[2,of,2] DM Snapshot: drop unneeded and

Commit Message

Jonthan Brassow Sept. 23, 2009, 2:58 p.m. UTC

Patch name: dm-snapshot-drop-unneeded-and.patch

Removed unneeded 'and' masking --- right shift discards the lower bits anyway,
so there is no need to clear them.

This is also needed for the correctness of the following patch
dm-snapshot-32bit-chunk-size.patch, that makes chunk_mask 32-bit.

Signed-off-by: Mikulas Patocka <[e-mail]>
Reviewed-by: Mike Snitzer <[e-mail]>
Reviewed-by: Jonathan Brassow <[e-mail]>


--
dm-devel mailing list
[e-mail]
https://www.redhat.com/mailman/listinfo/dm-devel

Patch

Index: linux-2.6/drivers/md/dm-exception-store.h
===================================================================
--- linux-2.6.orig/drivers/md/dm-exception-store.h
+++ linux-2.6/drivers/md/dm-exception-store.h
@@ -162,7 +162,7 @@  static inline sector_t get_dev_size(stru
 static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
 				      sector_t sector)
 {
-	return (sector & ~store->chunk_mask) >> store->chunk_shift;
+	return sector >> store->chunk_shift;
 }
 
 int dm_exception_store_type_register(struct dm_exception_store_type *type);