[XFS] Don't use kmap in xfs_iozero.
David Chinner [Sat, 10 Feb 2007 07:37:46 +0000 (18:37 +1100)]
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>

fs/xfs/linux-2.6/xfs_lrw.c

index 0b5c9b6..ff8d64e 100644 (file)
@@ -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)