xen-gntalloc: signedness bug in add_grefs()

PATCH In review Dan Carpenter 1 participant 1 message Nov 4, 2011

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Kernel janitors Xen hypervisor interface

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Dan Carpenter

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2011-11-04 18:24 UTC #0 lore raw

PATCH 2/2 xen-gntalloc: signedness bug in add_grefs()

gref->gref_id is unsigned so the error handling didn't work. gnttab_grant_foreign_access() returns an int type, so we can add a cast here, and it doesn't cause any problems. gnttab_grant_foreign_access() can return a variety of errors including -ENOSPC, -ENOSYS and -ENOMEM.

Signed-off-by Dan Carpenter <[email protected]>

drivers/xen/gntalloc.c +1 -1

index 23c60cf..e1c4c6e 100644
@@ -135,7 +135,7 @@ static int add_grefs(struct ioctl_gntalloc_alloc_gref *op,
 		/* Grant foreign access to the page. */
 		gref->gref_id = gnttab_grant_foreign_access(op->domid,
 			pfn_to_mfn(page_to_pfn(gref->page)), readonly);
-		if (gref->gref_id < 0) {
+		if ((int)gref->gref_id < 0) {
 			rc = gref->gref_id;
 			goto undo;
 		}