From dd6ab49a9aebb5fbb85973d9a859d24daa5e2165 Mon Sep 17 00:00:00 2001
From: Vincenzo Maffione <vmaffione@FreeBSD.org>
Date: Sun, 6 Mar 2022 17:28:44 +0000
Subject: netmap: add a tunable for the maximum number of VALE switches

The new dev.netmap.max_bridges sysctl tunable can be set in
loader.conf(5) to change the default maximum number of VALE
switches that can be created. Current defaults is 8.

MFC after:	2 weeks
---
 sys/dev/netmap/netmap_bdg.c  |  4 ++--
 sys/dev/netmap/netmap_kern.h |  4 +++-
 sys/dev/netmap/netmap_vale.c | 13 +++++++++----
 3 files changed, 14 insertions(+), 7 deletions(-)

(limited to 'sys/dev/netmap')

diff --git a/sys/dev/netmap/netmap_bdg.c b/sys/dev/netmap/netmap_bdg.c
index 103a3b00762e..1d49a97eec12 100644
--- a/sys/dev/netmap/netmap_bdg.c
+++ b/sys/dev/netmap/netmap_bdg.c
@@ -1828,7 +1828,7 @@ netmap_init_bridges(void)
 #ifdef CONFIG_NET_NS
 	return netmap_bns_register();
 #else
-	nm_bridges = netmap_init_bridges2(NM_BRIDGES);
+	nm_bridges = netmap_init_bridges2(vale_max_bridges);
 	if (nm_bridges == NULL)
 		return ENOMEM;
 	return 0;
@@ -1841,6 +1841,6 @@ netmap_uninit_bridges(void)
 #ifdef CONFIG_NET_NS
 	netmap_bns_unregister();
 #else
-	netmap_uninit_bridges2(nm_bridges, NM_BRIDGES);
+	netmap_uninit_bridges2(nm_bridges, vale_max_bridges);
 #endif
 }
diff --git a/sys/dev/netmap/netmap_kern.h b/sys/dev/netmap/netmap_kern.h
index 5d8957241c21..f8d824f08ebb 100644
--- a/sys/dev/netmap/netmap_kern.h
+++ b/sys/dev/netmap/netmap_kern.h
@@ -1559,6 +1559,8 @@ int netmap_get_vale_na(struct nmreq_header *hdr, struct netmap_adapter **na,
 void *netmap_vale_create(const char *bdg_name, int *return_status);
 int netmap_vale_destroy(const char *bdg_name, void *auth_token);
 
+extern unsigned int vale_max_bridges;
+
 #else /* !WITH_VALE */
 #define netmap_bdg_learning(_1, _2, _3, _4)	0
 #define	netmap_get_vale_na(_1, _2, _3, _4)	0
@@ -1606,7 +1608,7 @@ extern struct nm_bridge *nm_bridges;
 #define netmap_bns_get()
 #define netmap_bns_put(_1)
 #define netmap_bns_getbridges(b, n) \
-	do { *b = nm_bridges; *n = NM_BRIDGES; } while (0)
+	do { *b = nm_bridges; *n = vale_max_bridges; } while (0)
 #endif
 
 /* Various prototypes */
diff --git a/sys/dev/netmap/netmap_vale.c b/sys/dev/netmap/netmap_vale.c
index aac4cfe6736a..7813984ad295 100644
--- a/sys/dev/netmap/netmap_vale.c
+++ b/sys/dev/netmap/netmap_vale.c
@@ -84,10 +84,9 @@ __FBSDID("$FreeBSD$");
 
 /*
  * system parameters (most of them in netmap_kern.h)
- * NM_BDG_NAME	prefix for switch port names, default "vale"
+ * NM_BDG_NAME		prefix for switch port names, default "vale"
  * NM_BDG_MAXPORTS	number of ports
- * NM_BRIDGES	max number of switches in the system.
- *	XXX should become a sysctl or tunable
+ * NM_BRIDGES		max number of switches in the system.
  *
  * Switch ports are named valeX:Y where X is the switch name and Y
  * is the port. If Y matches a physical interface name, the port is
@@ -115,10 +114,16 @@ __FBSDID("$FreeBSD$");
  * last packet in the block may overflow the size.
  */
 static int bridge_batch = NM_BDG_BATCH; /* bridge batch size */
+
+/* Max number of vale bridges (loader tunable). */
+unsigned int vale_max_bridges = NM_BRIDGES;
+
 SYSBEGIN(vars_vale);
 SYSCTL_DECL(_dev_netmap);
 SYSCTL_INT(_dev_netmap, OID_AUTO, bridge_batch, CTLFLAG_RW, &bridge_batch, 0,
 		"Max batch size to be used in the bridge");
+SYSCTL_UINT(_dev_netmap, OID_AUTO, max_bridges, CTLFLAG_RDTUN, &vale_max_bridges, 0,
+		"Max number of vale bridges");
 SYSEND;
 
 static int netmap_vale_vp_create(struct nmreq_header *hdr, struct ifnet *,
@@ -366,7 +371,7 @@ netmap_vale_list(struct nmreq_header *hdr)
 		j = req->nr_port_idx;
 
 		NMG_LOCK();
-		for (error = ENOENT; i < NM_BRIDGES; i++) {
+		for (error = ENOENT; i < vale_max_bridges; i++) {
 			b = bridges + i;
 			for ( ; j < NM_BDG_MAXPORTS; j++) {
 				if (b->bdg_ports[j] == NULL)
-- 
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