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Message-ID: <a41bb88a-b624-4b5b-a2ea-b49761c45a93@gmail.com>
Date: Wed, 4 Sep 2024 21:52:21 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>, linux-input@...r.kernel.org
Cc: Michael Hennerich <michael.hennerich@...log.com>,
Ville Syrjala <syrjala@....fi>,
Support Opensource <support.opensource@...semi.com>,
Eddie James <eajames@...ux.ibm.com>, Andrey Moiseev <o2g.org.ru@...il.com>,
Hans de Goede <hdegoede@...hat.com>, Jeff LaBundy <jeff@...undy.com>,
linux-kernel@...r.kernel.org,
Javier Carrasco Cruz <javier.carrasco.cruz@...il.com>
Subject: Re: [PATCH 17/22] Input: pegasus_notetaker - use guard notation when
acquiring mutex
On 04/09/2024 06:48, Dmitry Torokhov wrote:
> Using guard notation makes the code more compact and error handling
> more robust by ensuring that mutexes are released in all code paths
> when control leaves critical section.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> ---
> drivers/input/tablet/pegasus_notetaker.c | 86 +++++++++++++-----------
> 1 file changed, 48 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/input/tablet/pegasus_notetaker.c b/drivers/input/tablet/pegasus_notetaker.c
> index a68da2988f9c..e1dc8365bfe9 100644
> --- a/drivers/input/tablet/pegasus_notetaker.c
> +++ b/drivers/input/tablet/pegasus_notetaker.c
> @@ -214,6 +214,28 @@ static void pegasus_init(struct work_struct *work)
> error);
> }
>
> +static int __pegasus_open(struct pegasus *pegasus)
> +{
> + int error;
> +
> + guard(mutex)(&pegasus->pm_mutex);
> +
> + pegasus->irq->dev = pegasus->usbdev;
> + if (usb_submit_urb(pegasus->irq, GFP_KERNEL))
> + return -EIO;
> +
> + error = pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
> + if (error) {
> + usb_kill_urb(pegasus->irq);
> + cancel_work_sync(&pegasus->init);
> + return error;
> + }
> +
> + pegasus->is_open = true;
Nit: blank line before return.
> + return 0;
> +}
Nit: multiple blank lines.
> +
> +
> static int pegasus_open(struct input_dev *dev)
> {
> struct pegasus *pegasus = input_get_drvdata(dev);
> @@ -223,39 +245,25 @@ static int pegasus_open(struct input_dev *dev)
> if (error)
> return error;
>
> - mutex_lock(&pegasus->pm_mutex);
> - pegasus->irq->dev = pegasus->usbdev;
> - if (usb_submit_urb(pegasus->irq, GFP_KERNEL)) {
> - error = -EIO;
> - goto err_autopm_put;
> + error = __pegasus_open(pegasus);
> + if (error) {
> + usb_autopm_put_interface(pegasus->intf);
> + return error;
> }
>
> - error = pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
> - if (error)
> - goto err_kill_urb;
> -
> - pegasus->is_open = true;
> - mutex_unlock(&pegasus->pm_mutex);
> return 0;
> -
> -err_kill_urb:
> - usb_kill_urb(pegasus->irq);
> - cancel_work_sync(&pegasus->init);
> -err_autopm_put:
> - mutex_unlock(&pegasus->pm_mutex);
> - usb_autopm_put_interface(pegasus->intf);
> - return error;
> }
>
> static void pegasus_close(struct input_dev *dev)
> {
> struct pegasus *pegasus = input_get_drvdata(dev);
>
> - mutex_lock(&pegasus->pm_mutex);
> - usb_kill_urb(pegasus->irq);
> - cancel_work_sync(&pegasus->init);
> - pegasus->is_open = false;
> - mutex_unlock(&pegasus->pm_mutex);
> + scoped_guard(mutex, &pegasus->pm_mutex) {
> + usb_kill_urb(pegasus->irq);
> + cancel_work_sync(&pegasus->init);
> +
> + pegasus->is_open = false;
> + }
>
> usb_autopm_put_interface(pegasus->intf);
> }
> @@ -411,10 +419,10 @@ static int pegasus_suspend(struct usb_interface *intf, pm_message_t message)
> {
> struct pegasus *pegasus = usb_get_intfdata(intf);
>
> - mutex_lock(&pegasus->pm_mutex);
> + guard(mutex)(&pegasus->pm_mutex);
> +
> usb_kill_urb(pegasus->irq);
> cancel_work_sync(&pegasus->init);
> - mutex_unlock(&pegasus->pm_mutex);
>
> return 0;
> }
> @@ -422,31 +430,33 @@ static int pegasus_suspend(struct usb_interface *intf, pm_message_t message)
> static int pegasus_resume(struct usb_interface *intf)
> {
> struct pegasus *pegasus = usb_get_intfdata(intf);
> - int retval = 0;
>
> - mutex_lock(&pegasus->pm_mutex);
> + guard(mutex)(&pegasus->pm_mutex);
> +
> if (pegasus->is_open && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
> - retval = -EIO;
> - mutex_unlock(&pegasus->pm_mutex);
> + return -EIO;
>
> - return retval;
> + return 0;
> }
>
> static int pegasus_reset_resume(struct usb_interface *intf)
> {
> struct pegasus *pegasus = usb_get_intfdata(intf);
> - int retval = 0;
> + int error;
> +
> + guard(mutex)(&pegasus->pm_mutex);
>
> - mutex_lock(&pegasus->pm_mutex);
> if (pegasus->is_open) {
> - retval = pegasus_set_mode(pegasus, PEN_MODE_XY,
> + error = pegasus_set_mode(pegasus, PEN_MODE_XY,
> NOTETAKER_LED_MOUSE);
> - if (!retval && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
> - retval = -EIO;
> + if (error)
> + return error;
> +
> + if (usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
> + return -EIO;
> }
> - mutex_unlock(&pegasus->pm_mutex);
>
> - return retval;
> + return 0;
> }
>
> static const struct usb_device_id pegasus_ids[] = {
Apart from the minor nitpicks,
Reviewed-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
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