diff options
Diffstat (limited to 'target/linux/mvebu/patches-4.4/041-net-mvneta-The-mvneta_percpu_elect-function-should-b.patch')
| -rw-r--r-- | target/linux/mvebu/patches-4.4/041-net-mvneta-The-mvneta_percpu_elect-function-should-b.patch | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/target/linux/mvebu/patches-4.4/041-net-mvneta-The-mvneta_percpu_elect-function-should-b.patch b/target/linux/mvebu/patches-4.4/041-net-mvneta-The-mvneta_percpu_elect-function-should-b.patch new file mode 100644 index 0000000000..a77bef44e4 --- /dev/null +++ b/target/linux/mvebu/patches-4.4/041-net-mvneta-The-mvneta_percpu_elect-function-should-b.patch @@ -0,0 +1,68 @@ +From: Gregory CLEMENT <gregory.clement@free-electrons.com> +Date: Thu, 4 Feb 2016 22:09:28 +0100 +Subject: [PATCH] net: mvneta: The mvneta_percpu_elect function should be + atomic + +Electing a CPU must be done in an atomic way: it should be done after or +before the removal/insertion of a CPU and this function is not reentrant. + +During the loop of mvneta_percpu_elect we associates the queues to the +CPUs, if there is a topology change during this loop, then the mapping +between the CPUs and the queues could be wrong. During this loop the +interrupt mask is also updating for each CPUs, It should not be changed +in the same time by other part of the driver. + +This patch adds spinlock to create the needed critical sections. + +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 +@@ -370,6 +370,10 @@ struct mvneta_port { + struct net_device *dev; + struct notifier_block cpu_notifier; + int rxq_def; ++ /* Protect the access to the percpu interrupt registers, ++ * ensuring that the configuration remains coherent. ++ */ ++ spinlock_t lock; + + /* Core clock */ + struct clk *clk; +@@ -2853,6 +2857,12 @@ static void mvneta_percpu_elect(struct m + { + int elected_cpu = 0, max_cpu, cpu, i = 0; + ++ /* Electing a CPU must be done in an atomic way: it should be ++ * done after or before the removal/insertion of a CPU and ++ * this function is not reentrant. ++ */ ++ spin_lock(&pp->lock); ++ + /* 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. + */ +@@ -2896,6 +2906,7 @@ static void mvneta_percpu_elect(struct m + i++; + + } ++ spin_unlock(&pp->lock); + }; + + static int mvneta_percpu_notifier(struct notifier_block *nfb, +@@ -2950,8 +2961,13 @@ static int mvneta_percpu_notifier(struct + case CPU_DOWN_PREPARE: + case CPU_DOWN_PREPARE_FROZEN: + netif_tx_stop_all_queues(pp->dev); ++ /* Thanks to this lock we are sure that any pending ++ * cpu election is done ++ */ ++ spin_lock(&pp->lock); + /* Mask all ethernet port interrupts */ + on_each_cpu(mvneta_percpu_mask_interrupt, pp, true); ++ spin_unlock(&pp->lock); + + napi_synchronize(&port->napi); + napi_disable(&port->napi); |