + copied;
         unsigned aligned_start = start & ~3;
         int ret = 0;
         uint32_t writtenlen = 0;
 
         jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
-                  __func__, inode->i_ino, pg->index << PAGE_CACHE_SHIFT,
+                  __func__, inode->i_ino, pg->index << PAGE_SHIFT,
                   start, end, pg->flags);
 
         /* We need to avoid deadlock with page_cache_read() in
@@ -261,7 +262,7 @@ static int jffs2_write_end(struct file *filp, struct address_space *mapping,
            to re-lock it. */
         BUG_ON(!PageUptodate(pg));
 
-        if (end == PAGE_CACHE_SIZE) {
+        if (end == PAGE_SIZE) {
                 /* When writing out the end of a page, write out the
                    _whole_ page. This helps to reduce the number of
                    nodes in files which have many short writes, like
@@ -275,7 +276,7 @@ static int jffs2_write_end(struct file *filp, struct address_space *mapping,
                 jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
                           __func__);
                 unlock_page(pg);
-                page_cache_release(pg);
+                put_page(pg);
                 return -ENOMEM;
         }
 
@@ -292,7 +293,7 @@ static int jffs2_write_end(struct file *filp, struct address_space *mapping,
         kmap(pg);
 
         ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
-                                      (pg->index << PAGE_CACHE_SHIFT) + aligned_start,
+                                      (pg->index << PAGE_SHIFT) + aligned_start,
                                       end - aligned_start, &writtenlen);
 
         kunmap(pg);
@@ -329,6 +330,6 @@ static int jffs2_write_end(struct file *filp, struct address_space *mapping,
         jffs2_dbg(1, "%s() returning %d\n",
                   __func__, writtenlen > 0 ? writtenlen : ret);
         unlock_page(pg);
-        page_cache_release(pg);
+        put_page(pg);
         return writtenlen > 0 ? writtenlen : ret;
 }