From: Mr NeilBrown <neilb@suse.de>
Date: Sun, 24 Nov 2019 23:00:48 +0000 (+1100)
Subject: LU-12678 lnet: discard lnd_refcount
X-Git-Tag: 2.13.51~74
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=6062999295090244874594db69a3dffa6f4f8a53;p=fs%2Flustre-release.git

LU-12678 lnet: discard lnd_refcount

The lnd_refcount in 'struct lnet_lnd' is never tested (except
in an ASSERT()), so it cannot be needed.  Let's remove it.

Each individual lnd keeps track of how many lnet_ni are
registered for that lnd e.g. ksocklnd has a counter in ksnd_nnets
and o2iblnd has a linked list in kib_devs.
They hold a reference on the module while there are registered
devices, and the lnd is only freed (and the lnd_refcount checked)
when the module is unloaded.  This confirms that lnd_refcount
adds no value.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I0d0c04051bf01a1fa77d888b00fb0a7875b09ccd
Reviewed-on: https://review.whamcloud.com/36829
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <hornc@cray.com>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---

diff --git a/lnet/include/lnet/lib-types.h b/lnet/include/lnet/lib-types.h
index 5590503..562dc37 100644
--- a/lnet/include/lnet/lib-types.h
+++ b/lnet/include/lnet/lib-types.h
@@ -250,7 +250,6 @@ struct socket;
 struct lnet_lnd {
 	/* fields managed by portals */
 	struct list_head	lnd_list;	/* stash in the LND table */
-	int			lnd_refcount;	/* # active instances */
 
 	/* fields initialized by the LND */
 	__u32			lnd_type;
diff --git a/lnet/lnet/api-ni.c b/lnet/lnet/api-ni.c
index e3aa9bf..d6e5e3d 100644
--- a/lnet/lnet/api-ni.c
+++ b/lnet/lnet/api-ni.c
@@ -828,7 +828,6 @@ lnet_register_lnd(struct lnet_lnd *lnd)
 	LASSERT(lnet_find_lnd_by_type(lnd->lnd_type) == NULL);
 
 	list_add_tail(&lnd->lnd_list, &the_lnet.ln_lnds);
-	lnd->lnd_refcount = 0;
 
 	CDEBUG(D_NET, "%s LND registered\n", libcfs_lnd2str(lnd->lnd_type));
 
@@ -842,7 +841,6 @@ lnet_unregister_lnd(struct lnet_lnd *lnd)
 	mutex_lock(&the_lnet.ln_lnd_mutex);
 
 	LASSERT(lnet_find_lnd_by_type(lnd->lnd_type) == lnd);
-	LASSERT(lnd->lnd_refcount == 0);
 
 	list_del(&lnd->lnd_list);
 	CDEBUG(D_NET, "%s LND unregistered\n", libcfs_lnd2str(lnd->lnd_type));
@@ -2128,15 +2126,6 @@ lnet_shutdown_lndnet(struct lnet_net *net)
 	/* Do peer table cleanup for this net */
 	lnet_peer_tables_cleanup(net);
 
-	lnet_net_lock(LNET_LOCK_EX);
-	/*
-	 * decrement ref count on lnd only when the entire network goes
-	 * away
-	 */
-	net->net_lnd->lnd_refcount--;
-
-	lnet_net_unlock(LNET_LOCK_EX);
-
 	lnet_net_free(net);
 }
 
@@ -2220,9 +2209,6 @@ lnet_startup_lndni(struct lnet_ni *ni, struct lnet_lnd_tunables *tun)
 	if (rc != 0) {
 		LCONSOLE_ERROR_MSG(0x105, "Error %d starting up LNI %s\n",
 				   rc, libcfs_lnd2str(net->net_lnd->lnd_type));
-		lnet_net_lock(LNET_LOCK_EX);
-		net->net_lnd->lnd_refcount--;
-		lnet_net_unlock(LNET_LOCK_EX);
 		goto failed0;
 	}
 
@@ -2331,10 +2317,6 @@ lnet_startup_lndnet(struct lnet_net *net, struct lnet_lnd_tunables *tun)
 			}
 		}
 
-		lnet_net_lock(LNET_LOCK_EX);
-		lnd->lnd_refcount++;
-		lnet_net_unlock(LNET_LOCK_EX);
-
 		net->net_lnd = lnd;
 
 		mutex_unlock(&the_lnet.ln_lnd_mutex);