From: K. Y. Srinivasan <kys@microsoft.com>
Date: Sat, 27 Aug 2011 18:31:20 +0000 (-0700)
Subject: Staging: hv: storvsc: Optimize bounce buffer handling for the "write" case
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=3612ef99b05f107d5cd85f6bc45b94ed880d78f3;p=deliverable%2Flinux.git

Staging: hv: storvsc: Optimize bounce buffer handling for the "write" case

Optimize bounce buffer handling for the "write" case.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index 9464f99bf7a1..90b91ade825a 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -425,17 +425,17 @@ 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) {