2023-12-01 12:04:57

by Marcus Folkesson

[permalink] [raw]
Subject: [PATCH] Input: pxrc - simplify mutex handling with guard macro

Use the guard(mutex) macro for handle mutex lock/unlocks.

Signed-off-by: Marcus Folkesson <[email protected]>
---
drivers/input/joystick/pxrc.c | 27 +++++++++++----------------
1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/drivers/input/joystick/pxrc.c b/drivers/input/joystick/pxrc.c
index ea2bf5951d67..3c3bf7179b46 100644
--- a/drivers/input/joystick/pxrc.c
+++ b/drivers/input/joystick/pxrc.c
@@ -5,15 +5,17 @@
* Copyright (C) 2018 Marcus Folkesson <[email protected]>
*/

-#include <linux/kernel.h>
+#include <linux/cleanup.h>
#include <linux/errno.h>
-#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
#include <linux/uaccess.h>
+
#include <linux/usb.h>
#include <linux/usb/input.h>
-#include <linux/mutex.h>
-#include <linux/input.h>

#define PXRC_VENDOR_ID 0x1781
#define PXRC_PRODUCT_ID 0x0898
@@ -89,25 +91,20 @@ static int pxrc_open(struct input_dev *input)
dev_err(&pxrc->intf->dev,
"%s - usb_submit_urb failed, error: %d\n",
__func__, retval);
- retval = -EIO;
- goto out;
+ return -EIO;
}

pxrc->is_open = true;
-
-out:
- mutex_unlock(&pxrc->pm_mutex);
- return retval;
+ return 0;
}

static void pxrc_close(struct input_dev *input)
{
struct pxrc *pxrc = input_get_drvdata(input);

- mutex_lock(&pxrc->pm_mutex);
+ guard(mutex)(&pxrc->pm_mutex);
usb_kill_urb(pxrc->urb);
pxrc->is_open = false;
- mutex_unlock(&pxrc->pm_mutex);
}

static void pxrc_free_urb(void *_pxrc)
@@ -208,10 +205,9 @@ static int pxrc_suspend(struct usb_interface *intf, pm_message_t message)
{
struct pxrc *pxrc = usb_get_intfdata(intf);

- mutex_lock(&pxrc->pm_mutex);
+ guard(mutex)(&pxrc->pm_mutex);
if (pxrc->is_open)
usb_kill_urb(pxrc->urb);
- mutex_unlock(&pxrc->pm_mutex);

return 0;
}
@@ -221,11 +217,10 @@ static int pxrc_resume(struct usb_interface *intf)
struct pxrc *pxrc = usb_get_intfdata(intf);
int retval = 0;

- mutex_lock(&pxrc->pm_mutex);
+ guard(mutex)(&pxrc->pm_mutex);
if (pxrc->is_open && usb_submit_urb(pxrc->urb, GFP_KERNEL) < 0)
retval = -EIO;

- mutex_unlock(&pxrc->pm_mutex);
return retval;
}


---
base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
change-id: 20231201-pxrc-guard-03dc35771b36

Best regards,
--
Marcus Folkesson <[email protected]>


2023-12-01 13:28:59

by Johan Hovold

[permalink] [raw]
Subject: Re: [PATCH] Input: pxrc - simplify mutex handling with guard macro

On Fri, Dec 01, 2023 at 01:08:45PM +0100, Marcus Folkesson wrote:
> Use the guard(mutex) macro for handle mutex lock/unlocks.
>
> Signed-off-by: Marcus Folkesson <[email protected]>

A couple of drive-by comments below.

> ---
> drivers/input/joystick/pxrc.c | 27 +++++++++++----------------
> 1 file changed, 11 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/input/joystick/pxrc.c b/drivers/input/joystick/pxrc.c
> index ea2bf5951d67..3c3bf7179b46 100644
> --- a/drivers/input/joystick/pxrc.c
> +++ b/drivers/input/joystick/pxrc.c
> @@ -5,15 +5,17 @@
> * Copyright (C) 2018 Marcus Folkesson <[email protected]>
> */
>
> -#include <linux/kernel.h>
> +#include <linux/cleanup.h>
> #include <linux/errno.h>
> -#include <linux/slab.h>
> +#include <linux/input.h>
> +#include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> #include <linux/uaccess.h>
> +
> #include <linux/usb.h>
> #include <linux/usb/input.h>
> -#include <linux/mutex.h>
> -#include <linux/input.h>

Looks like an unrelated change.

> #define PXRC_VENDOR_ID 0x1781
> #define PXRC_PRODUCT_ID 0x0898
> @@ -89,25 +91,20 @@ static int pxrc_open(struct input_dev *input)
> dev_err(&pxrc->intf->dev,
> "%s - usb_submit_urb failed, error: %d\n",
> __func__, retval);
> - retval = -EIO;
> - goto out;
> + return -EIO;
> }
>
> pxrc->is_open = true;
> -
> -out:
> - mutex_unlock(&pxrc->pm_mutex);
> - return retval;
> + return 0;
> }

Eh, this looks obviously broken. Did you not test this before
submitting? I assume lockdep would complain loudly too.

You're apparently the author of this driver and can test it, but I fear
the coming onslaught of untested guard conversions from the "cleanup"
crew. Not sure I find the result generally more readable either.

Johan

2023-12-01 13:43:53

by Marcus Folkesson

[permalink] [raw]
Subject: Re: [PATCH] Input: pxrc - simplify mutex handling with guard macro

On Fri, Dec 01, 2023 at 02:29:22PM +0100, Johan Hovold wrote:
> On Fri, Dec 01, 2023 at 01:08:45PM +0100, Marcus Folkesson wrote:
> > Use the guard(mutex) macro for handle mutex lock/unlocks.
> >
> > Signed-off-by: Marcus Folkesson <[email protected]>
>
> A couple of drive-by comments below.
>
> > ---
> > drivers/input/joystick/pxrc.c | 27 +++++++++++----------------
> > 1 file changed, 11 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/input/joystick/pxrc.c b/drivers/input/joystick/pxrc.c
> > index ea2bf5951d67..3c3bf7179b46 100644
> > --- a/drivers/input/joystick/pxrc.c
> > +++ b/drivers/input/joystick/pxrc.c
> > @@ -5,15 +5,17 @@
> > * Copyright (C) 2018 Marcus Folkesson <[email protected]>
> > */
> >
> > -#include <linux/kernel.h>
> > +#include <linux/cleanup.h>
> > #include <linux/errno.h>
> > -#include <linux/slab.h>
> > +#include <linux/input.h>
> > +#include <linux/kernel.h>
> > #include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/slab.h>
> > #include <linux/uaccess.h>
> > +
> > #include <linux/usb.h>
> > #include <linux/usb/input.h>
> > -#include <linux/mutex.h>
> > -#include <linux/input.h>
>
> Looks like an unrelated change.

I reordered the include files as I added cleanup.h.
I can do it in a separate patch if that is preferred.

>
> > #define PXRC_VENDOR_ID 0x1781
> > #define PXRC_PRODUCT_ID 0x0898
> > @@ -89,25 +91,20 @@ static int pxrc_open(struct input_dev *input)
> > dev_err(&pxrc->intf->dev,
> > "%s - usb_submit_urb failed, error: %d\n",
> > __func__, retval);
> > - retval = -EIO;
> > - goto out;
> > + return -EIO;
> > }
> >
> > pxrc->is_open = true;
> > -
> > -out:
> > - mutex_unlock(&pxrc->pm_mutex);
> > - return retval;
> > + return 0;
> > }
>
> Eh, this looks obviously broken. Did you not test this before
> submitting? I assume lockdep would complain loudly too.

Sorry, it is more that I'm not in the habit of using b4 for submitting
patches yet, so things got wrong.
There is a v2 out there.

The driver (v2) is quickly tested on HW and, what I can tell, seems to behave.

>
> You're apparently the author of this driver and can test it, but I fear
> the coming onslaught of untested guard conversions from the "cleanup"
> crew. Not sure I find the result generally more readable either.
>
> Johan


Best regards
Marcus Folkesson


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2023-12-01 14:03:25

by Johan Hovold

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Subject: Re: [PATCH] Input: pxrc - simplify mutex handling with guard macro

On Fri, Dec 01, 2023 at 02:48:06PM +0100, Marcus Folkesson wrote:
> On Fri, Dec 01, 2023 at 02:29:22PM +0100, Johan Hovold wrote:

> > Eh, this looks obviously broken. Did you not test this before
> > submitting? I assume lockdep would complain loudly too.
>
> Sorry, it is more that I'm not in the habit of using b4 for submitting
> patches yet, so things got wrong.
> There is a v2 out there.

Ah, good, you noticed yourself.

Johan


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2023-12-01 23:33:35

by Dmitry Torokhov

[permalink] [raw]
Subject: Re: [PATCH] Input: pxrc - simplify mutex handling with guard macro

On Fri, Dec 01, 2023 at 02:29:22PM +0100, Johan Hovold wrote:
> On Fri, Dec 01, 2023 at 01:08:45PM +0100, Marcus Folkesson wrote:
> > Use the guard(mutex) macro for handle mutex lock/unlocks.
> >
> > Signed-off-by: Marcus Folkesson <[email protected]>
>
> A couple of drive-by comments below.
>
> > ---
> > drivers/input/joystick/pxrc.c | 27 +++++++++++----------------
> > 1 file changed, 11 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/input/joystick/pxrc.c b/drivers/input/joystick/pxrc.c
> > index ea2bf5951d67..3c3bf7179b46 100644
> > --- a/drivers/input/joystick/pxrc.c
> > +++ b/drivers/input/joystick/pxrc.c
> > @@ -5,15 +5,17 @@
> > * Copyright (C) 2018 Marcus Folkesson <[email protected]>
> > */
> >
> > -#include <linux/kernel.h>
> > +#include <linux/cleanup.h>
> > #include <linux/errno.h>
> > -#include <linux/slab.h>
> > +#include <linux/input.h>
> > +#include <linux/kernel.h>
> > #include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/slab.h>
> > #include <linux/uaccess.h>
> > +
> > #include <linux/usb.h>
> > #include <linux/usb/input.h>
> > -#include <linux/mutex.h>
> > -#include <linux/input.h>
>
> Looks like an unrelated change.
>
> > #define PXRC_VENDOR_ID 0x1781
> > #define PXRC_PRODUCT_ID 0x0898
> > @@ -89,25 +91,20 @@ static int pxrc_open(struct input_dev *input)
> > dev_err(&pxrc->intf->dev,
> > "%s - usb_submit_urb failed, error: %d\n",
> > __func__, retval);
> > - retval = -EIO;
> > - goto out;
> > + return -EIO;
> > }
> >
> > pxrc->is_open = true;
> > -
> > -out:
> > - mutex_unlock(&pxrc->pm_mutex);
> > - return retval;
> > + return 0;
> > }
>
> Eh, this looks obviously broken. Did you not test this before
> submitting? I assume lockdep would complain loudly too.
>
> You're apparently the author of this driver and can test it, but I fear
> the coming onslaught of untested guard conversions from the "cleanup"
> crew. Not sure I find the result generally more readable either.

Yeah, for the code without conditions (like pxrc_close) the utility is
questionable, but I guess it is just a matter of getting used to the new
facilities...

Thanks.

--
Dmitry