svn commit: r290948 - head/sys/dev/vmware/vmxnet3

[John Baldwin]

Author: jhb
Date: Mon Nov 16 21:36:50 2015
New Revision: 290948
URL: https://svnweb.freebsd.org/changeset/base/290948

Log:
  Only use a power of 2 for the number of receive and transmit queues.
  Using other values causes VMXNET3_CMD_ENABLE to fail.  The Linux
  driver also enforces this restriction.
  
  Reviewed by:	bryanv
  MFC after:	1 week
  Sponsored by:	Norse
  Differential Revision:	https://reviews.freebsd.org/D4139

Modified:
  head/sys/dev/vmware/vmxnet3/if_vmx.c

Modified: head/sys/dev/vmware/vmxnet3/if_vmx.c
==============================================================================
--- head/sys/dev/vmware/vmxnet3/if_vmx.c	Mon Nov 16 21:36:15 2015	(r290947)
+++ head/sys/dev/vmware/vmxnet3/if_vmx.c	Mon Nov 16 21:36:50 2015	(r290948)
@@ -510,6 +510,13 @@ vmxnet3_check_version(struct vmxnet3_sof
 	return (0);
 }
 
+static int
+trunc_powerof2(int val)
+{
+
+	return (1U << (fls(val) - 1));
+}
+
 static void
 vmxnet3_initial_config(struct vmxnet3_softc *sc)
 {
@@ -520,14 +527,14 @@ vmxnet3_initial_config(struct vmxnet3_so
 		nqueue = VMXNET3_DEF_TX_QUEUES;
 	if (nqueue > mp_ncpus)
 		nqueue = mp_ncpus;
-	sc->vmx_max_ntxqueues = nqueue;
+	sc->vmx_max_ntxqueues = trunc_powerof2(nqueue);
 
 	nqueue = vmxnet3_tunable_int(sc, "rxnqueue", vmxnet3_default_rxnqueue);
 	if (nqueue > VMXNET3_MAX_RX_QUEUES || nqueue < 1)
 		nqueue = VMXNET3_DEF_RX_QUEUES;
 	if (nqueue > mp_ncpus)
 		nqueue = mp_ncpus;
-	sc->vmx_max_nrxqueues = nqueue;
+	sc->vmx_max_nrxqueues = trunc_powerof2(nqueue);
 
 	if (vmxnet3_tunable_int(sc, "mq_disable", vmxnet3_mq_disable)) {
 		sc->vmx_max_nrxqueues = 1;