[PATCH] scsi: sg: fix SG_DXFER_FROM_DEV transfers

Johannes Thumshirn
2017-07-05T13:49:53Z

SG_DXFER_FROM_DEV transfers do not have a dxferp as we set it to NULL,
but must have a length bigger than 0. This fixes a regression introduced
by commit 28676d869bbb ("scsi: sg: check for valid direction before
starting the request")

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Fixes: 28676d869bbb ("scsi: sg: check for valid direction before starting the request")
Reported-by: Chris Clayton <chris2553@googlemail.com>
Tested-by: Chris Clayton <chris2553@googlemail.com>
Cc: Doug Gilbert <dgilbert@interlog.com>
---
drivers/scsi/sg.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 21225d62b0c1..3c91593260aa 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -758,8 +758,11 @@ static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
if (hp->dxferp || hp->dxfer_len > 0)
return false;
return true;
- case SG_DXFER_TO_DEV:
case SG_DXFER_FROM_DEV:
+ if (hp->dxferp || hp->dxfer_len < 0)
+ return false;
+ return true;
+ case SG_DXFER_TO_DEV:
case SG_DXFER_TO_FROM_DEV:
if (!hp->dxferp || hp->dxfer_len == 0)
return false;
--
2.12.3