staging: lustre: improve LNet clean up code and API

This patch addresses a set of related issues: LU-5568, LU-5734,
LU-5839, LU-5849, LU-5850.

Create the local lnet_startup_lndni() API.  This function starts
up one LND.  lnet_startup_lndnis() calls this function in a loop
on every ni in the list passed in.  lnet_startup_lndni() is
responsible for cleaning up after itself in case of failure.
It calls lnet_free_ni() if the ni fails to start.  It calls
lnet_shutdown_lndni() if it successfully called the
lnd startup function, but fails later on.

lnet_startup_lndnis() also cleans up after itself.
If lnet_startup_lndni() fails then lnet_shutdown_lndnis() is
called to clean up all nis that might have been
started, and then free the rest of the nis on the list
which have not been started yet.

To facilitate the above changes lnet_dyn_del_ni() now
manages the ping info.  It calls lnet_shutdown_lndni(),
to shutdown the NI.  lnet_shutdown_lndni() is no longer
an exposed API and doesn't manage the ping info, making
it callable from lnet_startup_lndni() as well.

There are two scenarios for calling lnet_startup_lndni()

1. from lnet_startup_lndnis()
If lnet_startup_lndni() fails it requires to shutdown the ni
without doing anything with the ping information as it hasn't
been created yet.

2. from lnet_dyn_add_ni()
As above it will shutdown the ni, and then lnet_dyn_add_ni() will
take care of managing the ping info

The second part of this change is to ensure that the LOLND is not
added by lnet_parse_networks(), but the caller which needs to do
it (IE: LNetNIInit)

This change ensures that lnet_dyn_add_ni() need only check if there is
only one net that's being added, if not then it frees everything,
otherwise it proceeds to startup the requested net.
Signed-off-by: Amir Shehata <amir.shehata@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5734
Reviewed-on: http://review.whamcloud.com/12658Reviewed-by: Liang Zhen <liang.zhen@intel.com>
Reviewed-by: Isaac Huang <he.huang@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/include/linux/lnet/lib-lnet.h

@@ -422,6 +422,8 @@ lnet_ni_decref(lnet_ni_t *ni)
 }
 
 void lnet_ni_free(lnet_ni_t *ni);
+lnet_ni_t *
+lnet_ni_alloc(__u32 net, struct cfs_expr_list *el, struct list_head *nilist);
 
 static inline int
 lnet_nid2peerhash(lnet_nid_t nid)

drivers/staging/lustre/lnet/lnet/config.c

@@ -114,7 +114,7 @@ lnet_ni_free(struct lnet_ni *ni)
 	LIBCFS_FREE(ni, sizeof(*ni));
 }
 
-static lnet_ni_t *
+lnet_ni_t *
 lnet_ni_alloc(__u32 net, struct cfs_expr_list *el, struct list_head *nilist)
 {
 	struct lnet_tx_queue *tq;
@@ -191,6 +191,7 @@ lnet_parse_networks(struct list_head *nilist, char *networks)
 	struct lnet_ni *ni;
 	__u32 net;
 	int nnets = 0;
+	struct list_head *temp_node;
 
 	if (!networks) {
 		CERROR("networks string is undefined\n");
@@ -216,11 +217,6 @@ lnet_parse_networks(struct list_head *nilist, char *networks)
 	tmp = tokens;
 	str = tokens;
 
-	/* Add in the loopback network */
-	ni = lnet_ni_alloc(LNET_MKNET(LOLND, 0), NULL, nilist);
-	if (!ni)
-		goto failed;
-
 	while (str && *str) {
 		char *comma = strchr(str, ',');
 		char *bracket = strchr(str, '(');
@@ -294,7 +290,6 @@ lnet_parse_networks(struct list_head *nilist, char *networks)
 			goto failed_syntax;
 		}
 
-		nnets++;
 		ni = lnet_ni_alloc(net, el, nilist);
 		if (!ni)
 			goto failed;
@@ -372,10 +367,11 @@ lnet_parse_networks(struct list_head *nilist, char *networks)
 		}
 	}
 
-	LASSERT(!list_empty(nilist));
+	list_for_each(temp_node, nilist)
+		nnets++;
 
 	LIBCFS_FREE(tokens, tokensize);
-	return 0;
+	return nnets;
 
  failed_syntax:
 	lnet_syntax("networks", networks, (int)(tmp - tokens), strlen(tmp));