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From: Saeed Mahameed <saeedm@nvidia.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Leon Romanovsky <leonro@nvidia.com>,
	Eric Dumazet <edumazet@google.com>,
	netdev@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH net-next] net/mlx5: Make ASO poll CQ usable in atomic context
Date: Sat, 24 Sep 2022 10:24:25 -0700	[thread overview]
Message-ID: <20220924172425.bfagbky4h5tbcxf4@fedora> (raw)
In-Reply-To: <d941bb44798b938705ca6944d8ee02c97af7ddd5.1664017836.git.leonro@nvidia.com>

On 24 Sep 14:17, Leon Romanovsky wrote:
>From: Leon Romanovsky <leonro@nvidia.com>
>
>Poll CQ functions shouldn't sleep as they are called in atomic context.
>The following splat appears once the mlx5_aso_poll_cq() is used in such
>flow.
>
> BUG: scheduling while atomic: swapper/17/0/0x00000100

...

> 	/* With newer FW, the wait for the first ASO WQE is more than 2us, put the wait 10ms. */
>-	err = mlx5_aso_poll_cq(aso, true, 10);
>+	expires = jiffies + msecs_to_jiffies(10);
>+	do {
>+		err = mlx5_aso_poll_cq(aso, true);
>+	} while (err && time_is_after_jiffies(expires));
> 	mutex_unlock(&flow_meters->aso_lock);
         ^^^^
busy poll won't work, this mutex is held and can sleep anyway.
Let's discuss internally and solve this by design.


  reply	other threads:[~2022-09-24 17:24 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-24 11:17 [PATCH net-next] net/mlx5: Make ASO poll CQ usable in atomic context Leon Romanovsky
2022-09-24 17:24 ` Saeed Mahameed [this message]
2022-09-24 18:51   ` Leon Romanovsky
2022-09-24 20:11     ` Saeed Mahameed
2022-09-25  6:01       ` Leon Romanovsky

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