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 9464f99bf7a1ed37b0d48adf33a42b74f0d63e58..90b91ade825a932edb0c8587721b206e25f8823d 100644 (file)
--- 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) {