Re: [PATCH] Revert "scsi: mpt3sas: Fix secure erase premature termination"

[Bart Van Assche <Bart.VanAssche@sandisk.com>]

On Sun, 2017-01-15 at 11:49 -0800, James Bottomley wrote:
> On Sun, 2017-01-15 at 11:41 -0800, Linus Torvalds wrote:
> > On Sun, Jan 15, 2017 at 11:13 AM, James Bottomley
> > <James.Bottomley@hansenpartnership.com> wrote:
> > > 
> > > Can we compromise on "try not to revert a fix ...".
> > 
> > No.
> > 
> > It's about timing, and about how serious the regression is.
> > 
> > For example, if this happened in rc7, I would have reverted
> > immediately. No questions asked.
> > 
> > In this case, the "fix" was was also much less important then the
> > problem it caused. Some specialized pass-through command not
> > working
> > right, vs a machine not even booting? There's just no question
> > what-so-ever.
> > 
> > So the "fix" you claim just wasn't nearly important enough. It was
> > also pretty recent and clearly things had worked for _years_
> > without
> > it.
> > 
> > In fact, I'm still somewhat inclined to revert it, just to have a
> > working rc4 release later today. But I'm hoping maybe Ingo has
> > time 
> > to test things (although I suspect he's already asleep).
> 
> OK, so the patch to revert would actually be
> 
> commit 669f044170d8933c3d66d231b69ea97cb8447338
> Author: Bart Van Assche <bart.vanassche@sandisk.com>
> Date:   Tue Nov 22 16:17:13 2016 -0800
> 
>     scsi: srp_transport: Move queuecommand() wait code to SCSI core
> 
> Because that change in the wait code broke the "fix" in mpt3sas. 
> Before that was applied, it actually worked even though I think it's
> a wrong fix.

Hello James,

I disagree. Even if my patch would be reverted that still wouldn't fix
the severe race condition that was introduced in the mpt3sas driver by
the patch that triggers the lockup during boot. As I explained two
weeks ago (see also https://www.spinics.net/lists/kernel/msg2411413.htm
l), commit 18f6084a989b ("scsi: mpt3sas: Fix secure erase premature
termination") is the one that should be reverted instead of my patch. I
agree with Linus that the offending mpt3sas patch already should have
been reverted.

Bart.