From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Arnd Bergmann <arnd@arndb.de>,
Dave Chinner <david@fromorbit.com>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@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>
Subject: Re: [PATCH v5 5/8] virtio: Treat alloc_dax() -EOPNOTSUPP failure as non-fatal
Date: Mon, 12 Feb 2024 14:08:20 -0800 [thread overview]
Message-ID: <CAHk-=wiqaENZFBiAihFxdLr2E+kSM4P64M3uPzwT4-K9NiVSmw@mail.gmail.com> (raw)
In-Reply-To: <65ca95d086dfd_d2d429470@dwillia2-xfh.jf.intel.com.notmuch>
On Mon, 12 Feb 2024 at 14:04, Dan Williams <dan.j.williams@intel.com> wrote:
>
> This works because the internals of virtio_fs_cleanup_dax(), "kill_dax()
> and put_dax()", know how to handle a NULL @dax_dev. It is still early
> days with the "cleanup" helpers, but I wonder if anyone else cares that
> the DEFINE_FREE() above does not check for NULL?
Well, the main reason for DEFINE_FREE() to check for NULL is not
correctness, but code generation. See the comment about kfree() in
<linux/cleanup.h>:
* NOTE: the DEFINE_FREE()'s @free expression includes a NULL test even though
* kfree() is fine to be called with a NULL value. This is on purpose. This way
* the compiler sees the end of our alloc_obj() function as [...]
with the full explanation there.
Now, whether the code wants to actually use the cleanup() helpers for
a single use-case is debatable.
But yes, if it does, I suspect it should use !IS_ERR_OR_NULL(ptr).
Linus
next prev parent reply other threads:[~2024-02-12 22:08 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAHk-=wiqaENZFBiAihFxdLr2E+kSM4P64M3uPzwT4-K9NiVSmw@mail.gmail.com' \
--to=torvalds@linux-foundation.org \
--cc=agk@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=dan.j.williams@intel.com \
--cc=dave.jiang@intel.com \
--cc=david@fromorbit.com \
--cc=dm-devel@lists.linux.dev \
--cc=linux-arch@vger.kernel.org \
--cc=linux-cxl@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=mathieu.desnoyers@efficios.com \
--cc=mpatocka@redhat.com \
--cc=nvdimm@lists.linux.dev \
--cc=snitzer@kernel.org \
--cc=vishal.l.verma@intel.com \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).