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: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-By: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/wan/cosa.c b/drivers/net/wan/cosa.c
index 83c39e2..88d121d 100644 (file)
--- a/drivers/net/wan/cosa.c
+++ b/drivers/net/wan/cosa.c
@@ -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);