xen/pvcalls: free active map buffer on pvcalls_front_free_map

Data buffer for active map is allocated in alloc_active_ring and freed
in free_active_ring function, which is used only for the error
cleanup. pvcalls_front_release is calling pvcalls_front_free_map which
ends foreign access for this buffer, but doesn't free allocated pages.
Call free_active_ring to clean all allocated resources.
Signed-off-by: Oleksii Moisieiev <oleksii_moisieiev@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/6a762ee32dd655cbb09a4aa0e2307e8919761311.1671531297.git.oleksii_moisieiev@epam.comSigned-off-by: Juergen Gross <jgross@suse.com>

drivers/xen/pvcalls-front.c

@@ -225,6 +225,8 @@ static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static void free_active_ring(struct sock_mapping *map);
+
 static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
 				   struct sock_mapping *map)
 {
@@ -240,7 +242,7 @@ static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
 	for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
 		gnttab_end_foreign_access(map->active.ring->ref[i], NULL);
 	gnttab_end_foreign_access(map->active.ref, NULL);
-	free_page((unsigned long)map->active.ring);
+	free_active_ring(map);
 
 	kfree(map);
 }