diff --git a/shm.c b/shm.c
index 6785cbfb..f58ca3e4 100644
--- a/shm.c
+++ b/shm.c
@@ -182,3 +182,20 @@ shm_fini(void)
         tll_remove(buffers, it);
     }
 }
+
+void
+shm_purge(struct wl_shm *shm, unsigned long cookie)
+{
+    LOG_DBG("cookie=%lx: purging all buffers", cookie);
+
+    /* Purge old buffers associated with this cookie */
+    tll_foreach(buffers, it) {
+        if (it->item.cookie != cookie)
+            continue;
+
+        assert(!it->item.busy);
+
+        buffer_destroy(&it->item);
+        tll_remove(buffers, it);
+    }
+}
diff --git a/shm.h b/shm.h
index 555c5d51..cec0ef81 100644
--- a/shm.h
+++ b/shm.h
@@ -24,3 +24,5 @@ struct buffer {
 struct buffer *shm_get_buffer(
     struct wl_shm *shm, int width, int height, unsigned long cookie);
 void shm_fini(void);
+
+void shm_purge(struct wl_shm *shm, unsigned long cookie);