From: Johannes Thumshirn <jthumshirn@suse.de>
Date: Mon, 17 Jul 2017 13:11:42 +0000 (+0200)
Subject: scsi: sg: fix static checker warning in sg_is_valid_dxfer
X-Git-Tag: v3.16.85~22
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=99b6d6fb8a7e74d56d17808556995822b7ae8eed;p=thirdparty%2Fkernel%2Fstable.git

scsi: sg: fix static checker warning in sg_is_valid_dxfer

commit 14074aba4bcda3764c9a702b276308b89901d5b6 upstream.

dxfer_len is an unsigned int and we always assign a value > 0 to it, so
it doesn't make any sense to check if it is < 0. We can't really check
dxferp as well as we have both NULL and not NULL cases in the possible
call paths.

So just return true for SG_DXFER_FROM_DEV transfer in
sg_is_valid_dxfer().

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reported-by: Colin Ian King <colin.king@canonical.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 59c33205ade3d..88a41936c342a 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -796,8 +796,11 @@ static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
 			return false;
 		return true;
 	case SG_DXFER_FROM_DEV:
-		if (hp->dxfer_len < 0)
-			return false;
+		/*
+		 * for SG_DXFER_FROM_DEV we always set dxfer_len to > 0. dxferp
+		 * can either be NULL or != NULL so there's no point in checking
+		 * it either. So just return true.
+		 */
 		return true;
 	case SG_DXFER_TO_DEV:
 	case SG_DXFER_TO_FROM_DEV: