From: Arnd Bergmann <arnd@arndb.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Sven Eckelmann <sven@narfation.org>,
Arnd Bergmann <arnd@arndb.de>,
b.a.t.m.a.n@lists.open-mesh.org,
linux-arch <linux-arch@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] asm-generic: avoid sparse {get,put}_unaligned warning
Date: Mon, 26 Jul 2021 14:57:31 +0200 [thread overview]
Message-ID: <CAK8P3a2MVQMFFBUzudy+yrcp4Md8mm=NcvX7YzGVz4C8W61sgQ@mail.gmail.com> (raw)
In-Reply-To: <YPxHYW/HPI/LLMXx@zeniv-ca.linux.org.uk>
On Sat, Jul 24, 2021 at 7:01 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> On Sat, Jul 24, 2021 at 06:24:29PM +0200, Sven Eckelmann wrote:
>
> > The special attribute force must be used in such statements when the cast
> > is known to be safe to avoid these warnings.
I can see why this would warn, but I'm having trouble reproducing the
warning on linux-next.
> How about container_of(ptr, typeof(*__pptr), x) instead of a cast?
> Would be easier to follow...
If both work equally well, I'd prefer Sven's patch since that only
expands 'type'
once, while container_of() expands it three more times. This may not make
much of a difference, but I've seen a number of cases where nested macros
can explode the preprocessed code size enough to slow down kernel compilation
over all, and it's quite possible to have get_unaligned()/put_unaligned in
the middle of that, with a complex expression passed into that.
Arnd
next prev parent reply other threads:[~2021-07-26 12:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-24 16:24 [PATCH] asm-generic: avoid sparse {get,put}_unaligned warning Sven Eckelmann
2021-07-24 17:01 ` Al Viro
2021-07-26 12:57 ` Arnd Bergmann [this message]
2021-07-26 15:04 ` Sven Eckelmann
2021-07-26 16:22 ` Arnd Bergmann
2021-07-27 8:44 ` David Laight
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='CAK8P3a2MVQMFFBUzudy+yrcp4Md8mm=NcvX7YzGVz4C8W61sgQ@mail.gmail.com' \
--to=arnd@arndb.de \
--cc=b.a.t.m.a.n@lists.open-mesh.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=sven@narfation.org \
--cc=viro@zeniv.linux.org.uk \
/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 NNTP newsgroup(s).