[PATCH 29/40] Staging: hv: storvsc: Optimize bounce buffer handling for the "write" case
From: "K. Y. Srinivasan" <kys@microsoft.com>
Date: 2011-06-29 14:27:05
Also in:
lkml
Subsystem:
staging subsystem, the rest · Maintainers:
Greg Kroah-Hartman, Linus Torvalds
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@microsoft.com> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Abhishek Kane <redacted> Signed-off-by: Hank Janssen <redacted> --- 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