staging: hv: Fixed lockup problem with bounce_buffer scatter list

Fixed lockup problem with bounce_buffer scatter list which caused
crashes in heavy loads. And minor code indentation cleanup in effected
area.

Removed whitespace and noted minor indentation changes in description as
pointed out by Joe Perches. (Thanks for reviewing Joe)

Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index 3b9ccb062008..62882a437aa4 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -615,6 +615,7 @@ static int storvsc_queuecommand(struct scsi_cmnd *scmnd,
         unsigned int request_size = 0;
         int i;
         struct scatterlist *sgl;
+        unsigned int sg_count = 0;
 
         DPRINT_DBG(STORVSC_DRV, "scmnd %p dir %d, use_sg %d buf %p len %d "
                    "queue depth %d tagged %d", scmnd, scmnd->sc_data_direction,
@@ -697,6 +698,7 @@ static int storvsc_queuecommand(struct scsi_cmnd *scmnd,
         request->DataBuffer.Length = scsi_bufflen(scmnd);
         if (scsi_sg_count(scmnd)) {
                 sgl = (struct scatterlist *)scsi_sglist(scmnd);
+                sg_count = scsi_sg_count(scmnd);
 
                 /* check if we need to bounce the sgl */
                 if (do_bounce_buffer(sgl, scsi_sg_count(scmnd)) != -1) {
@@ -731,15 +733,16 @@ static int storvsc_queuecommand(struct scsi_cmnd *scmnd,
                                               scsi_sg_count(scmnd));
 
                         sgl = cmd_request->bounce_sgl;
+                        sg_count = cmd_request->bounce_sgl_count;
                 }
 
                 request->DataBuffer.Offset = sgl[0].offset;
 
-                for (i = 0; i < scsi_sg_count(scmnd); i++) {
+                for (i = 0; i < sg_count; i++) {
                         DPRINT_DBG(STORVSC_DRV, "sgl[%d] len %d offset %d\n",
                                    i, sgl[i].length, sgl[i].offset);
                         request->DataBuffer.PfnArray[i] =
-                                        page_to_pfn(sg_page((&sgl[i])));
+                                page_to_pfn(sg_page((&sgl[i])));
                 }
         } else if (scsi_sglist(scmnd)) {
                 /* ASSERT(scsi_bufflen(scmnd) <= PAGE_SIZE); */