[Xen-devel] [PATCH] xen/pvcalls: fix unsigned less than zero error check

[Colin King <colin.king@xxxxxxxxxxxxx>]

From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

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: 219681909913 ("xen/pvcalls: connect to the backend")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
 drivers/xen/pvcalls-front.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 0c1ec6894cc4..de8a470351a5 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -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);
 
-- 
2.14.1


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