Re: Nero 4 Linux applications broken in 4.12

[Johannes Thumshirn <jthumshirn@suse.de>]

On Wed, Jul 05, 2017 at 01:19:09PM +0100, Chris Clayton wrote:
> I'm happy to test any patches you may propose.

Can you verify this fix? Preferedably with using Nero. It passes my small
reproducer:

>From f52502180cc3843f8acc956253af2575245546a8 Mon Sep 17 00:00:00 2001
From: Johannes Thumshirn <jthumshirn@suse.de>
Date: Wed, 5 Jul 2017 14:31:47 +0200
Subject: [PATCH] scsi: sg: fix SG_DXFER_FROM_DEV transfers

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")
---
 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

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
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