dax: guarantee page aligned results from bdev_direct_access()

If a ->direct_access() implementation ever returns a map count less than
PAGE_SIZE, catch the error in bdev_direct_access().  This simplifies
error checking in upper layers.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/fs/dax.c b/fs/dax.c
index 11721c0fc127..1080fb50fa4d 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -52,7 +52,6 @@ int dax_clear_blocks(struct inode *inode, sector_t block, long size)
 		sz = min_t(long, count, SZ_128K);
 		clear_pmem(addr, sz);
 		size -= sz;
-		BUG_ON(sz & 511);
 		sector += sz / 512;
 		cond_resched();
 	} while (size);