Linux-rt-users Archive on lore.kernel.org
 help / color / Atom feed
From: Andrew Halaney <ahalaney@redhat.com>
To: bigeasy@linutronix.de
Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
	Chunyu Hu <chuhu@redhat.com>
Subject: Re: [RT PATCH] locking/rwsem-rt: Remove might_sleep() in __up_read()
Date: Mon, 26 Apr 2021 11:42:29 -0500
Message-ID: <20210426164229.mbrsrjpmmhp7ehna@halaneylaptop> (raw)
In-Reply-To: <20210406221952.50399-1-ahalaney@redhat.com>

On Tue, Apr 06, 2021 at 05:19:52PM -0500, Andrew Halaney wrote:
> There's no chance of sleeping here, the reader is giving up the
> lock and possibly waking up the writer who is waiting on it.
> 
> Reported-by: Chunyu Hu <chuhu@redhat.com>
> Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
> ---
> Hello,
> 
> I ran into a warning caused by this, and I think the warning is
> incorrect. Please let me know if I'm wrong!
> I'm working off of linux-5.12.y-rt, but this applies cleanly to older
> stable branches as well.
> 
> Thanks,
> Andrew
> 
>  kernel/locking/rwsem-rt.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/kernel/locking/rwsem-rt.c b/kernel/locking/rwsem-rt.c
> index 274172d5bb3a..b61edc4dcb73 100644
> --- a/kernel/locking/rwsem-rt.c
> +++ b/kernel/locking/rwsem-rt.c
> @@ -198,7 +198,6 @@ void __up_read(struct rw_semaphore *sem)
>  	if (!atomic_dec_and_test(&sem->readers))
>  		return;
>  
> -	might_sleep();
>  	raw_spin_lock_irq(&m->wait_lock);
>  	/*
>  	 * Wake the writer, i.e. the rtmutex owner. It might release the
> -- 
> 2.30.2
> 

Just a gentle follow up, any feedback?

Thanks,
Andrew


  reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-06 22:19 Andrew Halaney
2021-04-26 16:42 ` Andrew Halaney [this message]
2021-04-26 18:16   ` Thomas Gleixner

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=20210426164229.mbrsrjpmmhp7ehna@halaneylaptop \
    --to=ahalaney@redhat.com \
    --cc=bigeasy@linutronix.de \
    --cc=chuhu@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rt-users@vger.kernel.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

Linux-rt-users Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rt-users/0 linux-rt-users/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rt-users linux-rt-users/ https://lore.kernel.org/linux-rt-users \
		linux-rt-users@vger.kernel.org
	public-inbox-index linux-rt-users

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rt-users


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git