[SCSI] use kmem_cache_zalloc instead of kmem_cache_alloc/memset

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index a2ef032..166417a 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -169,12 +169,10 @@
 {
 	struct scsi_cmnd *cmd;
 
-	cmd = kmem_cache_alloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
+	cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
 	if (!cmd)
 		return NULL;
 
-	memset(cmd, 0, sizeof(*cmd));
-
 	cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
 					     gfp_mask | pool->gfp_mask);
 	if (!cmd->sense_buffer) {