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, 16 insertions, 16 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 9947b5c69664..b018eb485019 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -88,7 +88,7 @@ out_unlock:
 static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
                                         struct pipe_buffer *buf)
 {
-        page_cache_release(buf->page);
+        put_page(buf->page);
         buf->flags &= ~PIPE_BUF_FLAG_LRU;
 }
 
@@ -268,7 +268,7 @@ EXPORT_SYMBOL_GPL(splice_to_pipe);
 
 void spd_release_page(struct splice_pipe_desc *spd, unsigned int i)
 {
-        page_cache_release(spd->pages[i]);
+        put_page(spd->pages[i]);
 }
 
 /*
@@ -328,9 +328,9 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
         if (splice_grow_spd(pipe, &spd))
                 return -ENOMEM;
 
-        index = *ppos >> PAGE_CACHE_SHIFT;
-        loff = *ppos & ~PAGE_CACHE_MASK;
-        req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+        index = *ppos >> PAGE_SHIFT;
+        loff = *ppos & ~PAGE_MASK;
+        req_pages = (len + loff + PAGE_SIZE - 1) >> PAGE_SHIFT;
         nr_pages = min(req_pages, spd.nr_pages_max);
 
         /*
@@ -365,7 +365,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                         error = add_to_page_cache_lru(page, mapping, index,
                                    mapping_gfp_constraint(mapping, GFP_KERNEL));
                         if (unlikely(error)) {
-                                page_cache_release(page);
+                                put_page(page);
                                 if (error == -EEXIST)
                                         continue;
                                 break;
@@ -385,7 +385,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
          * Now loop over the map and see if we need to start IO on any
          * pages, fill in the partial map, etc.
          */
-        index = *ppos >> PAGE_CACHE_SHIFT;
+        index = *ppos >> PAGE_SHIFT;
         nr_pages = spd.nr_pages;
         spd.nr_pages = 0;
         for (page_nr = 0; page_nr < nr_pages; page_nr++) {
@@ -397,7 +397,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                 /*
                  * this_len is the max we'll use from this page
                  */
-                this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
+                this_len = min_t(unsigned long, len, PAGE_SIZE - loff);
                 page = spd.pages[page_nr];
 
                 if (PageReadahead(page))
@@ -426,7 +426,7 @@ retry_lookup:
                                         error = -ENOMEM;
                                         break;
                                 }
-                                page_cache_release(spd.pages[page_nr]);
+                                put_page(spd.pages[page_nr]);
                                 spd.pages[page_nr] = page;
                         }
                         /*
@@ -456,7 +456,7 @@ fill_it:
                  * i_size must be checked after PageUptodate.
                  */
                 isize = i_size_read(mapping->host);
-                end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
+                end_index = (isize - 1) >> PAGE_SHIFT;
                 if (unlikely(!isize || index > end_index))
                         break;
 
@@ -470,7 +470,7 @@ fill_it:
                         /*
                          * max good bytes in this page
                          */
-                        plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
+                        plen = ((isize - 1) & ~PAGE_MASK) + 1;
                         if (plen <= loff)
                                 break;
 
@@ -494,8 +494,8 @@ fill_it:
          * we got, 'nr_pages' is how many pages are in the map.
          */
         while (page_nr < nr_pages)
-                page_cache_release(spd.pages[page_nr++]);
-        in->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
+                put_page(spd.pages[page_nr++]);
+        in->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
 
         if (spd.nr_pages)
                 error = splice_to_pipe(pipe, &spd);
@@ -636,8 +636,8 @@ ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
                         goto shrink_ret;
         }
 
-        offset = *ppos & ~PAGE_CACHE_MASK;
-        nr_pages = (len + offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+        offset = *ppos & ~PAGE_MASK;
+        nr_pages = (len + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 
         for (i = 0; i < nr_pages && i < spd.nr_pages_max && len; i++) {
                 struct page *page;
@@ -647,7 +647,7 @@ ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
                 if (!page)
                         goto err;
 
-                this_len = min_t(size_t, len, PAGE_CACHE_SIZE - offset);
+                this_len = min_t(size_t, len, PAGE_SIZE - offset);
                 vec[i].iov_base = (void __user *) page_address(page);
                 vec[i].iov_len = this_len;
                 spd.pages[i] = page;