mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage

Mostly direct substitution with occasional adjustment or removing
outdated comments.

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>
diff --git a/fs/squashfs/cache.c b/fs/squashfs/cache.c
index 27e501a..23813c0 100644
--- a/fs/squashfs/cache.c
+++ b/fs/squashfs/cache.c
@@ -30,7 +30,7 @@
  * access the metadata and fragment caches.
  *
  * To avoid out of memory and fragmentation issues with vmalloc the cache
- * uses sequences of kmalloced PAGE_CACHE_SIZE buffers.
+ * uses sequences of kmalloced PAGE_SIZE buffers.
  *
  * It should be noted that the cache is not used for file datablocks, these
  * are decompressed and cached in the page-cache in the normal way.  The
@@ -231,7 +231,7 @@
 /*
  * Initialise cache allocating the specified number of entries, each of
  * size block_size.  To avoid vmalloc fragmentation issues each entry
- * is allocated as a sequence of kmalloced PAGE_CACHE_SIZE buffers.
+ * is allocated as a sequence of kmalloced PAGE_SIZE buffers.
  */
 struct squashfs_cache *squashfs_cache_init(char *name, int entries,
 	int block_size)