From: Chen, Kenneth W <kenneth.w.chen@intel.com>
Date: Wed, 13 Jul 2005 00:06:14 +0000 (-0700)
Subject: [SCSI] Redundant memset in scsi_alloc_sgtable
X-Git-Tag: v2.6.13-rc4~75^2~2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0f34e3f53378a11c9ecba0f8165da50e8b01d53f;p=linux-2.6

[SCSI] Redundant memset in scsi_alloc_sgtable

scsi_init_io calls scsi_alloc_sgtable and then calls blk_rq_map_sg
to initialize the scatterlist structure.  blk_rq_map_sg() already
memset the structure for every new segment.  That makes the memset
in scsi_alloc_sgtable unnecessary.

Patch to delete the extra memset in scsi_alloc_sgtable.  Tested on
a x86_64 machine.  Looks stable to me.

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
---

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 58dcb0534a..cab535809d 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -614,8 +614,6 @@ static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, int gfp_mas
 
 	sgp = scsi_sg_pools + cmd->sglist_len;
 	sgl = mempool_alloc(sgp->pool, gfp_mask);
-	if (sgl)
-		memset(sgl, 0, sgp->size);
 	return sgl;
 }