[PATCH 099/117] Staging: hv: storvsc: Optimize bounce buffer handling for the "write" case

K. Y. Srinivasan
Fri, 15 Jul 2011 17:47:27 -0000

Optimize bounce buffer handling for the "write" case.

Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz at microsoft.com>
---
 drivers/staging/hv/storvsc_drv.c |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index 5777482..e2294d5 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -428,17 +428,17 @@ 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) {
--
1.7.4.1