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path: root/drivers/xen/grant-table.c
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Diffstat (limited to 'drivers/xen/grant-table.c')
-rw-r--r--drivers/xen/grant-table.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 04cdeb8e3719..c4d2298893b1 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -730,9 +730,18 @@ void gnttab_request_free_callback(struct gnttab_free_callback *callback,
void (*fn)(void *), void *arg, u16 count)
{
unsigned long flags;
+ struct gnttab_free_callback *cb;
+
spin_lock_irqsave(&gnttab_list_lock, flags);
- if (callback->next)
- goto out;
+
+ /* Check if the callback is already on the list */
+ cb = gnttab_free_callback_list;
+ while (cb) {
+ if (cb == callback)
+ goto out;
+ cb = cb->next;
+ }
+
callback->fn = fn;
callback->arg = arg;
callback->count = count;