linux-kernel - [PATCH 29/40] Staging: hv: storvsc: Optimize bounce buffer handling for the "write" case

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1309358377-8537-29-git-send-email-kys@microsoft.com>
Date:	Wed, 29 Jun 2011 07:39:26 -0700
From:	"K. Y. Srinivasan" <kys@...rosoft.com>
To:	gregkh@...e.de, linux-kernel@...r.kernel.org,
	devel@...uxdriverproject.org, virtualization@...ts.osdl.org
Cc:	"K. Y. Srinivasan" <kys@...rosoft.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	Abhishek Kane <v-abkane@...rosoft.com>,
	Hank Janssen <hjanssen@...rosoft.com>
Subject: [PATCH 29/40] Staging: hv: storvsc: Optimize bounce buffer handling for the "write" case

Optimize bounce buffer handling for the "write" case; we need to copy
from bounce buffer only when we are performing a "read" operation.

Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@...rosoft.com>
Signed-off-by: Abhishek Kane <v-abkane@...rosoft.com>
Signed-off-by: Hank Janssen <hjanssen@...rosoft.com>
---
 drivers/staging/hv/storvsc_drv.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index fc53bf6..c6838fd 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -478,17 +478,18 @@ static void storvsc_commmand_completion(struct hv_storvsc_request *request)
 	struct scsi_sense_hdr sense_hdr;
 	struct vmscsi_request *vm_srb;
 
+	vm_srb = &request->vstor_packet.vm_srb;
 	if (cmd_request->bounce_sgl_count) {
 
-		/* FIXME: We can optimize on writes by just skipping this */
-		copy_from_bounce_buffer(scsi_sglist(scmnd),
+		if (vm_srb->data_in == READ_TYPE) {
+			copy_from_bounce_buffer(scsi_sglist(scmnd),
 					cmd_request->bounce_sgl,
 					scsi_sg_count(scmnd));
-		destroy_bounce_buffer(cmd_request->bounce_sgl,
-				      cmd_request->bounce_sgl_count);
+			destroy_bounce_buffer(cmd_request->bounce_sgl,
+					cmd_request->bounce_sgl_count);
+		}
 	}
 
-	vm_srb = &request->vstor_packet.vm_srb;
 	scmnd->result = vm_srb->scsi_status;
 
 	if (scmnd->result) {
-- 
1.7.4.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/