| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Wed, 4 Apr 2018 21:42:28 +0200 |
| Subject: [PATCH] ide: Handle irq disabling consistently |
| |
| ide_timer_expiry() disables interrupt at function entry when acquiring |
| hwif->lock. Before disabling the device interrupt it unlocks hwif->lock, |
| but interrupts stay disabled. After the call to disable_irq() interrupts |
| are disabled again, which is a pointless exercise. |
| |
| After the device irq handler has been invoked with interrupts disabled, |
| hwif->lock is acquired again with spin_lock_irq() because the device irq |
| handler might have reenabled interrupts. This is not documented and |
| confusing for the casual reader. |
| |
| Remove the redundant local_irq_disable() and add a comment which explains |
| why hwif->lock has to be reacquired with spin_lock_irq(). |
| |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| drivers/ide/ide-io.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/ide/ide-io.c |
| +++ b/drivers/ide/ide-io.c |
| @@ -659,8 +659,7 @@ void ide_timer_expiry (struct timer_list |
| spin_unlock(&hwif->lock); |
| /* disable_irq_nosync ?? */ |
| disable_irq(hwif->irq); |
| - /* local CPU only, as if we were handling an interrupt */ |
| - local_irq_disable(); |
| + |
| if (hwif->polling) { |
| startstop = handler(drive); |
| } else if (drive_is_ready(drive)) { |
| @@ -679,6 +678,7 @@ void ide_timer_expiry (struct timer_list |
| startstop = ide_error(drive, "irq timeout", |
| hwif->tp_ops->read_status(hwif)); |
| } |
| + /* Disable interrupts again, `handler' might have enabled it */ |
| spin_lock_irq(&hwif->lock); |
| enable_irq(hwif->irq); |
| if (startstop == ide_stopped && hwif->polling == 0) { |
