Re: please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

[Oleg Nesterov <oleg@redhat.com>]

On 03/21, Linus Torvalds wrote:
>
> On Fri, Mar 21, 2014 at 11:34 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> >
> > Yes, it seems that it actually needs > 30 secs. It spends most of the time
> > (30.13286 seconds) in [..]
>
> So how about taking a completely different approach:

Due to the lack of knowledge I can not comment (or even actually
understand) your suggestion.

But it probably falls into the "right fix" category, iow "THE FIX
FROM MAINTAINERS" the temporary sigprocmask() hack should wait for.

I can't implement this by the same reason. And of course I won't
insist that we need some really stupid (and wrong) solution until
someone who understand makes the initialization asynchronous.


>  - just say that waiting for devices in the module init sequence for
> over 30 seconds is really really wrong.
>
>  - make the damn mptsas driver just register the controller from the
> init sequence, and then do device discovery asynchronously.
>
> The ATA layer does this correctly: it synchronously finds each host,
> but then it does
>
>         /* perform each probe asynchronously */
>         for (i = 0; i < host->n_ports; i++) {
>                 struct ata_port *ap = host->ports[i];
>                 async_schedule(async_port_probe, ap);
>         }
>
> and I really think SCSI drivers should do the same if they have this
> kind of "ports can take forever to probe" behavior.
>
> What would be the equivalent magic to do this for SCSI? Could we just
> make something like scsi_probe_and_add_lun() just always do this, the
> same way ata_host_register() does it?
>
>                    Linus