LU-10428 lnet: call event handlers without res_lock

[fs/lustre-release.git] / lnet / lnet / lib-md.c

diff --git a/lnet/lnet/lib-md.c b/lnet/lnet/lib-md.c
index 61db468..bc10b4a 100644 (file)
--- a/lnet/lnet/lib-md.c
+++ b/lnet/lnet/lib-md.c
@@ -70,6 +70,7 @@ lnet_md_unlink(struct lnet_libmd *md)
 
        LASSERT(!list_empty(&md->md_list));
        list_del_init(&md->md_list);
+       LASSERT(!(md->md_flags & LNET_MD_FLAG_HANDLING));
        lnet_md_free(md);
 }
 
@@ -473,18 +474,26 @@ int
 LNetMDUnlink(struct lnet_handle_md mdh)
 {
        struct lnet_event ev;
-       struct lnet_libmd *md;
+       struct lnet_libmd *md = NULL;
+       lnet_handler_t handler = NULL;
        int cpt;
 
        LASSERT(the_lnet.ln_refcount > 0);
 
        cpt = lnet_cpt_of_cookie(mdh.cookie);
        lnet_res_lock(cpt);
-
-       md = lnet_handle2md(&mdh);
-       if (md == NULL) {
-               lnet_res_unlock(cpt);
-               return -ENOENT;
+       while (!md) {
+               md = lnet_handle2md(&mdh);
+               if (!md) {
+                       lnet_res_unlock(cpt);
+                       return -ENOENT;
+               }
+               if (md->md_refcount == 0 &&
+                   md->md_flags & LNET_MD_FLAG_HANDLING) {
+                       /* Race with unlocked call to ->md_handler. */
+                       lnet_md_wait_handling(md, cpt);
+                       md = NULL;
+               }
        }
 
        md->md_flags |= LNET_MD_FLAG_ABORTED;
@@ -493,7 +502,7 @@ LNetMDUnlink(struct lnet_handle_md mdh)
         * unlinked. Otherwise, we enqueue an event now... */
        if (md->md_handler && md->md_refcount == 0) {
                lnet_build_unlink_event(md, &ev);
-               md->md_handler(&ev);
+               handler = md->md_handler;
        }
 
        if (md->md_rspt_ptr != NULL)
@@ -502,6 +511,10 @@ LNetMDUnlink(struct lnet_handle_md mdh)
        lnet_md_unlink(md);
 
        lnet_res_unlock(cpt);
+
+       if (handler)
+               handler(&ev);
+
        return 0;
 }
 EXPORT_SYMBOL(LNetMDUnlink);