staging: lustre: startup lnet acceptor thread dynamically

With DLC it's possible to start up a system with no NIs that require
the acceptor thread, and thus it won't start.  Later on the user
can add an NI that requires the acceptor thread to start, it is
then necessary to start it up.

If the user removes a NI and as a result there are no more
NIs that require the acceptor thread then it should be stopped.
This patch adds logic in the dynamically adding and removing NIs
code to ensure the above logic is implemented.

Signed-off-by: Amir Shehata <amir.shehata@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6002
Reviewed-on: http://review.whamcloud.com/13010
Reviewed-by: Isaac Huang <he.huang@intel.com>
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lnet/lnet/acceptor.c b/drivers/staging/lustre/lnet/lnet/acceptor.c
index 07df727e0c56e2776427f0a8a366ef248c358a8e..9fe3ff7f90243ba297bf19cebd78b30c1b26e35b 100644 (file)
--- a/drivers/staging/lustre/lnet/lnet/acceptor.c
+++ b/drivers/staging/lustre/lnet/lnet/acceptor.c
@@ -46,7 +46,9 @@ static struct {
        int                     pta_shutdown;
        struct socket           *pta_sock;
        struct completion       pta_signal;
-} lnet_acceptor_state;
+} lnet_acceptor_state = {
+       .pta_shutdown = 1
+};
 
 int
 lnet_acceptor_port(void)
@@ -444,6 +446,10 @@ lnet_acceptor_start(void)
        long rc2;
        long secure;
 
+       /* if acceptor is already running return immediately */
+       if (!lnet_acceptor_state.pta_shutdown)
+               return 0;
+
        LASSERT(!lnet_acceptor_state.pta_sock);
 
        rc = lnet_acceptor_get_tunables();
@@ -484,7 +490,7 @@ lnet_acceptor_start(void)
 void
 lnet_acceptor_stop(void)
 {
-       if (!lnet_acceptor_state.pta_sock) /* not running */
+       if (lnet_acceptor_state.pta_shutdown) /* not running */
                return;
 
        lnet_acceptor_state.pta_shutdown = 1;

diff --git a/drivers/staging/lustre/lnet/lnet/api-ni.c b/drivers/staging/lustre/lnet/lnet/api-ni.c
index f223d5d5a6f389dc3554743ba7786c62fd998592..9497ce1cb4589425596640d4012c23909d0c16c2 100644 (file)
--- a/drivers/staging/lustre/lnet/lnet/api-ni.c
+++ b/drivers/staging/lustre/lnet/lnet/api-ni.c
@@ -1785,6 +1785,16 @@ lnet_dyn_add_ni(lnet_pid_t requested_pid, char *nets,
        if (rc)
                goto failed1;
 
+       if (ni->ni_lnd->lnd_accept) {
+               rc = lnet_acceptor_start();
+               if (rc < 0) {
+                       /* shutdown the ni that we just started */
+                       CERROR("Failed to start up acceptor thread\n");
+                       lnet_shutdown_lndni(ni);
+                       goto failed1;
+               }
+       }
+
        lnet_ping_target_update(pinfo, md_handle);
        mutex_unlock(&the_lnet.ln_api_mutex);
 
@@ -1832,6 +1842,10 @@ lnet_dyn_del_ni(__u32 net)
        lnet_ni_decref_locked(ni, 0);
 
        lnet_shutdown_lndni(ni);
+
+       if (!lnet_count_acceptor_nis())
+               lnet_acceptor_stop();
+
        lnet_ping_target_update(pinfo, md_handle);
        goto out;
 failed: