diff options
Diffstat (limited to 'target/linux/mvebu/patches-4.4/038-net-mvneta-Fix-the-CPU-choice-in-mvneta_percpu_elect.patch')
| -rw-r--r-- | target/linux/mvebu/patches-4.4/038-net-mvneta-Fix-the-CPU-choice-in-mvneta_percpu_elect.patch | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/target/linux/mvebu/patches-4.4/038-net-mvneta-Fix-the-CPU-choice-in-mvneta_percpu_elect.patch b/target/linux/mvebu/patches-4.4/038-net-mvneta-Fix-the-CPU-choice-in-mvneta_percpu_elect.patch new file mode 100644 index 0000000000..4fc9ccc76a --- /dev/null +++ b/target/linux/mvebu/patches-4.4/038-net-mvneta-Fix-the-CPU-choice-in-mvneta_percpu_elect.patch @@ -0,0 +1,57 @@ +From: Gregory CLEMENT <gregory.clement@free-electrons.com> +Date: Thu, 4 Feb 2016 22:09:24 +0100 +Subject: [PATCH] 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> +--- + +--- a/drivers/net/ethernet/marvell/mvneta.c ++++ b/drivers/net/ethernet/marvell/mvneta.c +@@ -2847,9 +2847,14 @@ static void mvneta_percpu_disable(void * + + 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) { +@@ -2860,7 +2865,7 @@ static void mvneta_percpu_elect(struct m + 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 + */ +@@ -2871,7 +2876,7 @@ static void mvneta_percpu_elect(struct m + * 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)) & |