linux-kernel - Re: [PATCH] HID: usbhid: Convert timers to use timer

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Message-ID: <20171006074944.GC865@mail.corp.redhat.com>
Date:   Fri, 6 Oct 2017 09:49:44 +0200
From:   Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:     Kees Cook <keescook@...omium.org>
Cc:     linux-kernel@...r.kernel.org, Jiri Kosina <jikos@...nel.org>,
        linux-input@...r.kernel.org, linux-usb@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] HID: usbhid: Convert timers to use timer_setup()

On Oct 04 2017 or thereabouts, Kees Cook wrote:
> In preparation for unconditionally passing the struct timer_list pointer to
> all timer callbacks, switch to using the new timer_setup() and from_timer()
> to pass the timer pointer explicitly. Adds pointer back to hid_device for
> multitouch.
> 
> Cc: Jiri Kosina <jikos@...nel.org>
> Cc: Benjamin Tissoires <benjamin.tissoires@...hat.com>
> Cc: linux-input@...r.kernel.org
> Cc: linux-usb@...r.kernel.org
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Signed-off-by: Kees Cook <keescook@...omium.org>
> ---
> This requires commit 686fef928bba ("timer: Prepare to change timer
> callback argument type") in v4.14-rc3, but should be otherwise
> stand-alone.

Looks good to me:
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>

Selfish request: Jiri can you add the dependency about 686fef928bba in
the commit message too? I am just preparing in case I need to backport
this in RHEL, and having the dep explicitly mentioned would save me a
little bit of extra time :)
(if not, no worries)

Cheers,
Benjamin

> ---
>  drivers/hid/hid-multitouch.c  | 10 ++++++----
>  drivers/hid/usbhid/hid-core.c |  8 ++++----
>  2 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 440b999304a5..b0e3e2614b18 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -112,6 +112,7 @@ struct mt_device {
>  	struct mt_slot curdata;	/* placeholder of incoming data */
>  	struct mt_class mtclass;	/* our mt device class */
>  	struct timer_list release_timer;	/* to release sticky fingers */
> +	struct hid_device *hdev;	/* hid_device we're attached to */
>  	struct mt_fields *fields;	/* temporary placeholder for storing the
>  					   multitouch fields */
>  	unsigned long mt_io_flags;	/* mt flags (MT_IO_FLAGS_*) */
> @@ -1245,10 +1246,10 @@ static void mt_release_contacts(struct hid_device *hid)
>  	td->num_received = 0;
>  }
>  
> -static void mt_expired_timeout(unsigned long arg)
> +static void mt_expired_timeout(struct timer_list *t)
>  {
> -	struct hid_device *hdev = (void *)arg;
> -	struct mt_device *td = hid_get_drvdata(hdev);
> +	struct mt_device *td = from_timer(td, t, release_timer);
> +	struct hid_device *hdev = td->hdev;
>  
>  	/*
>  	 * An input report came in just before we release the sticky fingers,
> @@ -1279,6 +1280,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  		dev_err(&hdev->dev, "cannot allocate multitouch data\n");
>  		return -ENOMEM;
>  	}
> +	td->hdev = hdev;
>  	td->mtclass = *mtclass;
>  	td->inputmode = -1;
>  	td->maxcontact_report_id = -1;
> @@ -1330,7 +1332,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  	 */
>  	hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
>  
> -	setup_timer(&td->release_timer, mt_expired_timeout, (long)hdev);
> +	timer_setup(&td->release_timer, mt_expired_timeout, 0);
>  
>  	ret = hid_parse(hdev);
>  	if (ret != 0)
> diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
> index 089bad8a9a21..9f9fe0e58f5b 100644
> --- a/drivers/hid/usbhid/hid-core.c
> +++ b/drivers/hid/usbhid/hid-core.c
> @@ -101,10 +101,10 @@ static int hid_start_in(struct hid_device *hid)
>  }
>  
>  /* I/O retry timer routine */
> -static void hid_retry_timeout(unsigned long _hid)
> +static void hid_retry_timeout(struct timer_list *t)
>  {
> -	struct hid_device *hid = (struct hid_device *) _hid;
> -	struct usbhid_device *usbhid = hid->driver_data;
> +	struct usbhid_device *usbhid = from_timer(usbhid, t, io_retry);
> +	struct hid_device *hid = usbhid->hid;
>  
>  	dev_dbg(&usbhid->intf->dev, "retrying intr urb\n");
>  	if (hid_start_in(hid))
> @@ -1363,7 +1363,7 @@ static int usbhid_probe(struct usb_interface *intf, const struct usb_device_id *
>  
>  	init_waitqueue_head(&usbhid->wait);
>  	INIT_WORK(&usbhid->reset_work, hid_reset);
> -	setup_timer(&usbhid->io_retry, hid_retry_timeout, (unsigned long) hid);
> +	timer_setup(&usbhid->io_retry, hid_retry_timeout, 0);
>  	spin_lock_init(&usbhid->lock);
>  
>  	ret = hid_add_device(hid);
> -- 
> 2.7.4
> 
> 
> -- 
> Kees Cook
> Pixel Security