Btrfs: kmap_atomic(KM_USER0) is safe for btrfs_readpage_end_io_hook
None of the checksum verification code schedules, so we can use the faster
kmap_atomic
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index cdb7011..8adfe05 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1748,7 +1748,7 @@
} else {
ret = get_state_private(io_tree, start, &private);
}
- kaddr = kmap(page);
+ kaddr = kmap_atomic(page, KM_USER0);
if (ret)
goto zeroit;
@@ -1757,7 +1757,7 @@
if (csum != private)
goto zeroit;
- kunmap(page);
+ kunmap_atomic(kaddr, KM_USER0);
good:
/* if the io failure tree for this inode is non-empty,
* check to see if we've recovered from a failed IO
@@ -1772,7 +1772,7 @@
(unsigned long long)private);
memset(kaddr + offset, 1, end - start + 1);
flush_dcache_page(page);
- kunmap(page);
+ kunmap_atomic(kaddr, KM_USER0);
if (private == 0)
return 0;
return -EIO;
