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Message-ID: <c0a08e00-e7b5-48ac-a152-3068ab0c9e15@efficios.com>
Date: Tue, 13 Feb 2024 14:46:05 -0500
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Subject: Re: [PATCH v5 5/8] virtio: Treat alloc_dax() -EOPNOTSUPP failure as
 non-fatal
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To: Lukas Wunner <lukas@wunner.de>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>, Arnd Bergmann <arnd@arndb.de>,
 Dave Chinner <david@fromorbit.com>, linux-kernel@vger.kernel.org,
 Andrew Morton <akpm@linux-foundation.org>,
 Linus Torvalds <torvalds@linux-foundation.org>,
 Vishal Verma <vishal.l.verma@intel.com>, Dave Jiang <dave.jiang@intel.com>,
 Matthew Wilcox <willy@infradead.org>, Russell King <linux@armlinux.org.uk>,
 linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org,
 linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
 linux-xfs@vger.kernel.org, dm-devel@lists.linux.dev, nvdimm@lists.linux.dev,
 linux-s390@vger.kernel.org, Alasdair Kergon <agk@redhat.com>,
 Mike Snitzer <snitzer@kernel.org>, Mikulas Patocka <mpatocka@redhat.com>
References: <20240212163101.19614-1-mathieu.desnoyers@efficios.com>
 <20240212163101.19614-6-mathieu.desnoyers@efficios.com>
 <20240213062559.GA27364@wunner.de>
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
In-Reply-To: <20240213062559.GA27364@wunner.de>
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On 2024-02-13 01:25, Lukas Wunner wrote:
> On Mon, Feb 12, 2024 at 11:30:58AM -0500, Mathieu Desnoyers wrote:
>> In preparation for checking whether the architecture has data cache
>> aliasing within alloc_dax(), modify the error handling of virtio
>> virtio_fs_setup_dax() to treat alloc_dax() -EOPNOTSUPP failure as
>> non-fatal.
>>
>> Co-developed-by: Dan Williams <dan.j.williams@intel.com>
>> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>> Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
> 
> That's a v4.0 commit, yet this patch uses DEFINE_FREE() which is
> only available in v6.6 but not any earlier stable kernels.

I asked this question to Greg KH before creating this patch, and his
answer was to implement my fix for master, and stable kernels would take
care of backporting all the required dependencies.

Now if I look at latest 6.1, 5.15, 5.10, 5.4, 4.19 stable kernels,
none seem to have include/linux/cleanup.h today. But I suspect that
sooner or later relevant master branch fixes will require stable
kernels to backport cleanup.h, so why not do it now ?

Thanks,

Mathieu


> 
> So the Fixes tag feels a bit weird.
> 
> Apart from that,
> Reviewed-by: Lukas Wunner <lukas@wunner.de>

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com