Messages in this thread | | | Date | Thu, 21 Jan 2010 11:53:14 +0100 | From | Frederic Weisbecker <> | Subject | Re: Lots of bugs with current->state = TASK_*INTERRUPTIBLE |
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On Thu, Jan 21, 2010 at 11:47:41AM +0100, Julia Lawall wrote: > What about something like the following (drivers/macintosh/adb.c): > > add_wait_queue(&state->wait_queue, &wait); > current->state = TASK_INTERRUPTIBLE; > > for (;;) { > req = state->completed; > if (req != NULL) > state->completed = req->next; > else if (atomic_read(&state->n_pending) == 0) > ret = -EIO; > if (req != NULL || ret != 0) > break; > > if (file->f_flags & O_NONBLOCK) { > ret = -EAGAIN; > break; > } > if (signal_pending(current)) { > ret = -ERESTARTSYS; > break; > } > spin_unlock_irqrestore(&state->lock, flags); > schedule(); > spin_lock_irqsave(&state->lock, flags); > } > > current->state = TASK_RUNNING; > remove_wait_queue(&state->wait_queue, &wait); > > There is a call to schedule eventually after the first current->state > assignment, but it is not right after.
Looks fine as spin_unlock includes a memory barrier, IIRC.
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