LU-12678 lnet: fix small race in unloading klnd modules.

[fs/lustre-release.git] / lnet / lnet / api-ni.c

diff --git a/lnet/lnet/api-ni.c b/lnet/lnet/api-ni.c
index 2ccbecc..399acdb 100644 (file)
--- a/lnet/lnet/api-ni.c
+++ b/lnet/lnet/api-ni.c
@@ -550,11 +550,6 @@ lnet_init_locks(void)
        mutex_init(&the_lnet.ln_lnd_mutex);
 }
 
-static void
-lnet_fini_locks(void)
-{
-}
-
 struct kmem_cache *lnet_mes_cachep;       /* MEs kmem_cache */
 struct kmem_cache *lnet_small_mds_cachep;  /* <= LNET_SMALL_MD_SIZE bytes
                                            *  MDs kmem_cache */
@@ -643,8 +638,6 @@ lnet_destroy_locks(void)
                cfs_percpt_lock_free(the_lnet.ln_net_lock);
                the_lnet.ln_net_lock = NULL;
        }
-
-       lnet_fini_locks();
 }
 
 static int
@@ -2069,7 +2062,14 @@ lnet_clear_zombies_nis_locked(struct lnet_net *net)
                islo = ni->ni_net->net_lnd->lnd_type == LOLND;
 
                LASSERT(!in_interrupt());
+               /* Holding the mutex makes it safe for lnd_shutdown
+                * to call module_put(). Module unload cannot finish
+                * until lnet_unregister_lnd() completes, and that
+                * requires the mutex.
+                */
+               mutex_lock(&the_lnet.ln_lnd_mutex);
                (net->net_lnd->lnd_shutdown)(ni);
+               mutex_unlock(&the_lnet.ln_lnd_mutex);
 
                if (!islo)
                        CDEBUG(D_LNI, "Removed LNI %s\n",
@@ -3916,9 +3916,7 @@ LNetCtl(unsigned int cmd, void *arg)
                return 0;
 
        case IOC_LIBCFS_TESTPROTOCOMPAT:
-               lnet_net_lock(LNET_LOCK_EX);
                the_lnet.ln_testprotocompat = data->ioc_flags;
-               lnet_net_unlock(LNET_LOCK_EX);
                return 0;
 
        case IOC_LIBCFS_LNET_FAULT: