Re: [PATCH] block: Free queue resources at blk_release_queue()

From: James Bottomley
Date: Wed Sep 28 2011 - 10:11:18 EST


On Wed, 2011-09-28 at 08:08 -0600, Jens Axboe wrote:
> On 2011-09-27 22:10, James Bottomley wrote:
> > On Tue, 2011-09-27 at 18:59 -0700, Linus Torvalds wrote:
> >> On Tue, Sep 27, 2011 at 6:15 PM, Jens Axboe <axboe@xxxxxxxxx> wrote:
> >>>>
> >>>> But if you forward the actual patch to me (the one I see on lkml seems
> >>>> to be broken and doesn't compile cleanly because it's assiging a
> >>>> structure to a pointer), I'll try it out anyway.
> >>>
> >>> Thanks, that would be great. It's inlined below.
> >>
> >> Well, I did several USB eject events, and nothing bad happened.
> >>
> >> But as mentioned, I don't think that means much. Have you tried this
> >> with slub debugging and poisoning? It might be worth some extra
> >> testing that way.
> >
> > I've been testing a simpler version:
> >
> > http://marc.info/?l=linux-kernel&m=131300594629839
> >
> > For a long time now with great success. The only difference is the
> > locking cleanup, but SCSI doesn't need that since it doesn't supply its
> > own lock, so I've been voting for this as the final fix for a while now.
>
> The locking cleanup looks good, though, for devices that do use the
> embedded lock.

Exactly ... it's the missing piece; without it my patch is really only
addressing SCSI.

> But functionally they should be the same for SCSI, so if
> you had great success with it, then that's a good data point.

Right, I've run it through the memory debugger and USB ejection testing
(with ext2, which seems to be the fs that triggers this problem the
most).

James



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