[PATCH 0/6] Convert joystick drivers to use new cleanup facilities

[PATCH 0/6] Convert joystick drivers to use new cleanup facilities

[Dmitry Torokhov]

Hi,

This series converts drivers found in drivers/input/keyboard to use new
__free() and guard() cleanup facilities that simplify the code and
ensure that all resources are released appropriately.

Thanks!

Dmitry Torokhov (6):
  Input: db9 - use guard notation when acquiring mutex
  Input: gamecon - use guard notation when acquiring mutex
  Input: iforce - use guard notation when acquiring mutex and spinlock
  Input: n64joy - use guard notation when acquiring mutex
  Input: turbografx - use guard notation when acquiring mutex
  Input: xpad - use guard notation when acquiring mutex and spinlock

 drivers/input/joystick/db9.c                  | 30 +++---
 drivers/input/joystick/gamecon.c              | 22 ++---
 drivers/input/joystick/iforce/iforce-ff.c     | 48 +++++----
 .../input/joystick/iforce/iforce-packets.c    | 57 +++++------
 drivers/input/joystick/iforce/iforce-serio.c  | 36 +++----
 drivers/input/joystick/iforce/iforce-usb.c    | 13 ++-
 drivers/input/joystick/n64joy.c               | 35 +++----
 drivers/input/joystick/turbografx.c           | 22 ++---
 drivers/input/joystick/xpad.c                 | 99 +++++++------------
 9 files changed, 152 insertions(+), 210 deletions(-)

-- 
Dmitry

[PATCH 1/6] Input: db9 - use guard notation when acquiring mutex

[Dmitry Torokhov]

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@gmail.com>
---
 drivers/input/joystick/db9.c | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/input/joystick/db9.c b/drivers/input/joystick/db9.c
index 682a29c27832..7ac0cfc3e786 100644
--- a/drivers/input/joystick/db9.c
+++ b/drivers/input/joystick/db9.c
@@ -505,24 +505,22 @@ static int db9_open(struct input_dev *dev)
 {
 	struct db9 *db9 = input_get_drvdata(dev);
 	struct parport *port = db9->pd->port;
-	int err;
 
-	err = mutex_lock_interruptible(&db9->mutex);
-	if (err)
-		return err;
-
-	if (!db9->used++) {
-		parport_claim(db9->pd);
-		parport_write_data(port, 0xff);
-		if (db9_modes[db9->mode].reverse) {
-			parport_data_reverse(port);
-			parport_write_control(port, DB9_NORMAL);
+	scoped_guard(mutex_intr, &db9->mutex) {
+		if (!db9->used++) {
+			parport_claim(db9->pd);
+			parport_write_data(port, 0xff);
+			if (db9_modes[db9->mode].reverse) {
+				parport_data_reverse(port);
+				parport_write_control(port, DB9_NORMAL);
+			}
+			mod_timer(&db9->timer, jiffies + DB9_REFRESH_TIME);
 		}
-		mod_timer(&db9->timer, jiffies + DB9_REFRESH_TIME);
+
+		return 0;
 	}
 
-	mutex_unlock(&db9->mutex);
-	return 0;
+	return -EINTR;
 }
 
 static void db9_close(struct input_dev *dev)
@@ -530,14 +528,14 @@ static void db9_close(struct input_dev *dev)
 	struct db9 *db9 = input_get_drvdata(dev);
 	struct parport *port = db9->pd->port;
 
-	mutex_lock(&db9->mutex);
+	guard(mutex)(&db9->mutex);
+
 	if (!--db9->used) {
 		del_timer_sync(&db9->timer);
 		parport_write_control(port, 0x00);
 		parport_data_forward(port);
 		parport_release(db9->pd);
 	}
-	mutex_unlock(&db9->mutex);
 }
 
 static void db9_attach(struct parport *pp)
-- 
2.46.0.469.g59c65b2a67-goog

Re: [PATCH 1/6] Input: db9 - use guard notation when acquiring mutex

[David Lechner]

On 9/3/24 11:30 PM, 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@gmail.com>
> ---
>  drivers/input/joystick/db9.c | 30 ++++++++++++++----------------
>  1 file changed, 14 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/input/joystick/db9.c b/drivers/input/joystick/db9.c
> index 682a29c27832..7ac0cfc3e786 100644
> --- a/drivers/input/joystick/db9.c
> +++ b/drivers/input/joystick/db9.c
> @@ -505,24 +505,22 @@ static int db9_open(struct input_dev *dev)
>  {
>  	struct db9 *db9 = input_get_drvdata(dev);
>  	struct parport *port = db9->pd->port;
> -	int err;
>  
> -	err = mutex_lock_interruptible(&db9->mutex);
> -	if (err)
> -		return err;
> -
> -	if (!db9->used++) {
> -		parport_claim(db9->pd);
> -		parport_write_data(port, 0xff);
> -		if (db9_modes[db9->mode].reverse) {
> -			parport_data_reverse(port);
> -			parport_write_control(port, DB9_NORMAL);
> +	scoped_guard(mutex_intr, &db9->mutex) {
> +		if (!db9->used++) {
> +			parport_claim(db9->pd);
> +			parport_write_data(port, 0xff);
> +			if (db9_modes[db9->mode].reverse) {
> +				parport_data_reverse(port);
> +				parport_write_control(port, DB9_NORMAL);
> +			}
> +			mod_timer(&db9->timer, jiffies + DB9_REFRESH_TIME);
>  		}
> -		mod_timer(&db9->timer, jiffies + DB9_REFRESH_TIME);
> +
> +		return 0;
>  	}
>  
> -	mutex_unlock(&db9->mutex);
> -	return 0;
> +	return -EINTR;

This patch and any others like it are potentially introducing a bug.

From inspecting the source code, it looks like
mutex_lock_interruptible() can return -EINTR, -EALREADY, or -EDEADLK.

Before this patch, the return value of mutex_lock_interruptible() was
passed to the caller. Now, the return value is reduced to pass/fail
and only -EINTR is returned on failure when the reason could have
been something else.

Re: [PATCH 1/6] Input: db9 - use guard notation when acquiring mutex

[Dmitry Torokhov]

On Wed, Nov 20, 2024 at 12:33:36PM -0600, David Lechner wrote:
> On 9/3/24 11:30 PM, 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@gmail.com>
> > ---
> >  drivers/input/joystick/db9.c | 30 ++++++++++++++----------------
> >  1 file changed, 14 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/input/joystick/db9.c b/drivers/input/joystick/db9.c
> > index 682a29c27832..7ac0cfc3e786 100644
> > --- a/drivers/input/joystick/db9.c
> > +++ b/drivers/input/joystick/db9.c
> > @@ -505,24 +505,22 @@ static int db9_open(struct input_dev *dev)
> >  {
> >  	struct db9 *db9 = input_get_drvdata(dev);
> >  	struct parport *port = db9->pd->port;
> > -	int err;
> >  
> > -	err = mutex_lock_interruptible(&db9->mutex);
> > -	if (err)
> > -		return err;
> > -
> > -	if (!db9->used++) {
> > -		parport_claim(db9->pd);
> > -		parport_write_data(port, 0xff);
> > -		if (db9_modes[db9->mode].reverse) {
> > -			parport_data_reverse(port);
> > -			parport_write_control(port, DB9_NORMAL);
> > +	scoped_guard(mutex_intr, &db9->mutex) {
> > +		if (!db9->used++) {
> > +			parport_claim(db9->pd);
> > +			parport_write_data(port, 0xff);
> > +			if (db9_modes[db9->mode].reverse) {
> > +				parport_data_reverse(port);
> > +				parport_write_control(port, DB9_NORMAL);
> > +			}
> > +			mod_timer(&db9->timer, jiffies + DB9_REFRESH_TIME);
> >  		}
> > -		mod_timer(&db9->timer, jiffies + DB9_REFRESH_TIME);
> > +
> > +		return 0;
> >  	}
> >  
> > -	mutex_unlock(&db9->mutex);
> > -	return 0;
> > +	return -EINTR;
> 
> This patch and any others like it are potentially introducing a bug.
> 
> From inspecting the source code, it looks like
> mutex_lock_interruptible() can return -EINTR, -EALREADY, or -EDEADLK.
> 
> Before this patch, the return value of mutex_lock_interruptible() was
> passed to the caller. Now, the return value is reduced to pass/fail
> and only -EINTR is returned on failure when the reason could have
> been something else.

It is documented that mutex_lock_interruptible() only returns 0 or
-EINTR. These additional errors only returned from __mutex_lock_common()
for WW mutexes.

If there is another form of scoped_cond_guard() that would make
available error code returned by the constructor of the locking
primitive we can switch to it later.

Thanks.

-- 
Dmitry

[PATCH 2/6] Input: gamecon - use guard notation when acquiring mutex

[Dmitry Torokhov]

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@gmail.com>
---
 drivers/input/joystick/gamecon.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/input/joystick/gamecon.c b/drivers/input/joystick/gamecon.c
index c38de3094553..968c0e653f2e 100644
--- a/drivers/input/joystick/gamecon.c
+++ b/drivers/input/joystick/gamecon.c
@@ -765,33 +765,31 @@ static void gc_timer(struct timer_list *t)
 static int gc_open(struct input_dev *dev)
 {
 	struct gc *gc = input_get_drvdata(dev);
-	int err;
 
-	err = mutex_lock_interruptible(&gc->mutex);
-	if (err)
-		return err;
+	scoped_guard(mutex_intr, &gc->mutex) {
+		if (!gc->used++) {
+			parport_claim(gc->pd);
+			parport_write_control(gc->pd->port, 0x04);
+			mod_timer(&gc->timer, jiffies + GC_REFRESH_TIME);
+		}
 
-	if (!gc->used++) {
-		parport_claim(gc->pd);
-		parport_write_control(gc->pd->port, 0x04);
-		mod_timer(&gc->timer, jiffies + GC_REFRESH_TIME);
+		return 0;
 	}
 
-	mutex_unlock(&gc->mutex);
-	return 0;
+	return -EINTR;
 }
 
 static void gc_close(struct input_dev *dev)
 {
 	struct gc *gc = input_get_drvdata(dev);
 
-	mutex_lock(&gc->mutex);
+	guard(mutex)(&gc->mutex);
+
 	if (!--gc->used) {
 		del_timer_sync(&gc->timer);
 		parport_write_control(gc->pd->port, 0x00);
 		parport_release(gc->pd);
 	}
-	mutex_unlock(&gc->mutex);
 }
 
 static int gc_setup_pad(struct gc *gc, int idx, int pad_type)
-- 
2.46.0.469.g59c65b2a67-goog

[PATCH 3/6] Input: iforce - use guard notation when acquiring mutex and spinlock

[Dmitry Torokhov]

Using guard notation makes the code more compact and error handling
more robust by ensuring that locks are released in all code paths
when control leaves critical section.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/joystick/iforce/iforce-ff.c     | 48 +++++++---------
 .../input/joystick/iforce/iforce-packets.c    | 57 ++++++++-----------
 drivers/input/joystick/iforce/iforce-serio.c  | 36 +++++-------
 drivers/input/joystick/iforce/iforce-usb.c    | 13 ++---
 4 files changed, 68 insertions(+), 86 deletions(-)

diff --git a/drivers/input/joystick/iforce/iforce-ff.c b/drivers/input/joystick/iforce/iforce-ff.c
index 95c0348843e6..8c78cbe553c8 100644
--- a/drivers/input/joystick/iforce/iforce-ff.c
+++ b/drivers/input/joystick/iforce/iforce-ff.c
@@ -21,14 +21,13 @@ static int make_magnitude_modifier(struct iforce* iforce,
 	unsigned char data[3];
 
 	if (!no_alloc) {
-		mutex_lock(&iforce->mem_mutex);
-		if (allocate_resource(&(iforce->device_memory), mod_chunk, 2,
-			iforce->device_memory.start, iforce->device_memory.end, 2L,
-			NULL, NULL)) {
-			mutex_unlock(&iforce->mem_mutex);
+		guard(mutex)(&iforce->mem_mutex);
+
+		if (allocate_resource(&iforce->device_memory, mod_chunk, 2,
+				      iforce->device_memory.start,
+				      iforce->device_memory.end,
+				      2L, NULL, NULL))
 			return -ENOSPC;
-		}
-		mutex_unlock(&iforce->mem_mutex);
 	}
 
 	data[0] = LO(mod_chunk->start);
@@ -54,14 +53,13 @@ static int make_period_modifier(struct iforce* iforce,
 	period = TIME_SCALE(period);
 
 	if (!no_alloc) {
-		mutex_lock(&iforce->mem_mutex);
-		if (allocate_resource(&(iforce->device_memory), mod_chunk, 0x0c,
-			iforce->device_memory.start, iforce->device_memory.end, 2L,
-			NULL, NULL)) {
-			mutex_unlock(&iforce->mem_mutex);
+		guard(mutex)(&iforce->mem_mutex);
+
+		if (allocate_resource(&iforce->device_memory, mod_chunk, 0x0c,
+				      iforce->device_memory.start,
+				      iforce->device_memory.end,
+				      2L, NULL, NULL))
 			return -ENOSPC;
-		}
-		mutex_unlock(&iforce->mem_mutex);
 	}
 
 	data[0] = LO(mod_chunk->start);
@@ -94,14 +92,13 @@ static int make_envelope_modifier(struct iforce* iforce,
 	fade_duration = TIME_SCALE(fade_duration);
 
 	if (!no_alloc) {
-		mutex_lock(&iforce->mem_mutex);
+		guard(mutex)(&iforce->mem_mutex);
+
 		if (allocate_resource(&(iforce->device_memory), mod_chunk, 0x0e,
-			iforce->device_memory.start, iforce->device_memory.end, 2L,
-			NULL, NULL)) {
-			mutex_unlock(&iforce->mem_mutex);
+				      iforce->device_memory.start,
+				      iforce->device_memory.end,
+				      2L, NULL, NULL))
 			return -ENOSPC;
-		}
-		mutex_unlock(&iforce->mem_mutex);
 	}
 
 	data[0] = LO(mod_chunk->start);
@@ -131,14 +128,13 @@ static int make_condition_modifier(struct iforce* iforce,
 	unsigned char data[10];
 
 	if (!no_alloc) {
-		mutex_lock(&iforce->mem_mutex);
+		guard(mutex)(&iforce->mem_mutex);
+
 		if (allocate_resource(&(iforce->device_memory), mod_chunk, 8,
-			iforce->device_memory.start, iforce->device_memory.end, 2L,
-			NULL, NULL)) {
-			mutex_unlock(&iforce->mem_mutex);
+				      iforce->device_memory.start,
+				      iforce->device_memory.end,
+				      2L, NULL, NULL))
 			return -ENOSPC;
-		}
-		mutex_unlock(&iforce->mem_mutex);
 	}
 
 	data[0] = LO(mod_chunk->start);
diff --git a/drivers/input/joystick/iforce/iforce-packets.c b/drivers/input/joystick/iforce/iforce-packets.c
index 763642c8cee9..8c2531e2977c 100644
--- a/drivers/input/joystick/iforce/iforce-packets.c
+++ b/drivers/input/joystick/iforce/iforce-packets.c
@@ -31,49 +31,42 @@ int iforce_send_packet(struct iforce *iforce, u16 cmd, unsigned char* data)
 	int c;
 	int empty;
 	int head, tail;
-	unsigned long flags;
 
 /*
  * Update head and tail of xmit buffer
  */
-	spin_lock_irqsave(&iforce->xmit_lock, flags);
-
-	head = iforce->xmit.head;
-	tail = iforce->xmit.tail;
-
-
-	if (CIRC_SPACE(head, tail, XMIT_SIZE) < n+2) {
-		dev_warn(&iforce->dev->dev,
-			 "not enough space in xmit buffer to send new packet\n");
-		spin_unlock_irqrestore(&iforce->xmit_lock, flags);
-		return -1;
-	}
+	scoped_guard(spinlock_irqsave, &iforce->xmit_lock) {
+		head = iforce->xmit.head;
+		tail = iforce->xmit.tail;
+
+		if (CIRC_SPACE(head, tail, XMIT_SIZE) < n + 2) {
+			dev_warn(&iforce->dev->dev,
+				 "not enough space in xmit buffer to send new packet\n");
+			return -1;
+		}
 
-	empty = head == tail;
-	XMIT_INC(iforce->xmit.head, n+2);
+		empty = head == tail;
+		XMIT_INC(iforce->xmit.head, n + 2);
 
 /*
  * Store packet in xmit buffer
  */
-	iforce->xmit.buf[head] = HI(cmd);
-	XMIT_INC(head, 1);
-	iforce->xmit.buf[head] = LO(cmd);
-	XMIT_INC(head, 1);
-
-	c = CIRC_SPACE_TO_END(head, tail, XMIT_SIZE);
-	if (n < c) c=n;
-
-	memcpy(&iforce->xmit.buf[head],
-	       data,
-	       c);
-	if (n != c) {
-		memcpy(&iforce->xmit.buf[0],
-		       data + c,
-		       n - c);
+		iforce->xmit.buf[head] = HI(cmd);
+		XMIT_INC(head, 1);
+		iforce->xmit.buf[head] = LO(cmd);
+		XMIT_INC(head, 1);
+
+		c = CIRC_SPACE_TO_END(head, tail, XMIT_SIZE);
+		if (n < c)
+			c = n;
+
+		memcpy(&iforce->xmit.buf[head], data, c);
+		if (n != c)
+			memcpy(&iforce->xmit.buf[0], data + c, n - c);
+
+		XMIT_INC(head, n);
 	}
-	XMIT_INC(head, n);
 
-	spin_unlock_irqrestore(&iforce->xmit_lock, flags);
 /*
  * If necessary, start the transmission
  */
diff --git a/drivers/input/joystick/iforce/iforce-serio.c b/drivers/input/joystick/iforce/iforce-serio.c
index 2380546d7978..75b85c46dfa4 100644
--- a/drivers/input/joystick/iforce/iforce-serio.c
+++ b/drivers/input/joystick/iforce/iforce-serio.c
@@ -28,45 +28,39 @@ static void iforce_serio_xmit(struct iforce *iforce)
 							 iforce);
 	unsigned char cs;
 	int i;
-	unsigned long flags;
 
 	if (test_and_set_bit(IFORCE_XMIT_RUNNING, iforce->xmit_flags)) {
 		set_bit(IFORCE_XMIT_AGAIN, iforce->xmit_flags);
 		return;
 	}
 
-	spin_lock_irqsave(&iforce->xmit_lock, flags);
+	guard(spinlock_irqsave)(&iforce->xmit_lock);
 
-again:
-	if (iforce->xmit.head == iforce->xmit.tail) {
-		iforce_clear_xmit_and_wake(iforce);
-		spin_unlock_irqrestore(&iforce->xmit_lock, flags);
-		return;
-	}
+	do {
+		if (iforce->xmit.head == iforce->xmit.tail)
+			break;
 
-	cs = 0x2b;
+		cs = 0x2b;
 
-	serio_write(iforce_serio->serio, 0x2b);
+		serio_write(iforce_serio->serio, 0x2b);
 
-	serio_write(iforce_serio->serio, iforce->xmit.buf[iforce->xmit.tail]);
-	cs ^= iforce->xmit.buf[iforce->xmit.tail];
-	XMIT_INC(iforce->xmit.tail, 1);
-
-	for (i=iforce->xmit.buf[iforce->xmit.tail]; i >= 0; --i) {
 		serio_write(iforce_serio->serio,
 			    iforce->xmit.buf[iforce->xmit.tail]);
 		cs ^= iforce->xmit.buf[iforce->xmit.tail];
 		XMIT_INC(iforce->xmit.tail, 1);
-	}
 
-	serio_write(iforce_serio->serio, cs);
+		for (i = iforce->xmit.buf[iforce->xmit.tail]; i >= 0; --i) {
+			serio_write(iforce_serio->serio,
+				    iforce->xmit.buf[iforce->xmit.tail]);
+			cs ^= iforce->xmit.buf[iforce->xmit.tail];
+			XMIT_INC(iforce->xmit.tail, 1);
+		}
 
-	if (test_and_clear_bit(IFORCE_XMIT_AGAIN, iforce->xmit_flags))
-		goto again;
+		serio_write(iforce_serio->serio, cs);
 
-	iforce_clear_xmit_and_wake(iforce);
+	} while (test_and_clear_bit(IFORCE_XMIT_AGAIN, iforce->xmit_flags));
 
-	spin_unlock_irqrestore(&iforce->xmit_lock, flags);
+	iforce_clear_xmit_and_wake(iforce);
 }
 
 static int iforce_serio_get_id(struct iforce *iforce, u8 id,
diff --git a/drivers/input/joystick/iforce/iforce-usb.c b/drivers/input/joystick/iforce/iforce-usb.c
index cba92bd590a8..1f00f76b0174 100644
--- a/drivers/input/joystick/iforce/iforce-usb.c
+++ b/drivers/input/joystick/iforce/iforce-usb.c
@@ -25,13 +25,11 @@ static void __iforce_usb_xmit(struct iforce *iforce)
 	struct iforce_usb *iforce_usb = container_of(iforce, struct iforce_usb,
 						     iforce);
 	int n, c;
-	unsigned long flags;
 
-	spin_lock_irqsave(&iforce->xmit_lock, flags);
+	guard(spinlock_irqsave)(&iforce->xmit_lock);
 
 	if (iforce->xmit.head == iforce->xmit.tail) {
 		iforce_clear_xmit_and_wake(iforce);
-		spin_unlock_irqrestore(&iforce->xmit_lock, flags);
 		return;
 	}
 
@@ -45,7 +43,8 @@ static void __iforce_usb_xmit(struct iforce *iforce)
 
 	/* Copy rest of data then */
 	c = CIRC_CNT_TO_END(iforce->xmit.head, iforce->xmit.tail, XMIT_SIZE);
-	if (n < c) c=n;
+	if (n < c)
+		c = n;
 
 	memcpy(iforce_usb->out->transfer_buffer + 1,
 	       &iforce->xmit.buf[iforce->xmit.tail],
@@ -53,11 +52,12 @@ static void __iforce_usb_xmit(struct iforce *iforce)
 	if (n != c) {
 		memcpy(iforce_usb->out->transfer_buffer + 1 + c,
 		       &iforce->xmit.buf[0],
-		       n-c);
+		       n - c);
 	}
 	XMIT_INC(iforce->xmit.tail, n);
 
-	if ( (n=usb_submit_urb(iforce_usb->out, GFP_ATOMIC)) ) {
+	n=usb_submit_urb(iforce_usb->out, GFP_ATOMIC);
+	if (n) {
 		dev_warn(&iforce_usb->intf->dev,
 			 "usb_submit_urb failed %d\n", n);
 		iforce_clear_xmit_and_wake(iforce);
@@ -66,7 +66,6 @@ static void __iforce_usb_xmit(struct iforce *iforce)
 	/* The IFORCE_XMIT_RUNNING bit is not cleared here. That's intended.
 	 * As long as the urb completion handler is not called, the transmiting
 	 * is considered to be running */
-	spin_unlock_irqrestore(&iforce->xmit_lock, flags);
 }
 
 static void iforce_usb_xmit(struct iforce *iforce)
-- 
2.46.0.469.g59c65b2a67-goog

[PATCH 4/6] Input: n64joy - use guard notation when acquiring mutex

[Dmitry Torokhov]

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@gmail.com>
---
 drivers/input/joystick/n64joy.c | 35 +++++++++++++++------------------
 1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/drivers/input/joystick/n64joy.c b/drivers/input/joystick/n64joy.c
index b0986d2195d6..c344dbc0c493 100644
--- a/drivers/input/joystick/n64joy.c
+++ b/drivers/input/joystick/n64joy.c
@@ -191,35 +191,32 @@ static void n64joy_poll(struct timer_list *t)
 static int n64joy_open(struct input_dev *dev)
 {
 	struct n64joy_priv *priv = input_get_drvdata(dev);
-	int err;
-
-	err = mutex_lock_interruptible(&priv->n64joy_mutex);
-	if (err)
-		return err;
-
-	if (!priv->n64joy_opened) {
-		/*
-		 * We could use the vblank irq, but it's not important if
-		 * the poll point slightly changes.
-		 */
-		timer_setup(&priv->timer, n64joy_poll, 0);
-		mod_timer(&priv->timer, jiffies + msecs_to_jiffies(16));
-	}
 
-	priv->n64joy_opened++;
+	scoped_guard(mutex_intr, &priv->n64joy_mutex) {
+		if (!priv->n64joy_opened) {
+			/*
+			 * We could use the vblank irq, but it's not important
+			 * if the poll point slightly changes.
+			 */
+			timer_setup(&priv->timer, n64joy_poll, 0);
+			mod_timer(&priv->timer, jiffies + msecs_to_jiffies(16));
+		}
 
-	mutex_unlock(&priv->n64joy_mutex);
-	return err;
+		priv->n64joy_opened++;
+		return 0;
+	}
+
+	return -EINTR;
 }
 
 static void n64joy_close(struct input_dev *dev)
 {
 	struct n64joy_priv *priv = input_get_drvdata(dev);
 
-	mutex_lock(&priv->n64joy_mutex);
+	guard(mutex)(&priv->n64joy_mutex);
+
 	if (!--priv->n64joy_opened)
 		del_timer_sync(&priv->timer);
-	mutex_unlock(&priv->n64joy_mutex);
 }
 
 static const u64 __initconst scandata[] ____cacheline_aligned = {
-- 
2.46.0.469.g59c65b2a67-goog

[PATCH 5/6] Input: turbografx - use guard notation when acquiring mutex

[Dmitry Torokhov]

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@gmail.com>
---
 drivers/input/joystick/turbografx.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/input/joystick/turbografx.c b/drivers/input/joystick/turbografx.c
index eb8455c34e67..015010a928aa 100644
--- a/drivers/input/joystick/turbografx.c
+++ b/drivers/input/joystick/turbografx.c
@@ -103,33 +103,31 @@ static void tgfx_timer(struct timer_list *t)
 static int tgfx_open(struct input_dev *dev)
 {
 	struct tgfx *tgfx = input_get_drvdata(dev);
-	int err;
 
-	err = mutex_lock_interruptible(&tgfx->sem);
-	if (err)
-		return err;
+	scoped_guard(mutex_intr, &tgfx->sem) {
+		if (!tgfx->used++) {
+			parport_claim(tgfx->pd);
+			parport_write_control(tgfx->pd->port, 0x04);
+			mod_timer(&tgfx->timer, jiffies + TGFX_REFRESH_TIME);
+		}
 
-	if (!tgfx->used++) {
-		parport_claim(tgfx->pd);
-		parport_write_control(tgfx->pd->port, 0x04);
-		mod_timer(&tgfx->timer, jiffies + TGFX_REFRESH_TIME);
+		return 0;
 	}
 
-	mutex_unlock(&tgfx->sem);
-	return 0;
+	return -EINTR;
 }
 
 static void tgfx_close(struct input_dev *dev)
 {
 	struct tgfx *tgfx = input_get_drvdata(dev);
 
-	mutex_lock(&tgfx->sem);
+	guard(mutex)(&tgfx->sem);
+
 	if (!--tgfx->used) {
 		del_timer_sync(&tgfx->timer);
 		parport_write_control(tgfx->pd->port, 0x00);
 		parport_release(tgfx->pd);
 	}
-	mutex_unlock(&tgfx->sem);
 }
 
 
-- 
2.46.0.469.g59c65b2a67-goog

[PATCH 6/6] Input: xpad - use guard notation when acquiring mutex and spinlock

[Dmitry Torokhov]

Using guard notation makes the code more compact and error handling
more robust by ensuring that locks are released in all code paths
when control leaves critical section.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/joystick/xpad.c | 99 ++++++++++++-----------------------
 1 file changed, 34 insertions(+), 65 deletions(-)

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index 4eda18f4f46e..3e61df927277 100644
--- a/drivers/input/joystick/xpad.c
+++ b/drivers/input/joystick/xpad.c
@@ -1289,9 +1289,8 @@ static void xpad_irq_out(struct urb *urb)
 	struct device *dev = &xpad->intf->dev;
 	int status = urb->status;
 	int error;
-	unsigned long flags;
 
-	spin_lock_irqsave(&xpad->odata_lock, flags);
+	guard(spinlock_irqsave)(&xpad->odata_lock);
 
 	switch (status) {
 	case 0:
@@ -1325,8 +1324,6 @@ static void xpad_irq_out(struct urb *urb)
 			xpad->irq_out_active = false;
 		}
 	}
-
-	spin_unlock_irqrestore(&xpad->odata_lock, flags);
 }
 
 static int xpad_init_output(struct usb_interface *intf, struct usb_xpad *xpad,
@@ -1391,10 +1388,8 @@ static int xpad_inquiry_pad_presence(struct usb_xpad *xpad)
 {
 	struct xpad_output_packet *packet =
 			&xpad->out_packets[XPAD_OUT_CMD_IDX];
-	unsigned long flags;
-	int retval;
 
-	spin_lock_irqsave(&xpad->odata_lock, flags);
+	guard(spinlock_irqsave)(&xpad->odata_lock);
 
 	packet->data[0] = 0x08;
 	packet->data[1] = 0x00;
@@ -1413,17 +1408,12 @@ static int xpad_inquiry_pad_presence(struct usb_xpad *xpad)
 
 	/* Reset the sequence so we send out presence first */
 	xpad->last_out_packet = -1;
-	retval = xpad_try_sending_next_out_packet(xpad);
-
-	spin_unlock_irqrestore(&xpad->odata_lock, flags);
-
-	return retval;
+	return xpad_try_sending_next_out_packet(xpad);
 }
 
 static int xpad_start_xbox_one(struct usb_xpad *xpad)
 {
-	unsigned long flags;
-	int retval;
+	int error;
 
 	if (usb_ifnum_to_if(xpad->udev, GIP_WIRED_INTF_AUDIO)) {
 		/*
@@ -1432,15 +1422,15 @@ static int xpad_start_xbox_one(struct usb_xpad *xpad)
 		 * Controller for Series X|S (0x20d6:0x200e) to report the
 		 * guide button.
 		 */
-		retval = usb_set_interface(xpad->udev,
-					   GIP_WIRED_INTF_AUDIO, 0);
-		if (retval)
+		error = usb_set_interface(xpad->udev,
+					  GIP_WIRED_INTF_AUDIO, 0);
+		if (error)
 			dev_warn(&xpad->dev->dev,
 				 "unable to disable audio interface: %d\n",
-				 retval);
+				 error);
 	}
 
-	spin_lock_irqsave(&xpad->odata_lock, flags);
+	guard(spinlock_irqsave)(&xpad->odata_lock);
 
 	/*
 	 * Begin the init sequence by attempting to send a packet.
@@ -1448,16 +1438,11 @@ static int xpad_start_xbox_one(struct usb_xpad *xpad)
 	 * sending any packets from the output ring.
 	 */
 	xpad->init_seq = 0;
-	retval = xpad_try_sending_next_out_packet(xpad);
-
-	spin_unlock_irqrestore(&xpad->odata_lock, flags);
-
-	return retval;
+	return xpad_try_sending_next_out_packet(xpad);
 }
 
 static void xpadone_ack_mode_report(struct usb_xpad *xpad, u8 seq_num)
 {
-	unsigned long flags;
 	struct xpad_output_packet *packet =
 			&xpad->out_packets[XPAD_OUT_CMD_IDX];
 	static const u8 mode_report_ack[] = {
@@ -1465,7 +1450,7 @@ static void xpadone_ack_mode_report(struct usb_xpad *xpad, u8 seq_num)
 		0x00, GIP_CMD_VIRTUAL_KEY, GIP_OPT_INTERNAL, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00
 	};
 
-	spin_lock_irqsave(&xpad->odata_lock, flags);
+	guard(spinlock_irqsave)(&xpad->odata_lock);
 
 	packet->len = sizeof(mode_report_ack);
 	memcpy(packet->data, mode_report_ack, packet->len);
@@ -1475,8 +1460,6 @@ static void xpadone_ack_mode_report(struct usb_xpad *xpad, u8 seq_num)
 	/* Reset the sequence so we send out the ack now */
 	xpad->last_out_packet = -1;
 	xpad_try_sending_next_out_packet(xpad);
-
-	spin_unlock_irqrestore(&xpad->odata_lock, flags);
 }
 
 #ifdef CONFIG_JOYSTICK_XPAD_FF
@@ -1486,8 +1469,6 @@ static int xpad_play_effect(struct input_dev *dev, void *data, struct ff_effect
 	struct xpad_output_packet *packet = &xpad->out_packets[XPAD_OUT_FF_IDX];
 	__u16 strong;
 	__u16 weak;
-	int retval;
-	unsigned long flags;
 
 	if (effect->type != FF_RUMBLE)
 		return 0;
@@ -1495,7 +1476,7 @@ static int xpad_play_effect(struct input_dev *dev, void *data, struct ff_effect
 	strong = effect->u.rumble.strong_magnitude;
 	weak = effect->u.rumble.weak_magnitude;
 
-	spin_lock_irqsave(&xpad->odata_lock, flags);
+	guard(spinlock_irqsave)(&xpad->odata_lock);
 
 	switch (xpad->xtype) {
 	case XTYPE_XBOX:
@@ -1561,15 +1542,10 @@ static int xpad_play_effect(struct input_dev *dev, void *data, struct ff_effect
 		dev_dbg(&xpad->dev->dev,
 			"%s - rumble command sent to unsupported xpad type: %d\n",
 			__func__, xpad->xtype);
-		retval = -EINVAL;
-		goto out;
+		return -EINVAL;
 	}
 
-	retval = xpad_try_sending_next_out_packet(xpad);
-
-out:
-	spin_unlock_irqrestore(&xpad->odata_lock, flags);
-	return retval;
+	return xpad_try_sending_next_out_packet(xpad);
 }
 
 static int xpad_init_ff(struct usb_xpad *xpad)
@@ -1622,11 +1598,10 @@ static void xpad_send_led_command(struct usb_xpad *xpad, int command)
 {
 	struct xpad_output_packet *packet =
 			&xpad->out_packets[XPAD_OUT_LED_IDX];
-	unsigned long flags;
 
 	command %= 16;
 
-	spin_lock_irqsave(&xpad->odata_lock, flags);
+	guard(spinlock_irqsave)(&xpad->odata_lock);
 
 	switch (xpad->xtype) {
 	case XTYPE_XBOX360:
@@ -1656,8 +1631,6 @@ static void xpad_send_led_command(struct usb_xpad *xpad, int command)
 	}
 
 	xpad_try_sending_next_out_packet(xpad);
-
-	spin_unlock_irqrestore(&xpad->odata_lock, flags);
 }
 
 /*
@@ -1782,11 +1755,10 @@ static void xpad_stop_input(struct usb_xpad *xpad)
 
 static void xpad360w_poweroff_controller(struct usb_xpad *xpad)
 {
-	unsigned long flags;
 	struct xpad_output_packet *packet =
 			&xpad->out_packets[XPAD_OUT_CMD_IDX];
 
-	spin_lock_irqsave(&xpad->odata_lock, flags);
+	guard(spinlock_irqsave)(&xpad->odata_lock);
 
 	packet->data[0] = 0x00;
 	packet->data[1] = 0x00;
@@ -1806,8 +1778,6 @@ static void xpad360w_poweroff_controller(struct usb_xpad *xpad)
 	/* Reset the sequence so we send out poweroff now */
 	xpad->last_out_packet = -1;
 	xpad_try_sending_next_out_packet(xpad);
-
-	spin_unlock_irqrestore(&xpad->odata_lock, flags);
 }
 
 static int xpad360w_start_input(struct usb_xpad *xpad)
@@ -2231,10 +2201,10 @@ static int xpad_suspend(struct usb_interface *intf, pm_message_t message)
 		if (auto_poweroff && xpad->pad_present)
 			xpad360w_poweroff_controller(xpad);
 	} else {
-		mutex_lock(&input->mutex);
+		guard(mutex)(&input->mutex);
+
 		if (input_device_enabled(input))
 			xpad_stop_input(xpad);
-		mutex_unlock(&input->mutex);
 	}
 
 	xpad_stop_output(xpad);
@@ -2246,26 +2216,25 @@ static int xpad_resume(struct usb_interface *intf)
 {
 	struct usb_xpad *xpad = usb_get_intfdata(intf);
 	struct input_dev *input = xpad->dev;
-	int retval = 0;
 
-	if (xpad->xtype == XTYPE_XBOX360W) {
-		retval = xpad360w_start_input(xpad);
-	} else {
-		mutex_lock(&input->mutex);
-		if (input_device_enabled(input)) {
-			retval = xpad_start_input(xpad);
-		} else if (xpad->xtype == XTYPE_XBOXONE) {
-			/*
-			 * Even if there are no users, we'll send Xbox One pads
-			 * the startup sequence so they don't sit there and
-			 * blink until somebody opens the input device again.
-			 */
-			retval = xpad_start_xbox_one(xpad);
-		}
-		mutex_unlock(&input->mutex);
+	if (xpad->xtype == XTYPE_XBOX360W)
+		return xpad360w_start_input(xpad);
+
+	guard(mutex)(&input->mutex);
+
+	if (input_device_enabled(input))
+		return xpad_start_input(xpad);
+
+	if (xpad->xtype == XTYPE_XBOXONE) {
+		/*
+		 * Even if there are no users, we'll send Xbox One pads
+		 * the startup sequence so they don't sit there and
+		 * blink until somebody opens the input device again.
+		 */
+		return xpad_start_xbox_one(xpad);
 	}
 
-	return retval;
+	return 0;
 }
 
 static struct usb_driver xpad_driver = {
-- 
2.46.0.469.g59c65b2a67-goog

Re: [PATCH 0/6] Convert joystick drivers to use new cleanup facilities

[Dmitry Torokhov]

On Tue, Sep 03, 2024 at 09:30:57PM -0700, Dmitry Torokhov wrote:
> Hi,
> 
> This series converts drivers found in drivers/input/keyboard to use new

This should have read drivers/input/joystick obviously...

> __free() and guard() cleanup facilities that simplify the code and
> ensure that all resources are released appropriately.
> 
> Thanks!
> 
> Dmitry Torokhov (6):
>   Input: db9 - use guard notation when acquiring mutex
>   Input: gamecon - use guard notation when acquiring mutex
>   Input: iforce - use guard notation when acquiring mutex and spinlock
>   Input: n64joy - use guard notation when acquiring mutex
>   Input: turbografx - use guard notation when acquiring mutex
>   Input: xpad - use guard notation when acquiring mutex and spinlock
> 
>  drivers/input/joystick/db9.c                  | 30 +++---
>  drivers/input/joystick/gamecon.c              | 22 ++---
>  drivers/input/joystick/iforce/iforce-ff.c     | 48 +++++----
>  .../input/joystick/iforce/iforce-packets.c    | 57 +++++------
>  drivers/input/joystick/iforce/iforce-serio.c  | 36 +++----
>  drivers/input/joystick/iforce/iforce-usb.c    | 13 ++-
>  drivers/input/joystick/n64joy.c               | 35 +++----
>  drivers/input/joystick/turbografx.c           | 22 ++---
>  drivers/input/joystick/xpad.c                 | 99 +++++++------------
>  9 files changed, 152 insertions(+), 210 deletions(-)
> 
> -- 
> Dmitry

-- 
Dmitry