From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Willy Tarreau <w@1wt.eu>
Subject: Re: [PATCH] auxdisplay: Remove in_interrupt() usage.
Date: Mon, 8 Feb 2021 21:41:36 +0100 [thread overview]
Message-ID: <20210208204136.sv4omzms3nadse6e@linutronix.de> (raw)
In-Reply-To: <CANiq72kq_d=5TvdhndP9zkyTD1pHF6WQb+qs01D68DEQH6jVjQ@mail.gmail.com>
On 2021-02-08 21:14:54 [+0100], Miguel Ojeda wrote:
> On Mon, Feb 8, 2021 at 8:07 PM Sebastian Andrzej Siewior
> <bigeasy@linutronix.de> wrote:
> >
> > Yes.
>
> In what way?
It hurts to keep in_interrupt() because it is desired to have it removed
from drivers. The problem is that pattern is often copied and people
sometimes get it wrong. For instance, the code here invoked schedule()
based on in_interrupt(). It did not check whether or not the interrupts
are disabled which is also important. It may work now, it can break in
future if an unrelated change is made. An example is commit
c2d0f1a65ab9f ("scsi: libsas: Introduce a _gfp() variant of event notifiers")
https://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git/commit/?id=c2d0f1a65ab9f
in_interrupt() is often used in old code that was written before
might_sleep() and lockdep was introduced.
> > No. If you know the context, pass it along like this is done for
> > kmalloc() for instance.
>
> What do you mean?
What I meant was GFP_KERNEL for context which can sleep vs GFP_ATOMIC for
context which must not sleep. The commit above also eliminates the
in_interrupt() usage within the driver (in multiple steps).
> Cheers,
> Miguel
Sebastian
next prev parent reply other threads:[~2021-02-08 21:32 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-08 17:58 [PATCH] auxdisplay: Remove in_interrupt() usage Sebastian Andrzej Siewior
2021-02-08 18:38 ` Miguel Ojeda
2021-02-08 19:07 ` Sebastian Andrzej Siewior
2021-02-08 20:14 ` Miguel Ojeda
2021-02-08 20:41 ` Sebastian Andrzej Siewior [this message]
2021-02-08 22:26 ` Miguel Ojeda
2021-02-09 9:01 ` Sebastian Andrzej Siewior
2021-02-10 21:46 ` Miguel Ojeda
2021-02-13 16:50 ` [PATCH v3] " Sebastian Andrzej Siewior
2021-02-16 9:32 ` Miguel Ojeda
2021-02-16 10:28 ` Sebastian Andrzej Siewior
2021-02-16 12:42 ` Miguel Ojeda
2021-02-16 18:26 ` Sebastian Andrzej Siewior
2021-02-16 18:27 ` [PATCH v4] " Sebastian Andrzej Siewior
2021-02-16 20:21 ` [PATCH v3] " Miguel Ojeda
2021-03-10 17:51 ` Sebastian Andrzej Siewior
2021-03-10 18:04 ` Miguel Ojeda
2021-02-08 19:37 ` [PATCH v2] " Sebastian Andrzej Siewior
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=20210208204136.sv4omzms3nadse6e@linutronix.de \
--to=bigeasy@linutronix.de \
--cc=geert@linux-m68k.org \
--cc=linux-kernel@vger.kernel.org \
--cc=miguel.ojeda.sandonis@gmail.com \
--cc=tglx@linutronix.de \
--cc=w@1wt.eu \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.