From 0de624aa4719ab43ea5465a4d34fd28d577f915d Mon Sep 17 00:00:00 2001
From: shurd <shurd@FreeBSD.org>
Date: Wed, 29 Nov 2017 18:14:57 +0000
Subject: [PATCH] Ensure that ctx->ifc_cpus is always initialized

If a device didn't support MSI-X, ctx->ifc_cpus would not be initialized,
but the IRQ allocation routines still uses the value.  Move the
initialization to common code.

Sponsored by:	Limelight Networks
---
 sys/net/iflib.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/sys/net/iflib.c b/sys/net/iflib.c
index c1ee25d5c0d4..2175bab7194c 100644
--- a/sys/net/iflib.c
+++ b/sys/net/iflib.c
@@ -4259,6 +4259,14 @@ iflib_device_register(device_t dev, void *sc, if_shared_ctx_t sctx, if_ctx_t *ct
 	GROUPTASK_INIT(&ctx->ifc_admin_task, 0, _task_fn_admin, ctx);
 	/* XXX format name */
 	taskqgroup_attach(qgroup_if_config_tqg, &ctx->ifc_admin_task, ctx, -1, "admin");
+
+	/* Set up cpu set.  If it fails, zero out the set. */
+	if (bus_get_cpus(dev, INTR_CPUS, sizeof(ctx->ifc_cpus), &ctx->ifc_cpus) != 0) {
+		device_printf(dev, "Unable to fetch CPU list\n");
+		CPU_COPY(&all_cpus, &ctx->ifc_cpus);
+	}
+	MPASS(CPU_COUNT(&ctx->ifc_cpus) > 0);
+
 	/*
 	** Now setup MSI or MSI/X, should
 	** return us the number of supported
@@ -4984,7 +4992,7 @@ find_nth(if_ctx_t ctx, cpuset_t *cpus, int qid)
 	int i, cpuid, eqid, count;
 
 	CPU_COPY(&ctx->ifc_cpus, cpus);
-	count = CPU_COUNT(&ctx->ifc_cpus);
+	count = CPU_COUNT(cpus);
 	eqid = qid % count;
 	/* clear up to the qid'th bit */
 	for (i = 0; i < eqid; i++) {
@@ -5391,20 +5399,14 @@ iflib_msix_init(if_ctx_t ctx)
 #else
 	queuemsgs = msgs - admincnt;
 #endif
-	if (bus_get_cpus(dev, INTR_CPUS, sizeof(ctx->ifc_cpus), &ctx->ifc_cpus) == 0) {
 #ifdef RSS
-		queues = imin(queuemsgs, rss_getnumbuckets());
+	queues = imin(queuemsgs, rss_getnumbuckets());
 #else
-		queues = queuemsgs;
+	queues = queuemsgs;
 #endif
-		queues = imin(CPU_COUNT(&ctx->ifc_cpus), queues);
-		device_printf(dev, "pxm cpus: %d queue msgs: %d admincnt: %d\n",
-					  CPU_COUNT(&ctx->ifc_cpus), queuemsgs, admincnt);
-	} else {
-		device_printf(dev, "Unable to fetch CPU list\n");
-		/* Figure out a reasonable auto config value */
-		queues = min(queuemsgs, mp_ncpus);
-	}
+	queues = imin(CPU_COUNT(&ctx->ifc_cpus), queues);
+	device_printf(dev, "pxm cpus: %d queue msgs: %d admincnt: %d\n",
+				  CPU_COUNT(&ctx->ifc_cpus), queuemsgs, admincnt);
 #ifdef  RSS
 	/* If we're doing RSS, clamp at the number of RSS buckets */
 	if (queues > rss_getnumbuckets())