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Date:   Fri, 13 Oct 2023 20:03:40 -0700
From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     Javier Carrasco <javier.carrasco.cruz@gmail.com>
Cc:     John Horan <knasher@gmail.com>,
        Henrik Rydberg <rydberg@bitmath.org>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        syzbot+348331f63b034f89b622@syzkaller.appspotmail.com
Subject: Re: [PATCH v2] Input: bcm5974 - check endpoint type before starting
 traffic
Message-ID: <ZSoFDLv8_CG1SGN6@google.com>
References: <20231007-topic-bcm5974_bulk-v2-1-021131c83efb@gmail.com>
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In-Reply-To: <20231007-topic-bcm5974_bulk-v2-1-021131c83efb@gmail.com>
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Hi Javier,

On Thu, Oct 12, 2023 at 06:51:49PM +0200, Javier Carrasco wrote:
>  
> +static bool bcm5974_ep_is_int_in(struct usb_host_interface *iface, int addr)
> +{
> +	struct usb_endpoint_descriptor *endpoint;
> +	int i;
> +
> +	for (i = 0; i < iface->desc.bNumEndpoints; i++) {
> +		endpoint = &iface->endpoint[i].desc;
> +		if (endpoint->bEndpointAddress == addr) {
> +			if (usb_endpoint_is_int_in(endpoint))
> +				return true;
> +		}
> +	}
> +	return false;
> +}

This essentially reimplements usb_find_endpoint() in a sense, so can we
instead do:

	ep = usb_find_endpoint(iface, addr);
	if (!ep || !usb_endpoint_is_int_in(ep)) {
		dev_err(...);
		return ...;
	}


Also it looks like the handling of button endpoint is interleaved with
the trackpad endpoint, I wonder if it would not be better if we have a
separate "if (cfg->tp_type == TYPE1)" where we would do the check,
allocate URB, and did all the rest of set up for button transfers.

Thanks.

-- 
Dmitry