[lustre-devel] [PATCH 09/34] lnet: add list of cpts to lnet_net.

[NeilBrown]

struct lnet_net now has a list of cpts, which is the union
of the cpts for each lnet_ni.

This is part of
    8cbb8cd3e771e7f7e0f99cafc19fad32770dc015
       LU-7734 lnet: Multi-Rail local NI split

Signed-off-by: NeilBrown <neilb at suse.com>
---
 .../staging/lustre/include/linux/lnet/lib-types.h  |    6 +
 drivers/staging/lustre/lnet/lnet/config.c          |  164 ++++++++++++++++++++
 2 files changed, 170 insertions(+)

diff --git a/drivers/staging/lustre/include/linux/lnet/lib-types.h b/drivers/staging/lustre/include/linux/lnet/lib-types.h
index 2d2c066a11ba..22957d142cc0 100644
--- a/drivers/staging/lustre/include/linux/lnet/lib-types.h
+++ b/drivers/staging/lustre/include/linux/lnet/lib-types.h
@@ -266,6 +266,12 @@ struct lnet_net {
 	 * lnet/include/lnet/nidstr.h */
 	__u32			net_id;
 
+	/* total number of CPTs in the array */
+	__u32			net_ncpts;
+
+	/* cumulative CPTs of all NIs in this net */
+	__u32			*net_cpts;
+
 	/* network tunables */
 	struct lnet_ioctl_config_lnd_cmn_tunables net_tunables;
 
diff --git a/drivers/staging/lustre/lnet/lnet/config.c b/drivers/staging/lustre/lnet/lnet/config.c
index e83bdbec11e3..380a3fb1caba 100644
--- a/drivers/staging/lustre/lnet/lnet/config.c
+++ b/drivers/staging/lustre/lnet/lnet/config.c
@@ -91,11 +91,169 @@ lnet_net_unique(__u32 net, struct list_head *netlist)
 	return true;
 }
 
+static bool
+in_array(__u32 *array, __u32 size, __u32 value)
+{
+	int i;
+
+	for (i = 0; i < size; i++) {
+		if (array[i] == value)
+			return false;
+	}
+
+	return true;
+}
+
+static int
+lnet_net_append_cpts(__u32 *cpts, __u32 ncpts, struct lnet_net *net)
+{
+	__u32 *added_cpts = NULL;
+	int i, j = 0, rc = 0;
+
+	/*
+	 * no need to go futher since a subset of the NIs already exist on
+	 * all CPTs
+	 */
+	if (net->net_ncpts == LNET_CPT_NUMBER)
+		return 0;
+
+	if (cpts == NULL) {
+		/* there is an NI which will exist on all CPTs */
+		if (net->net_cpts != NULL)
+			kvfree(net->net_cpts);
+		net->net_cpts = NULL;
+		net->net_ncpts = LNET_CPT_NUMBER;
+		return 0;
+	}
+
+	if (net->net_cpts == NULL) {
+		net->net_cpts = kmalloc_array(ncpts, sizeof(net->net_cpts),
+					      GFP_KERNEL);
+		if (net->net_cpts == NULL)
+			return -ENOMEM;
+		memcpy(net->net_cpts, cpts, ncpts);
+		return 0;
+	}
+
+	added_cpts = kmalloc_array(LNET_CPT_NUMBER, sizeof(*added_cpts),
+				   GFP_KERNEL);
+	if (added_cpts == NULL)
+		return -ENOMEM;
+
+	for (i = 0; i < ncpts; i++) {
+		if (!in_array(net->net_cpts, net->net_ncpts, cpts[i])) {
+			added_cpts[j] = cpts[i];
+			j++;
+		}
+	}
+
+	/* append the new cpts if any to the list of cpts in the net */
+	if (j > 0) {
+		__u32 *array = NULL, *loc;
+		__u32 total_entries = j + net->net_ncpts;
+
+		array = kmalloc_array(total_entries, sizeof(*net->net_cpts),
+				      GFP_KERNEL);
+		if (array == NULL) {
+			rc = -ENOMEM;
+			goto failed;
+		}
+
+		memcpy(array, net->net_cpts,
+		       net->net_ncpts * sizeof(*net->net_cpts));
+		loc = array + net->net_ncpts;
+		memcpy(loc, added_cpts, j * sizeof(*net->net_cpts));
+
+		kfree(net->net_cpts);
+		net->net_ncpts = total_entries;
+		net->net_cpts = array;
+	}
+
+failed:
+	kfree(added_cpts);
+
+	return rc;
+}
+
+static void
+lnet_net_remove_cpts(__u32 *cpts, __u32 ncpts, struct lnet_net *net)
+{
+	struct lnet_ni *ni;
+	int rc;
+
+	/*
+	 * Operation Assumption:
+	 *	This function is called after an NI has been removed from
+	 *	its parent net.
+	 *
+	 * if we're removing an NI which exists on all CPTs then
+	 * we have to check if any of the other NIs on this net also
+	 * exists on all CPTs. If none, then we need to build our Net CPT
+	 * list based on the remaining NIs.
+	 *
+	 * If the NI being removed exist on a subset of the CPTs then we
+	 * alo rebuild the Net CPT list based on the remaining NIs, which
+	 * should resutl in the expected Net CPT list.
+	 */
+
+	/*
+	 * sometimes this function can be called due to some failure
+	 * creating an NI, before any of the cpts are allocated, so check
+	 * for that case and don't do anything
+	 */
+	if (ncpts == 0)
+		return;
+
+	if (ncpts == LNET_CPT_NUMBER) {
+		/*
+		 * first iteration through the NI list in the net to see
+		 * if any of the NIs exist on all the CPTs. If one is
+		 * found then our job is done.
+		 */
+		list_for_each_entry(ni, &net->net_ni_list, ni_netlist) {
+			if (ni->ni_ncpts == LNET_CPT_NUMBER)
+				return;
+		}
+	}
+
+	/*
+	 * Rebuild the Net CPT list again, thereby only including only the
+	 * CPTs which the remaining NIs are associated with.
+	 */
+	if (net->net_cpts != NULL) {
+		kfree(net->net_cpts);
+		net->net_cpts = NULL;
+	}
+
+	list_for_each_entry(ni, &net->net_ni_list, ni_netlist) {
+		rc = lnet_net_append_cpts(ni->ni_cpts, ni->ni_ncpts,
+					  net);
+		if (rc != 0) {
+			CERROR("Out of Memory\n");
+			/*
+			 * do our best to keep on going. Delete
+			 * the net cpts and set it to NULL. This
+			 * way we can keep on going but less
+			 * efficiently, since memory accesses might be
+			 * accross CPT lines.
+			 */
+			if (net->net_cpts != NULL) {
+				kfree(net->net_cpts);
+				net->net_cpts = NULL;
+				net->net_ncpts = LNET_CPT_NUMBER;
+			}
+			return;
+		}
+	}
+}
+
 void
 lnet_ni_free(struct lnet_ni *ni)
 {
 	int i;
 
+	lnet_net_remove_cpts(ni->ni_cpts, ni->ni_ncpts, ni->ni_net);
+
 	if (ni->ni_refs)
 		cfs_percpt_free(ni->ni_refs);
 
@@ -128,6 +286,9 @@ lnet_net_free(struct lnet_net *net)
 		lnet_ni_free(ni);
 	}
 
+	if (net->net_cpts != NULL)
+		kfree(net->net_cpts);
+
 	kfree(net);
 }
 
@@ -229,6 +390,9 @@ lnet_ni_alloc(struct lnet_net *net, struct cfs_expr_list *el, char *iface)
 		ni->ni_net_ns = NULL;
 
 	ni->ni_last_alive = ktime_get_real_seconds();
+	rc = lnet_net_append_cpts(ni->ni_cpts, ni->ni_ncpts, net);
+	if (rc != 0)
+		goto failed;
 	list_add_tail(&ni->ni_netlist, &net->net_ni_list);
 
 	return ni;