From: Mike Snitzer <snitzer@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Pankaj Gupta <pagupta@redhat.com>,
device-mapper development <dm-devel@redhat.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Alasdair Kergon <agk@redhat.com>,
jencce.kernel@gmail.com
Subject: Re: dm: fix dax_dev NULL dereference
Date: Tue, 30 Jul 2019 18:01:02 -0400 [thread overview]
Message-ID: <20190730220102.GA15604@redhat.com> (raw)
In-Reply-To: <CAPcyv4i10K3QdSwa3EF9t8pS-QrB9YcBEMy49N1PnYQzCkBJCw@mail.gmail.com>
On Tue, Jul 30 2019 at 5:38pm -0400,
Dan Williams <dan.j.williams@intel.com> wrote:
> On Tue, Jul 30, 2019 at 12:07 PM Mike Snitzer <snitzer@redhat.com> wrote:
> >
> > I staged the fix (which I tweaked) here:
> > https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-5.3&id=95b9ebb78c4c733f8912a195fbd0bc19960e726e
>
> Thanks for picking this up Mike, but I'd prefer to just teach
> dax_synchronous() to return false if the passed in dax_dev is NULL.
> Thoughts?
I considered that too but I moved away from it because I'm so used to
the various block interfaces requiring the caller pass a non-NULL
pointer (e.g. request_queue):
$ grep -ri return drivers/md/dm-table.c | grep \&\&
drivers/md/dm-table.c: return dev->dax_dev && dax_synchronous(dev->dax_dev);
drivers/md/dm-table.c: return q && blk_queue_zoned_model(q) == *zoned_model;
drivers/md/dm-table.c: return q && blk_queue_zone_sectors(q) == *zone_sectors;
drivers/md/dm-table.c: return q && (q->queue_flags & flush);
drivers/md/dm-table.c: return q && blk_queue_nonrot(q);
drivers/md/dm-table.c: return q && !blk_queue_add_random(q);
drivers/md/dm-table.c: return q && !q->limits.max_write_same_sectors;
drivers/md/dm-table.c: return q && !q->limits.max_write_zeroes_sectors;
drivers/md/dm-table.c: return q && !blk_queue_discard(q);
drivers/md/dm-table.c: return q && !blk_queue_secure_erase(q);
drivers/md/dm-table.c: return q && bdi_cap_stable_pages_required(q->backing_dev_info);
I'm fine with however you'd like to skin this cat though.
Just let me know and I'll keep/drop this patch accordingly.
Thanks,
Mike
next prev parent reply other threads:[~2019-07-30 22:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 11:37 [PATCH] dm: fix dax_dev NULL dereference Pankaj Gupta
2019-07-30 11:38 ` Pankaj Gupta
2019-07-30 19:07 ` Mike Snitzer
2019-07-30 21:38 ` Dan Williams
2019-07-30 22:01 ` Mike Snitzer [this message]
2019-07-30 22:15 ` Dan Williams
2019-07-31 3:50 ` Pankaj Gupta
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