xen/pvcalls: fix unsigned less than zero error check

The check on bedata->ref is never true because ref is an unsigned
integer. Fix this by assigning signed int ret to the return of the
call to gnttab_claim_grant_reference so the -ve return can be checked.

Detected by CoverityScan, CID#1460358 ("Unsigned compared against 0")

Fixes: 2196819099 ("xen/pvcalls: connect to the backend")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Colin Ian King 2017-11-03 08:42:02 +00:00 committed by Boris Ostrovsky
parent b5494ad83f
commit 95110ac88d

View file

@ -1186,11 +1186,10 @@ static int pvcalls_front_probe(struct xenbus_device *dev,
ret = gnttab_alloc_grant_references(1, &gref_head);
if (ret < 0)
goto error;
bedata->ref = gnttab_claim_grant_reference(&gref_head);
if (bedata->ref < 0) {
ret = bedata->ref;
ret = gnttab_claim_grant_reference(&gref_head);
if (ret < 0)
goto error;
}
bedata->ref = ret;
gnttab_grant_foreign_access_ref(bedata->ref, dev->otherend_id,
virt_to_gfn((void *)sring), 0);