Skip to content

Commit

Permalink
rt2x00: Fix PCI interrupt processing race on SMP systems
Browse files Browse the repository at this point in the history 
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>
  • Loading branch information
Helmut Schaa authored and John W. Linville committed Aug 9, 2011
1 parent c3ccb33 commit abc1199
Show file tree
Hide file tree
Showing 5 changed files with 64 additions and 95 deletions.
39 changes: 16 additions & 23 deletions drivers/net/wireless/rt2x00/rt2400pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -645,11 +645,6 @@ static void rt2400pci_start_queue(struct data_queue *queue)
rt2x00pci_register_write(rt2x00dev, RXCSR0, reg);
break;
case QID_BEACON:
/*
* Allow the tbtt tasklet to be scheduled.
*/
tasklet_enable(&rt2x00dev->tbtt_tasklet);

rt2x00pci_register_read(rt2x00dev, CSR14, &reg);
rt2x00_set_field32(&reg, CSR14_TSF_COUNT, 1);
rt2x00_set_field32(&reg, CSR14_TBCN, 1);
Expand Down Expand Up @@ -715,7 +710,7 @@ static void rt2400pci_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;
Expand Down Expand Up @@ -982,12 +977,6 @@ static void rt2400pci_toggle_irq(struct rt2x00_dev *rt2x00dev,
if (state == STATE_RADIO_IRQ_ON) {
rt2x00pci_register_read(rt2x00dev, CSR7, &reg);
rt2x00pci_register_write(rt2x00dev, CSR7, reg);

/*
* Enable tasklets.
*/
tasklet_enable(&rt2x00dev->txstatus_tasklet);
tasklet_enable(&rt2x00dev->rxdone_tasklet);
}

/*
Expand All @@ -1011,8 +1000,9 @@ static void rt2400pci_toggle_irq(struct rt2x00_dev *rt2x00dev,
* Ensure that all tasklets are finished before
* disabling the interrupts.
*/
tasklet_disable(&rt2x00dev->txstatus_tasklet);
tasklet_disable(&rt2x00dev->rxdone_tasklet);
tasklet_kill(&rt2x00dev->txstatus_tasklet);
tasklet_kill(&rt2x00dev->rxdone_tasklet);
tasklet_kill(&rt2x00dev->tbtt_tasklet);
}
}

Expand Down Expand Up @@ -1347,30 +1337,33 @@ static void rt2400pci_txstatus_tasklet(unsigned long data)
/*
* Enable all TXDONE interrupts again.
*/
spin_lock_irq(&rt2x00dev->irqmask_lock);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags)) {
spin_lock_irq(&rt2x00dev->irqmask_lock);

rt2x00pci_register_read(rt2x00dev, CSR8, &reg);
rt2x00_set_field32(&reg, CSR8_TXDONE_TXRING, 0);
rt2x00_set_field32(&reg, CSR8_TXDONE_ATIMRING, 0);
rt2x00_set_field32(&reg, CSR8_TXDONE_PRIORING, 0);
rt2x00pci_register_write(rt2x00dev, CSR8, reg);
rt2x00pci_register_read(rt2x00dev, CSR8, &reg);
rt2x00_set_field32(&reg, CSR8_TXDONE_TXRING, 0);
rt2x00_set_field32(&reg, CSR8_TXDONE_ATIMRING, 0);
rt2x00_set_field32(&reg, CSR8_TXDONE_PRIORING, 0);
rt2x00pci_register_write(rt2x00dev, CSR8, reg);

spin_unlock_irq(&rt2x00dev->irqmask_lock);
spin_unlock_irq(&rt2x00dev->irqmask_lock);
}
}

static void rt2400pci_tbtt_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
rt2x00lib_beacondone(rt2x00dev);
rt2400pci_enable_interrupt(rt2x00dev, CSR8_TBCN_EXPIRE);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt2400pci_enable_interrupt(rt2x00dev, CSR8_TBCN_EXPIRE);
}

static void rt2400pci_rxdone_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
if (rt2x00pci_rxdone(rt2x00dev))
tasklet_schedule(&rt2x00dev->rxdone_tasklet);
else
else if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt2400pci_enable_interrupt(rt2x00dev, CSR8_RXDONE);
}

Expand Down
39 changes: 16 additions & 23 deletions drivers/net/wireless/rt2x00/rt2500pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -735,11 +735,6 @@ static void rt2500pci_start_queue(struct data_queue *queue)
rt2x00pci_register_write(rt2x00dev, RXCSR0, reg);
break;
case QID_BEACON:
/*
* Allow the tbtt tasklet to be scheduled.
*/
tasklet_enable(&rt2x00dev->tbtt_tasklet);

rt2x00pci_register_read(rt2x00dev, CSR14, &reg);
rt2x00_set_field32(&reg, CSR14_TSF_COUNT, 1);
rt2x00_set_field32(&reg, CSR14_TBCN, 1);
Expand Down Expand Up @@ -805,7 +800,7 @@ static void rt2500pci_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;
Expand Down Expand Up @@ -1137,12 +1132,6 @@ static void rt2500pci_toggle_irq(struct rt2x00_dev *rt2x00dev,
if (state == STATE_RADIO_IRQ_ON) {
rt2x00pci_register_read(rt2x00dev, CSR7, &reg);
rt2x00pci_register_write(rt2x00dev, CSR7, reg);

/*
* Enable tasklets.
*/
tasklet_enable(&rt2x00dev->txstatus_tasklet);
tasklet_enable(&rt2x00dev->rxdone_tasklet);
}

/*
Expand All @@ -1165,8 +1154,9 @@ static void rt2500pci_toggle_irq(struct rt2x00_dev *rt2x00dev,
/*
* Ensure that all tasklets are finished.
*/
tasklet_disable(&rt2x00dev->txstatus_tasklet);
tasklet_disable(&rt2x00dev->rxdone_tasklet);
tasklet_kill(&rt2x00dev->txstatus_tasklet);
tasklet_kill(&rt2x00dev->rxdone_tasklet);
tasklet_kill(&rt2x00dev->tbtt_tasklet);
}
}

Expand Down Expand Up @@ -1479,30 +1469,33 @@ static void rt2500pci_txstatus_tasklet(unsigned long data)
/*
* Enable all TXDONE interrupts again.
*/
spin_lock_irq(&rt2x00dev->irqmask_lock);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags)) {
spin_lock_irq(&rt2x00dev->irqmask_lock);

rt2x00pci_register_read(rt2x00dev, CSR8, &reg);
rt2x00_set_field32(&reg, CSR8_TXDONE_TXRING, 0);
rt2x00_set_field32(&reg, CSR8_TXDONE_ATIMRING, 0);
rt2x00_set_field32(&reg, CSR8_TXDONE_PRIORING, 0);
rt2x00pci_register_write(rt2x00dev, CSR8, reg);
rt2x00pci_register_read(rt2x00dev, CSR8, &reg);
rt2x00_set_field32(&reg, CSR8_TXDONE_TXRING, 0);
rt2x00_set_field32(&reg, CSR8_TXDONE_ATIMRING, 0);
rt2x00_set_field32(&reg, CSR8_TXDONE_PRIORING, 0);
rt2x00pci_register_write(rt2x00dev, CSR8, reg);

spin_unlock_irq(&rt2x00dev->irqmask_lock);
spin_unlock_irq(&rt2x00dev->irqmask_lock);
}
}

static void rt2500pci_tbtt_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
rt2x00lib_beacondone(rt2x00dev);
rt2500pci_enable_interrupt(rt2x00dev, CSR8_TBCN_EXPIRE);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt2500pci_enable_interrupt(rt2x00dev, CSR8_TBCN_EXPIRE);
}

static void rt2500pci_rxdone_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
if (rt2x00pci_rxdone(rt2x00dev))
tasklet_schedule(&rt2x00dev->rxdone_tasklet);
else
else if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt2500pci_enable_interrupt(rt2x00dev, CSR8_RXDONE);
}

Expand Down
46 changes: 19 additions & 27 deletions drivers/net/wireless/rt2x00/rt2800pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -200,13 +200,6 @@ static void rt2800pci_start_queue(struct data_queue *queue)
rt2x00pci_register_write(rt2x00dev, MAC_SYS_CTRL, reg);
break;
case QID_BEACON:
/*
* Allow beacon tasklets to be scheduled for periodic
* beacon updates.
*/
tasklet_enable(&rt2x00dev->tbtt_tasklet);
tasklet_enable(&rt2x00dev->pretbtt_tasklet);

rt2x00pci_register_read(rt2x00dev, BCN_TIME_CFG, &reg);
rt2x00_set_field32(&reg, BCN_TIME_CFG_TSF_TICKING, 1);
rt2x00_set_field32(&reg, BCN_TIME_CFG_TBTT_ENABLE, 1);
Expand Down Expand Up @@ -269,10 +262,13 @@ static void rt2800pci_stop_queue(struct data_queue *queue)
rt2x00pci_register_write(rt2x00dev, INT_TIMER_EN, reg);

/*
* Wait for tbtt tasklets to finish.
* Wait for current invocation to finish. The tasklet
* won't be scheduled anymore afterwards since we disabled
* the TBTT and PRE TBTT timer.
*/
tasklet_disable(&rt2x00dev->tbtt_tasklet);
tasklet_disable(&rt2x00dev->pretbtt_tasklet);
tasklet_kill(&rt2x00dev->tbtt_tasklet);
tasklet_kill(&rt2x00dev->pretbtt_tasklet);

break;
default:
break;
Expand Down Expand Up @@ -437,14 +433,6 @@ static void rt2800pci_toggle_irq(struct rt2x00_dev *rt2x00dev,
if (state == STATE_RADIO_IRQ_ON) {
rt2x00pci_register_read(rt2x00dev, INT_SOURCE_CSR, &reg);
rt2x00pci_register_write(rt2x00dev, INT_SOURCE_CSR, reg);

/*
* Enable tasklets. The beacon related tasklets are
* enabled when the beacon queue is started.
*/
tasklet_enable(&rt2x00dev->txstatus_tasklet);
tasklet_enable(&rt2x00dev->rxdone_tasklet);
tasklet_enable(&rt2x00dev->autowake_tasklet);
}

spin_lock_irqsave(&rt2x00dev->irqmask_lock, flags);
Expand Down Expand Up @@ -472,12 +460,13 @@ static void rt2800pci_toggle_irq(struct rt2x00_dev *rt2x00dev,

if (state == STATE_RADIO_IRQ_OFF) {
/*
* Ensure that all tasklets are finished before
* disabling the interrupts.
* Wait for possibly running tasklets to finish.
*/
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);
tasklet_kill(&rt2x00dev->pretbtt_tasklet);
}
}

Expand Down Expand Up @@ -813,30 +802,33 @@ static void rt2800pci_pretbtt_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
rt2x00lib_pretbtt(rt2x00dev);
rt2800pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_PRE_TBTT);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt2800pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_PRE_TBTT);
}

static void rt2800pci_tbtt_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
rt2x00lib_beacondone(rt2x00dev);
rt2800pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_TBTT);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt2800pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_TBTT);
}

static void rt2800pci_rxdone_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
if (rt2x00pci_rxdone(rt2x00dev))
tasklet_schedule(&rt2x00dev->rxdone_tasklet);
else
else if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt2800pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_RX_DONE);
}

static void rt2800pci_autowake_tasklet(unsigned long data)
{
struct rt2x00_dev *rt2x00dev = (struct rt2x00_dev *)data;
rt2800pci_wakeup(rt2x00dev);
rt2800pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_AUTO_WAKEUP);
if (test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
rt2800pci_enable_interrupt(rt2x00dev, INT_MASK_CSR_AUTO_WAKEUP);
}

static void rt2800pci_txstatus_interrupt(struct rt2x00_dev *rt2x00dev)
Expand Down
1 change: 0 additions & 1 deletion drivers/net/wireless/rt2x00/rt2x00dev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -946,7 +946,6 @@ static int rt2x00lib_probe_hw(struct rt2x00_dev *rt2x00dev)
tasklet_init(&rt2x00dev->taskletname, \
rt2x00dev->ops->lib->taskletname, \
(unsigned long)rt2x00dev); \
tasklet_disable(&rt2x00dev->taskletname); \
}

RT2X00_TASKLET_INIT(txstatus_tasklet);
Expand Down
34 changes: 13 additions & 21 deletions drivers/net/wireless/rt2x00/rt61pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
}

/*
Expand Down Expand Up @@ -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);
}
}

Expand Down Expand Up @@ -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);
}

Expand All @@ -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)
Expand Down

0 comments on commit abc1199

Please sign in to comment.