[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>

drivers/scsi/scsi.c

@@ -169,12 +169,10 @@ scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
 {
 	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) {