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SubjectRe: [PATCH 2/2] cciss: Fix SCSI device reset handler
On Tue, Jun 02 2009, Andrew Morton wrote:
> On Tue, 2 Jun 2009 14:50:11 +0200
> Jens Axboe <jens.axboe@oracle.com> wrote:
>
> > On Fri, May 29 2009, Andrew Morton wrote:
> > > On Wed, 27 May 2009 15:30:07 -0500
> > > scameron@beardog.cca.cpqcorp.net wrote:
> > >
> > > > +static int wait_for_device_to_become_ready(ctlr_info_t *h,
> > > > + unsigned char lunaddr[])
> > > > +{
> > > > + int rc;
> > > > + int count = 0;
> > > > + int waittime = HZ;
> > > > + CommandList_struct *c;
> > > > +
> > > > + c = cmd_alloc(h, 1);
> > > > + if (!c) {
> > > > + printk(KERN_WARNING "cciss%d: out of memory in "
> > > > + "wait_for_device_to_become_ready.\n", h->ctlr);
> > > > + return IO_ERROR;
> > > > + }
> > > > +
> > > > + /* Send test unit ready until device ready, or give up. */
> > > > + while (count < 20) {
> > > > +
> > > > + /* Wait for a bit. do this first, because if we send
> > > > + * the TUR right away, the reset will just abort it.
> > > > + */
> > > > + set_current_state(TASK_INTERRUPTIBLE);
> > > > + schedule_timeout(waittime);
> > >
> > > That's schedule_timeout_interruptible().
> > >
> > > The problem with interruptible sleeps of this nature is that they are
> > > no-ops if the calling process happens to have signal_pending(). I
> > > suspect that this condition will break your driver.
> > >
> > > If so, switching to schedule_timeout_uninterruptible() will unbreak it.
> >
> > I added Stephens patch and your fixup.
>
> My cciss-fix-scsi-device-reset-handler-fix.patch was a simple cleanup -
> it uses schedule_timeout_interruptible().
>
> I believe that this should be changed to
> schedule_timeout_uninterruptible() for the above reasons, but the cciss
> guys fell asleep on me.

It's an improvement, none the less. And I bet it should just be
uninterruptible sleep, unless it has a good reason to accept signals.
Mike? Stephen?

--
Jens Axboe



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