Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 4 Aug 2021 17:33:08 +0200
From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Daniel Wagner <wagi@monom.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-rt-users@vger.kernel.org,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [ANNOUNCE] v5.14-rc4-rt4
Message-ID: <20210804153308.oasahcxjmcw7vivo@linutronix.de>
References: <20210802162750.santic4y6lzcet5c@linutronix.de>
 <20210804082418.fbibprcwtzyt5qax@beryllium.lan>
 <20210804104340.fhdjwn3hruymu3ml@linutronix.de>
 <20210804104803.4nwxi74sa2vwiujd@linutronix.de>
 <20210804110057.chsvt7l5xpw7bo5r@linutronix.de>
 <20210804131731.GG8057@worktop.programming.kicks-ass.net>
 <4f549344-1040-c677-6a6a-53e243c5f364@kernel.dk>
 <feebf183-2e33-36b5-4538-62a40b2a58b6@kernel.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <feebf183-2e33-36b5-4538-62a40b2a58b6@kernel.dk>
Precedence: bulk

On 2021-08-04 08:23:55 [-0600], Jens Axboe wrote:
> Totally untested, but I think the principle is sound. I'll run it through
> some testing.

This is needed:

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 1192ee2abd982..77ec6896edaa5 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -428,9 +428,9 @@ static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
 	}
 
 	if (stall_hash != -1U) {
-		raw_spin_unlock(&wqe->lock);
+		raw_spin_unlock_irq(&wqe->lock);
 		io_wait_on_hash(wqe, stall_hash);
-		raw_spin_lock(&wqe->lock);
+		raw_spin_lock_irq(&wqe->lock);
 	}
 
 	return NULL;


otherwise the spinlock_t lock in io_wait_on_hash() is acquired with
disabled interrupts which is a no-no on -RT.
With that it all looks good as far as I can tell.
Thank you.

Sebastian