[XFS] Don't use kmap in xfs_iozero.

kmap() is inefficient and does not scale well. kmap_atomic() is a better
choice. Use the generic wrapper function instead of open coding the
kmap-memset-dcache flush-kunmap stuff.

SGI-PV: 960904
SGI-Modid: xfs-linux-melb:xfs-kern:28041a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/fs/xfs/linux-2.6/xfs_lrw.c b/fs/xfs/linux-2.6/xfs_lrw.c
index 0b5c9b6774c8..ff8d64eba9f8 100644
--- a/fs/xfs/linux-2.6/xfs_lrw.c
+++ b/fs/xfs/linux-2.6/xfs_lrw.c
@@ -137,7 +137,6 @@ xfs_iozero(
         unsigned                bytes;
         struct page             *page;
         struct address_space    *mapping;
-        char                    *kaddr;
         int                     status;
 
         mapping = ip->i_mapping;
@@ -155,15 +154,13 @@ xfs_iozero(
                 if (!page)
                         break;
 
-                kaddr = kmap(page);
                 status = mapping->a_ops->prepare_write(NULL, page, offset,
                                                         offset + bytes);
-                if (status) {
+                if (status)
                         goto unlock;
-                }
 
-                memset((void *) (kaddr + offset), 0, bytes);
-                flush_dcache_page(page);
+                memclear_highpage_flush(page, offset, bytes);
+
                 status = mapping->a_ops->commit_write(NULL, page, offset,
                                                         offset + bytes);
                 if (!status) {
@@ -172,7 +169,6 @@ xfs_iozero(
                 }
 
 unlock:
-                kunmap(page);
                 unlock_page(page);
                 page_cache_release(page);
                 if (status)