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Commit 2c45015a authored by Fabian Frederick's avatar Fabian Frederick Committed by David S. Miller
Browse files

wan: cosa: replace current->state by set_current_state() 



Use helper functions to access current->state.
Direct assignments are prone to races and therefore buggy.

current->state = TASK_RUNNING is replaced by __set_current_state()

Thanks to Peter Zijlstra for the exact definition of the problem.

Suggested-By: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarFabian Frederick <fabf@skynet.be>
Acked-By: default avatarJan "Yenya" Kasprzak <kas@fi.muni.cz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 50462ce0

drivers/net/wan/cosa.c

+6 −6
Original line number Diff line number Diff line
@@ -806,21 +806,21 @@ static ssize_t cosa_read(struct file *file, 
	spin_lock_irqsave(&cosa->lock, flags);

	add_wait_queue(&chan->rxwaitq, &wait);

	while (!chan->rx_status) {

		current->state = TASK_INTERRUPTIBLE;

		set_current_state(TASK_INTERRUPTIBLE);

		spin_unlock_irqrestore(&cosa->lock, flags);

		schedule();

		spin_lock_irqsave(&cosa->lock, flags);

		if (signal_pending(current) && chan->rx_status == 0) {

			chan->rx_status = 1;

			remove_wait_queue(&chan->rxwaitq, &wait);

			current->state = TASK_RUNNING;

			__set_current_state(TASK_RUNNING);

			spin_unlock_irqrestore(&cosa->lock, flags);

			mutex_unlock(&chan->rlock);

			return -ERESTARTSYS;

		}

	}

	remove_wait_queue(&chan->rxwaitq, &wait);

	current->state = TASK_RUNNING;

	__set_current_state(TASK_RUNNING);

	kbuf = chan->rxdata;

	count = chan->rxsize;

	spin_unlock_irqrestore(&cosa->lock, flags);
@@ -890,14 +890,14 @@ static ssize_t cosa_write(struct file *file, 
	spin_lock_irqsave(&cosa->lock, flags);

	add_wait_queue(&chan->txwaitq, &wait);

	while (!chan->tx_status) {

		current->state = TASK_INTERRUPTIBLE;

		set_current_state(TASK_INTERRUPTIBLE);

		spin_unlock_irqrestore(&cosa->lock, flags);

		schedule();

		spin_lock_irqsave(&cosa->lock, flags);

		if (signal_pending(current) && chan->tx_status == 0) {

			chan->tx_status = 1;

			remove_wait_queue(&chan->txwaitq, &wait);

			current->state = TASK_RUNNING;

			__set_current_state(TASK_RUNNING);

			chan->tx_status = 1;

			spin_unlock_irqrestore(&cosa->lock, flags);

			up(&chan->wsem);
@@ -905,7 +905,7 @@ static ssize_t cosa_write(struct file *file, 
		}

	}

	remove_wait_queue(&chan->txwaitq, &wait);

	current->state = TASK_RUNNING;

	__set_current_state(TASK_RUNNING);

	up(&chan->wsem);

	spin_unlock_irqrestore(&cosa->lock, flags);

	kfree(kbuf);