Messages in this thread | | | Date | Tue, 21 Jun 2005 11:58:22 +0200 | From | Johannes Stezenbach <> | Subject | Re: [patch 2/4] cdrom/aztcd: remove sleep_on() usage |
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domen@coderock.org wrote: > From: Nishanth Aravamudan <nacc@us.ibm.com> > > > > Directly use wait-queues instead of the deprecated sleep_on(). > This required adding a local waitqueue. Patch is compile-tested.
IMHO this patch doesn't improve anything, it just makes the code harder to read. sleep_on() is deprecated because there's an inherent race between sleep_on() and wake_up(). To address this you need to add a condition variable (e.g. AztStenLow) and convert the code to use wait_event(). The timer trick used here makes it pretty hard to hit the race, but with a preemptible kernel one could be preempted between the SET_TIMER() and the sleep_on().
Johannes
> Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> > Signed-off-by: Domen Puncer <domen@coderock.org> > --- > aztcd.c | 6 +++++- > 1 files changed, 5 insertions(+), 1 deletion(-) > > Index: quilt/drivers/cdrom/aztcd.c > =================================================================== > --- quilt.orig/drivers/cdrom/aztcd.c > +++ quilt/drivers/cdrom/aztcd.c > @@ -179,6 +179,7 @@ > #include <linux/ioport.h> > #include <linux/string.h> > #include <linux/major.h> > +#include <linux/wait.h> > > #include <linux/init.h> > > @@ -429,9 +430,12 @@ static void dten_low(void) > #define STEN_LOW_WAIT statusAzt() > static void statusAzt(void) > { > + DEFINE_WAIT(wait); > AztTimeout = AZT_STATUS_DELAY; > SET_TIMER(aztStatTimer, HZ / 100); > - sleep_on(&azt_waitq); > + prepare_to_wait(&azt_waitq, &wait, TASK_UNINTERRUPTIBLE); > + schedule(); > + finish_wait(&azt_waitq, &wait); > if (AztTimeout <= 0) > printk("aztcd: Error Wait STEN_LOW_WAIT command:%x\n", > aztCmd); > - 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/
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