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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.patch57
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)) &