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rt2x00: Fix PCI interrupt processing race on SMP systems

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When toggle_irq is called for PCI devices to disable device interrupts
it used tasklet_disable to wait for a possibly running tasklet to finish.
However, on SMP systems the tasklet might still be scheduled on another CPU.
Instead, use tasklet_kill to ensure that all scheduled tasklets are finished
before returning from toggle_irq.

Furthermore, it was possible that a tasklet reenabled its interrupt even
though interrupts have been disabled already. Fix this by checking the
DEVICE_STATE_ENABLED_RADIO flag before reenabling single interrupts
during tasklet processing.

While at it also enable/kill the TBTT and PRETBTT tasklets in the
toggle_irq callback and only use tasklet_kill in stop_queue to wait
for a currently scheduled beacon update before returning.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Helmut Schaa
2011-08-06 13:13:48 +02:00
committed by John W. Linville
parent c3ccb3341e
commit abc1199411
5 changed files with 64 additions and 95 deletions
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34
drivers/net/wireless/rt2x00/rt61pci.c
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@@ -1142,11 +1142,6 @@ static void rt61pci_start_queue(struct data_queue *queue)
rt2x00pci_register_write(rt2x00dev, TXRX_CSR0, reg);
break;
case QID_BEACON:
/*
* Allow the tbtt tasklet to be scheduled.
*/
tasklet_enable(&rt2x00dev->tbtt_tasklet);
rt2x00pci_register_read(rt2x00dev, TXRX_CSR9, &reg);
rt2x00_set_field32(&reg, TXRX_CSR9_TSF_TICKING, 1);
rt2x00_set_field32(&reg, TXRX_CSR9_TBTT_ENABLE, 1);
@@ -1230,7 +1225,7 @@ static void rt61pci_stop_queue(struct data_queue *queue)
/*
* Wait for possibly running tbtt tasklets.
*/
tasklet_disable(&rt2x00dev->tbtt_tasklet);
tasklet_kill(&rt2x00dev->tbtt_tasklet);
break;
default:
break;
@@ -1731,13 +1726,6 @@ static void rt61pci_toggle_irq(struct rt2x00_dev *rt2x00dev,
rt2x00pci_register_read(rt2x00dev, MCU_INT_SOURCE_CSR, &reg);
rt2x00pci_register_write(rt2x00dev, MCU_INT_SOURCE_CSR, reg);
/*
* Enable tasklets.
*/
tasklet_enable(&rt2x00dev->txstatus_tasklet);
tasklet_enable(&rt2x00dev->rxdone_tasklet);
tasklet_enable(&rt2x00dev->autowake_tasklet);
}
/*
@@ -1772,9 +1760,10 @@ static void rt61pci_toggle_irq(struct rt2x00_dev *rt2x00dev,
/*
* Ensure that all tasklets are finished.
*/
tasklet_disable(&rt2x00dev->txstatus_tasklet);
tasklet_disable(&rt2x00dev->rxdone_tasklet);
tasklet_disable(&rt2x00dev->autowake_tasklet);
tasklet_kill(&rt2x00dev->txstatus_tasklet);
tasklet_kill(&rt2x00dev->rxdone_tasklet);
tasklet_kill(&rt2x00dev->autowake_tasklet);
tasklet_kill(&rt2x00dev->tbtt_tasklet);
}
}
@@ -2300,22 +2289,24 @@ static void rt61pci_txstatus_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
rt61pci_txdone(rt2x00dev);
rt61pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_TXDONE);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt61pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_TXDONE);
}
static void rt61pci_tbtt_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
rt2x00lib_beacondone(rt2x00dev);
rt61pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_BEACON_DONE);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt61pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_BEACON_DONE);
}
static void rt61pci_rxdone_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
if (rt2x00pci_rxdone(rt2x00dev))
rt2x00pci_rxdone(rt2x00dev);
else
tasklet_schedule(&rt2x00dev->rxdone_tasklet);
else if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt61pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_RXDONE);
}
@@ -2325,7 +2316,8 @@ static void rt61pci_autowake_tasklet(unsigned long data)
rt61pci_wakeup(rt2x00dev);
rt2x00pci_register_write(rt2x00dev,
M2H_CMD_DONE_CSR, 0xffffffff);
rt61pci_enable_mcu_interrupt(rt2x00dev, MCU_INT_MASK_CSR_TWAKEUP);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt61pci_enable_mcu_interrupt(rt2x00dev, MCU_INT_MASK_CSR_TWAKEUP);
}
static irqreturn_t rt61pci_interrupt(int irq, void *dev_instance)