[PATCH 30/40] Staging: hv: storvsc: Optimize the bounce buffer handling in the "read" case
From: K. Y. Srinivasan
Date: Wed Jun 29 2011 - 10:28:22 EST
Optimize the bounce buffer handling in the "read" case. Copy to bounce
buffers (if needed) when we initiate an I/O, only if we are
performing a "write" operation.
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Signed-off-by: Abhishek Kane <v-abkane@xxxxxxxxxxxxx>
Signed-off-by: Hank Janssen <hjanssen@xxxxxxxxxxxxx>
---
drivers/staging/hv/storvsc_drv.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index c6838fd..23334ad 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -623,12 +623,10 @@ static int storvsc_queuecommand_lck(struct scsi_cmnd *scmnd,
ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
PAGE_SHIFT;
- /*
- * FIXME: We can optimize on reads by just skipping
- * this
- */
- copy_to_bounce_buffer(sgl, cmd_request->bounce_sgl,
- scsi_sg_count(scmnd));
+ if (vm_srb->data_in == WRITE_TYPE)
+ copy_to_bounce_buffer(sgl,
+ cmd_request->bounce_sgl,
+ scsi_sg_count(scmnd));
sgl = cmd_request->bounce_sgl;
sg_count = cmd_request->bounce_sgl_count;
--
1.7.4.1
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