In place kexec

[Randy Dunlap]

On Thu, 29 Jul 2010 12:51:09 -0700 Eric W. Biederman wrote:

> Vivek Goyal <vgoyal at redhat.com> writes:
> 
> > On Thu, Jul 29, 2010 at 11:29:12AM -0700, H. Peter Anvin wrote:
> >> On 07/29/2010 11:06 AM, Eric W. Biederman wrote:
> >> > 
> >> > Thinking about this I am a bit surprised that you would find
> >> > DMA left on from a disk driver.  Historically disks have been
> >> > pretty good about shutting off in this scenario.
> >> > 
> >> > Added to that typically we unmount all filesystems.
> >> > 
> >> > Calling rmmod on the driver before the final kexec --exec
> >> > could be interesting, and drivers much more reliably implement
> >> > .remove than .shutdown.
> >> > 
> >> > Network drivers are more likely to be a problem, but we should be
> >> > downing all of the network interfaces before something happens.
> >> > 
> >> > All of which is to say kexec-in-place has generally been a lot
> >> > less hassle, because it is so similar to the normal case.
> >> > 
> >> 
> >> In particular, the supposed corruption comes from the "firmware logging"
> >> feature in the qla2xxx driver.  I'd really like to understand if this is
> >> a kexec problem or a qla2xxx problem.
> >> 	
> >
> > kernel_kexec()
> >    kernel_restart_prepare()
> > 	device_shutdown()
> >
> > I would suspect it to be a qla2xxx driver problem that it did not shut
> > down the device properly.
> 
> And device_shutdown calls every drivers .shutdown method.
> 
> Things like this are always a driver problem.


so is there a default .shutdown method for drivers that do not specify one?

like the qla2xxx driver does not.

---
~Randy
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