LU-10428 lnet: call event handlers without res_lock

[fs/lustre-release.git] / lnet / include / lnet / lib-lnet.h

diff --git a/lnet/include/lnet/lib-lnet.h b/lnet/include/lnet/lib-lnet.h
index 6bfe88d..a7de9a4 100644 (file)
--- a/lnet/include/lnet/lib-lnet.h
+++ b/lnet/include/lnet/lib-lnet.h
@@ -244,6 +244,33 @@ lnet_ni_set_status(struct lnet_ni *ni, __u32 status)
        return update;
 }
 
+static inline void lnet_md_wait_handling(struct lnet_libmd *md, int cpt)
+{
+       wait_queue_head_t *wq = __var_waitqueue(md);
+#ifdef HAVE_WAIT_QUEUE_ENTRY
+       struct wait_bit_queue_entry entry;
+       wait_queue_entry_t *wqe = &entry.wq_entry;
+#else
+       struct wait_bit_queue entry;
+       wait_queue_entry_t *wqe = &entry.wait;
+#endif
+       init_wait_var_entry(&entry, md, 0);
+       prepare_to_wait_event(wq, wqe, TASK_IDLE);
+       if (md->md_flags & LNET_MD_FLAG_HANDLING) {
+               /* Race with unlocked call to ->md_handler.
+                * It is safe to drop the res_lock here as the
+                * caller has only just claimed it.
+                */
+               lnet_res_unlock(cpt);
+               schedule();
+               /* Cannot check md now, it might be freed.  Caller
+                * must reclaim reference and check.
+                */
+               lnet_res_lock(cpt);
+       }
+       finish_wait(wq, wqe);
+}
+
 static inline void
 lnet_md_free(struct lnet_libmd *md)
 {