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Date: Thu, 28 May 2026 04:33:16 +0000
From: Tzung-Bi Shih <tzungbi@kernel.org>
To: Benson Leung <bleung@chromium.org>, Jason Gunthorpe <jgg@nvidia.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: chrome-platform@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 4/4] platform/chrome: cros_ec_chardev: Introduce rwsem
 for protecting ec_dev
Message-ID: <ahfFjKooNDyOP6Zm@google.com>
References: <20260525052654.4076429-1-tzungbi@kernel.org>
 <20260525052654.4076429-5-tzungbi@kernel.org>
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In-Reply-To: <20260525052654.4076429-5-tzungbi@kernel.org>

On Mon, May 25, 2026 at 05:26:54AM +0000, Tzung-Bi Shih wrote:
> diff --git a/drivers/platform/chrome/cros_ec_chardev.c b/drivers/platform/chrome/cros_ec_chardev.c
> index 7e046fc56998..25ad409523b8 100644
...
> @@ -219,6 +229,10 @@ static __poll_t cros_ec_chardev_poll(struct file *filp, poll_table *wait)
>  {
>  	struct chardev_priv *priv = filp->private_data;
>  
> +	guard(rwsem_read)(&priv->pdata->ec_dev_sem);
> +	if (!priv->pdata->ec_dev)
> +		return -ENODEV;

FWIW: I realized -ENODEV isn't a correct return value for poll().
Return EPOLLHUP instead, and squash into the patch.