staging: lustre: lnet: enable configuration per NI interface

Add the ability to configure each NI interface at bring up.
Also give the ability for user land utilities to query the
configuration of each NI interface.

Signed-off-by: Amir Shehata <[e-mail]>
Signed-off-by: James Simmons <[e-mail]>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7101
Reviewed-on: http://review.whamcloud.com/16367
Reviewed-by: Doug Oucharek <[e-mail]>
Reviewed-by: Olaf Weber <[e-mail]>
Reviewed-by: Oleg Drokin <[e-mail]>
Signed-off-by: James Simmons <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/lustre/lnet/lnet/api-ni.c

···
 static int
 lnet_startup_lndni(struct lnet_ni *ni, struct lnet_ioctl_config_data *conf)
 {
+	struct lnet_ioctl_config_lnd_tunables *lnd_tunables = NULL;
 	int rc = -EINVAL;
 	int lnd_type;
 	lnd_t *lnd;
···
 	lnet_net_unlock(LNET_LOCK_EX);
 
 	ni->ni_lnd = lnd;
+
+	if (conf && conf->cfg_hdr.ioc_len > sizeof(*conf))
+		lnd_tunables = (struct lnet_ioctl_config_lnd_tunables *)conf->cfg_bulk;
+
+	if (lnd_tunables) {
+		LIBCFS_ALLOC(ni->ni_lnd_tunables,
+			     sizeof(*ni->ni_lnd_tunables));
+		if (!ni->ni_lnd_tunables) {
+			mutex_unlock(&the_lnet.ln_lnd_mutex);
+			rc = -ENOMEM;
+			goto failed0;
+		}
+		memcpy(ni->ni_lnd_tunables, lnd_tunables,
+		       sizeof(*ni->ni_lnd_tunables));
+	}
 
 	rc = lnd->lnd_startup(ni);
 
···
 static void
 lnet_fill_ni_info(struct lnet_ni *ni, struct lnet_ioctl_config_data *config)
 {
+	struct lnet_ioctl_config_lnd_tunables *lnd_cfg = NULL;
 	struct lnet_ioctl_net_config *net_config;
+	size_t min_size, tunable_size = 0;
 	int i;
 
 	if (!ni || !config)
···
 			net_config->ni_cpts[i] = ni->ni_cpts[i];
 
 		config->cfg_ncpts = num_cpts;
+	}
+
+	/*
+	 * See if user land tools sent in a newer and larger version
+	 * of struct lnet_tunables than what the kernel uses.
+	 */
+	min_size = sizeof(*config) + sizeof(*net_config);
+
+	if (config->cfg_hdr.ioc_len > min_size)
+		tunable_size = config->cfg_hdr.ioc_len - min_size;
+
+	/* Don't copy to much data to user space */
+	min_size = min(tunable_size, sizeof(*ni->ni_lnd_tunables));
+	lnd_cfg = (struct lnet_ioctl_config_lnd_tunables *)net_config->cfg_bulk;
+
+	if (ni->ni_lnd_tunables && lnd_cfg && min_size) {
+		memcpy(lnd_cfg, ni->ni_lnd_tunables, min_size);
+		config->cfg_config_u.cfg_net.net_interface_count = 1;
+
+		/* Tell user land that kernel side has less data */
+		if (tunable_size > sizeof(*ni->ni_lnd_tunables)) {
+			min_size = tunable_size - sizeof(ni->ni_lnd_tunables);
+			config->cfg_hdr.ioc_len -= min_size;
+		}
 	}
 }