Make sure a reserved grant is never put on the free list, as this could
cause hard to debug errors.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
static void put_free_entry(grant_ref_t ref)
{
unsigned long flags;
+
+ if (unlikely(ref < GNTTAB_NR_RESERVED_ENTRIES))
+ return;
+
spin_lock_irqsave(&gnttab_list_lock, flags);
gnttab_entry(ref) = gnttab_free_head;
gnttab_free_head = ref;