workqueues and schedule()

[Davide Rossetti]

<environment>
I'm authoring a (GPL) driver for a custom 3D network card.
</environment>

on calling some polling functions from within a workqueue, I'm getting 
lockups... sysrq-p got it clear I have a workqueue thread down into 
schedule_timeout().
is considered polite to call schedule ? is in_softirq() capable to diff 
workqueue/normal case ?

static int __apedev_hdrring_poll_end_dma(ApeDev* apedev, struct 
ApeHdrRing* ring)
{
   int ret = 0;
   int counter;

   APE_BUG_ON(0 == ring);
   APE_BUG_ON(0 == apedev);   
  
   // here I poll on the rwbuf memory content till dma is done
   ndelay(5*HZPCI);
   APEDEV_COUNTER_INC(apedev, hdrring_poll_ndelay_cnt);
   counter = 0;
   while(1) {
       if(0 != __apedev_hdrring_check_magic(apedev, ring))
           break;

       counter++;
       ndelay(20*HZPCI);
       if(0 == counter % 512) {
           APEDEV_COUNTER_INC(apedev, hdrring_poll_ndelay_cnt);
           ndelay(50*HZPCI);
       }
       if(counter==2048*16) { // time past is 2048*16/512*50HZPCI
           PDEBUG("counter overflows 2048*16, delaying 1 jiffy\n");

           set_current_state(TASK_UNINTERRUPTIBLE);
           schedule_timeout(MAX(HZ/100,1));            //<----

           counter = 0;
           APEDEV_COUNTER_INC(apedev, hdrring_poll_resched_cnt);
       }
       if(signal_pending(current)) {
           PERROR("GOT SIGNAL!!!\n");
           //apedev_v3_dump_regs(apedev);
           ret = -EINTR;
           goto err;
       }
   }
err:
   return ret;
}

// fast path
static inline int apedev_hdrring_poll_end_dma(ApeDev* apedev, struct 
ApeHdrRing* ring)
{
   int ret = 0;
   int retcode;

   APE_BUG_ON(0 == ring);
   APE_BUG_ON(0 == apedev);   
  
   retcode = __apedev_hdrring_check_magic(apedev, ring);
   if(retcode < 0) {
       PERROR("error in check_magic\n");
       ret = retcode;
       // exit with true...
   } else if(ret==0) {
       ret = __apedev_hdrring_poll_end_dma(apedev, ring);
       PDEBUG("ret=%d\n", ret);
   }
   return ret;
}


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/