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authorPeter Zijlstra <peterz@infradead.org>2021-06-11 11:28:11 +0300
committerPeter Zijlstra <peterz@infradead.org>2021-06-18 12:43:06 +0300
commit37aadc687ab441bbcb693ddae613acf9afcea1ab (patch)
tree83a8142d60076d6742205e513fc0fac6c0435fa5 /drivers/net
parentb2c0931a07b7376c6291e0cfb347ad27f7b66263 (diff)
downloadlinux-37aadc687ab441bbcb693ddae613acf9afcea1ab.tar.xz
sched: Unbreak wakeups
Remove broken task->state references and let wake_up_process() DTRT. The anti-pattern in these patches breaks the ordering of ->state vs COND as described in the comment near set_current_state() and can lead to missed wakeups: (OoO load, observes RUNNING)<-. for (;;) { | t->state = UNINTERRUPTIBLE; | smp_mb(); ,-----> | (observes !COND) | / if (COND) ---------' | COND = 1; break; `- if (t->state != RUNNING) wake_up_process(t); // not done schedule(); // forever waiting } t->state = TASK_RUNNING; Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210611082838.160855222@infradead.org
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/ethernet/qualcomm/qca_spi.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/net/ethernet/qualcomm/qca_spi.c b/drivers/net/ethernet/qualcomm/qca_spi.c
index ab9b02574a15..0a6b8112b535 100644
--- a/drivers/net/ethernet/qualcomm/qca_spi.c
+++ b/drivers/net/ethernet/qualcomm/qca_spi.c
@@ -653,8 +653,7 @@ qcaspi_intr_handler(int irq, void *data)
struct qcaspi *qca = data;
qca->intr_req++;
- if (qca->spi_thread &&
- qca->spi_thread->state != TASK_RUNNING)
+ if (qca->spi_thread)
wake_up_process(qca->spi_thread);
return IRQ_HANDLED;
@@ -777,8 +776,7 @@ qcaspi_netdev_xmit(struct sk_buff *skb, struct net_device *dev)
netif_trans_update(dev);
- if (qca->spi_thread &&
- qca->spi_thread->state != TASK_RUNNING)
+ if (qca->spi_thread)
wake_up_process(qca->spi_thread);
return NETDEV_TX_OK;