From mboxrd@z Thu Jan 1 00:00:00 1970 From: "K. Y. Srinivasan" Subject: [PATCH 29/40] Staging: hv: storvsc: Optimize bounce buffer handling for the "write" case Date: Wed, 29 Jun 2011 07:39:26 -0700 Message-ID: <1309358377-8537-29-git-send-email-kys@microsoft.com> References: <1309358301-8488-1-git-send-email-kys@microsoft.com> <1309358377-8537-1-git-send-email-kys@microsoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1309358377-8537-1-git-send-email-kys@microsoft.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: devel-bounces@linuxdriverproject.org Errors-To: devel-bounces@linuxdriverproject.org To: gregkh@suse.de, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, virtualization@lists.osdl.org Cc: Haiyang Zhang , Abhishek Kane List-Id: virtualization@lists.linuxfoundation.org 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 Signed-off-by: Haiyang Zhang Signed-off-by: Abhishek Kane Signed-off-by: Hank Janssen --- 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