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69 lines
2.3 KiB
69 lines
2.3 KiB
9 years ago
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From: Gregory CLEMENT <gregory.clement@free-electrons.com>
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Date: Thu, 4 Feb 2016 22:09:28 +0100
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Subject: [PATCH] net: mvneta: The mvneta_percpu_elect function should be
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atomic
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Electing a CPU must be done in an atomic way: it should be done after or
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before the removal/insertion of a CPU and this function is not reentrant.
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During the loop of mvneta_percpu_elect we associates the queues to the
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CPUs, if there is a topology change during this loop, then the mapping
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between the CPUs and the queues could be wrong. During this loop the
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interrupt mask is also updating for each CPUs, It should not be changed
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in the same time by other part of the driver.
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This patch adds spinlock to create the needed critical sections.
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Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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--- a/drivers/net/ethernet/marvell/mvneta.c
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+++ b/drivers/net/ethernet/marvell/mvneta.c
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@@ -370,6 +370,10 @@ struct mvneta_port {
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struct net_device *dev;
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struct notifier_block cpu_notifier;
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int rxq_def;
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+ /* Protect the access to the percpu interrupt registers,
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+ * ensuring that the configuration remains coherent.
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+ */
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+ spinlock_t lock;
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/* Core clock */
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struct clk *clk;
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@@ -2853,6 +2857,12 @@ static void mvneta_percpu_elect(struct m
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{
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int elected_cpu = 0, max_cpu, cpu, i = 0;
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+ /* Electing a CPU must be done in an atomic way: it should be
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+ * done after or before the removal/insertion of a CPU and
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+ * this function is not reentrant.
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+ */
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+ spin_lock(&pp->lock);
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+
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/* Use the cpu associated to the rxq when it is online, in all
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* the other cases, use the cpu 0 which can't be offline.
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*/
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@@ -2896,6 +2906,7 @@ static void mvneta_percpu_elect(struct m
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i++;
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}
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+ spin_unlock(&pp->lock);
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};
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static int mvneta_percpu_notifier(struct notifier_block *nfb,
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@@ -2950,8 +2961,13 @@ static int mvneta_percpu_notifier(struct
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case CPU_DOWN_PREPARE:
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case CPU_DOWN_PREPARE_FROZEN:
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netif_tx_stop_all_queues(pp->dev);
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+ /* Thanks to this lock we are sure that any pending
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+ * cpu election is done
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+ */
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+ spin_lock(&pp->lock);
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/* Mask all ethernet port interrupts */
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on_each_cpu(mvneta_percpu_mask_interrupt, pp, true);
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+ spin_unlock(&pp->lock);
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napi_synchronize(&port->napi);
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napi_disable(&port->napi);
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