Messages in this thread | | | Date | Mon, 10 Jan 2005 09:39:45 -0800 | From | Nishanth Aravamudan <> | Subject | Re: [UPDATE PATCH] ieee1394/sbp2: use ssleep() instead of schedule_timeout() |
| |
On Sun, Jan 09, 2005 at 10:01:21AM +0100, Stefan Richter wrote: > Nishanth Aravamudan wrote: > >Description: Use ssleep() instead of schedule_timeout() to guarantee > >the task > >delays as expected. The existing code should not really need to run in > >TASK_INTERRUPTIBLE, as there is no check for signals (or even an > >early return > >value whatsoever). ssleep() takes care of these issues. > > >--- 2.6.10-v/drivers/ieee1394/sbp2.c 2004-12-24 13:34:00.000000000 > >-0800 > >+++ 2.6.10/drivers/ieee1394/sbp2.c 2005-01-05 14:23:05.000000000 -0800 > >@@ -902,8 +902,7 @@ alloc_fail: > > * connected to the sbp2 device being removed. That host would > > * have a certain amount of time to relogin before the sbp2 device > > * allows someone else to login instead. One second makes sense. */ > >- set_current_state(TASK_INTERRUPTIBLE); > >- schedule_timeout(HZ); > >+ ssleep(1); > > Maybe the current code is _deliberately_ accepting interruption by > signals but trying to complete sbp2_probe() anyway. However it seems > more plausible to me to abort the device probe, for example like this: > if (msleep_interruptible(1000)) { > sbp2_remove_device(scsi_id); > return -EINTR; > }
You might be right, but I'd like to get Ben's input on this, as I honeslty am unsure. To be fair, I am trying to audit all usage of schedule_timeout() and the semantic interpretation (to me) of using TASK_INTERRUPTIBLE is that you wish to sleep a certain amount of time, but also are prepared for an early return on either signals or wait-queue events. msleep_interruptible() cleanly removes this second issue, but still requires the caller to respond appropriately if there is a return value. Hence, I like your change. I think it makes the most sense. Since I didn't/don't know how the device works, I was not able to make the change myself. Thanks for your input!
> Anyway, signal handling does not appear to be critical there.
Just out of curiousity, doesn't that run the risk, though, of signal_pending(current) being true for quite a bit of time following the timeout?
Thanks, Nish - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |