From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Dan Williams <dan.j.williams@intel.com>, Lukas Wunner <lukas@wunner.de>
Cc: 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
Subject: Re: [PATCH v5 1/8] dax: alloc_dax() return ERR_PTR(-EOPNOTSUPP) for CONFIG_DAX=n
Date: Tue, 13 Feb 2024 15:07:38 -0500 [thread overview]
Message-ID: <457bde90-5ce7-4c60-9268-e5980ddf6cc0@efficios.com> (raw)
In-Reply-To: <65cbbdfe19172_29b129476@dwillia2-mobl3.amr.corp.intel.com.notmuch>
On 2024-02-13 14:07, Dan Williams wrote:
> Lukas Wunner wrote:
>> On Mon, Feb 12, 2024 at 11:30:54AM -0500, Mathieu Desnoyers wrote:
>>> Change the return value from NULL to PTR_ERR(-EOPNOTSUPP) for
>>> CONFIG_DAX=n to be consistent with the fact that CONFIG_DAX=y
>>> never returns NULL.
>>
>> All the callers of alloc_dax() only check for IS_ERR().
>>
>> Doesn't this result in a change of behavior in all the callers?
>> Previously they'd ignore the NULL return value and continue,
>> now they'll error out.
>>
>> Given that, seems dangerous to add a Fixes tag with a v4.0 commit
>> and thus risk regressing all stable kernels.
>
> Oh, good catch, yes that Fixes tag should be:
>
> 4e4ced93794a dax: Move mandatory ->zero_page_range() check in alloc_dax()
>
> ...as that was the one that updated the alloc_dax() calling convention
> without fixing up the CONFIG_DAX=n case.
>
> This is a pre-requisite for restoring DAX operation on ARM32.
I'll change the Fixes tag in this commit to:
Fixes: 4e4ced93794a ("dax: Move mandatory ->zero_page_range() check in alloc_dax()")
for v6.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
next prev parent reply other threads:[~2024-02-13 20:07 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-12 16:30 [PATCH v5 0/8] Introduce cpu_dcache_is_aliasing() to fix DAX regression Mathieu Desnoyers
2024-02-12 16:30 ` [PATCH v5 1/8] dax: alloc_dax() return ERR_PTR(-EOPNOTSUPP) for CONFIG_DAX=n Mathieu Desnoyers
2024-02-13 6:32 ` Lukas Wunner
2024-02-13 19:07 ` Dan Williams
2024-02-13 20:07 ` Mathieu Desnoyers [this message]
2024-02-12 16:30 ` [PATCH v5 2/8] nvdimm/pmem: Treat alloc_dax() -EOPNOTSUPP failure as non-fatal Mathieu Desnoyers
2024-02-12 16:30 ` [PATCH v5 3/8] dm: " Mathieu Desnoyers
2024-02-12 16:30 ` [PATCH v5 4/8] dcssblk: Handle alloc_dax() -EOPNOTSUPP failure Mathieu Desnoyers
2024-02-13 11:18 ` Heiko Carstens
2024-02-12 16:30 ` [PATCH v5 5/8] virtio: Treat alloc_dax() -EOPNOTSUPP failure as non-fatal Mathieu Desnoyers
2024-02-12 22:04 ` Dan Williams
2024-02-12 22:08 ` Linus Torvalds
2024-02-12 23:02 ` Dan Williams
2024-02-13 6:18 ` Lukas Wunner
2024-02-13 18:56 ` Dan Williams
2024-02-13 20:25 ` Mathieu Desnoyers
2024-02-13 6:25 ` Lukas Wunner
2024-02-13 19:46 ` Mathieu Desnoyers
2024-02-14 6:59 ` Greg Kroah-Hartman
2024-02-12 16:30 ` [PATCH v5 6/8] dax: Check for data cache aliasing at runtime Mathieu Desnoyers
2024-02-12 16:31 ` [PATCH v5 7/8] Introduce cpu_dcache_is_aliasing() across all architectures Mathieu Desnoyers
2024-02-12 16:31 ` [PATCH v5 8/8] dax: Fix incorrect list of data cache aliasing architectures Mathieu Desnoyers
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