diff options
| author |   Gregory CLEMENT <gregory.clement@free-electrons.com> | 2016-02-04 22:09:24 +0100 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2016-02-13 06:02:18 -0500 |
| commit | cad5d847a093077b499a8b0bbfe6804b9226c03e (patch) | |
| tree | a1355e0c243c7b4ebbb52c7a0ce3d1c93f7a1edc /drivers/net/ethernet/marvell | |
| parent | net: mvneta: Fix for_each_present_cpu usage (diff) | |
| download | linux-dev-cad5d847a093077b499a8b0bbfe6804b9226c03e.tar.xz linux-dev-cad5d847a093077b499a8b0bbfe6804b9226c03e.zip | |
net: mvneta: Fix the CPU choice in mvneta_percpu_elect
When passing to the management of multiple RX queue, the
mvneta_percpu_elect function was broken. The use of the modulo can lead
to elect the wrong cpu. For example with rxq_def=2, if the CPU 2 goes
offline and then online, we ended with the third RX queue activated in
the same time on CPU 0 and CPU2, which lead to a kernel crash.
With this fix, we don't try to get "the closer" CPU if the default CPU is
gone, now we just use CPU 0 which always be there. Thanks to this, the
code becomes more readable, easier to maintain and more predicable.
Cc: stable@vger.kernel.org
Fixes: 2dcf75e2793c ("net: mvneta: Associate RX queues with each CPU")
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/marvell')
| -rw-r--r-- | drivers/net/ethernet/marvell/mvneta.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c index 90ff5c7e19ea..4c2d12423750 100644 --- a/drivers/net/ethernet/marvell/mvneta.c +++ b/drivers/net/ethernet/marvell/mvneta.c @@ -2849,9 +2849,14 @@ static void mvneta_percpu_disable(void *arg) static void mvneta_percpu_elect(struct mvneta_port *pp) { - int online_cpu_idx, max_cpu, cpu, i = 0; + int elected_cpu = 0, max_cpu, cpu, i = 0; + + /* Use the cpu associated to the rxq when it is online, in all + * the other cases, use the cpu 0 which can't be offline. + */ + if (cpu_online(pp->rxq_def)) + elected_cpu = pp->rxq_def; - online_cpu_idx = pp->rxq_def % num_online_cpus(); max_cpu = num_present_cpus(); for_each_online_cpu(cpu) { @@ -2862,7 +2867,7 @@ static void mvneta_percpu_elect(struct mvneta_port *pp) if ((rxq % max_cpu) == cpu) rxq_map |= MVNETA_CPU_RXQ_ACCESS(rxq); - if (i == online_cpu_idx) + if (cpu == elected_cpu) /* Map the default receive queue queue to the * elected CPU */ @@ -2873,7 +2878,7 @@ static void mvneta_percpu_elect(struct mvneta_port *pp) * the CPU bound to the default RX queue */ if (txq_number == 1) - txq_map = (i == online_cpu_idx) ? + txq_map = (cpu == elected_cpu) ? MVNETA_CPU_TXQ_ACCESS(1) : 0; else txq_map = mvreg_read(pp, MVNETA_CPU_MAP(cpu)) & |