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Commit efd61e94 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Greg Kroah-Hartman
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usb: iowarrior: remove intr_idx_lock 



The intr_idx_lock lock is acquired only in the completion callback of
the ->int_in_urb (iowarrior_callback()). There is only one URB that is
scheduled / completed so there can't be more than one user of the lock.
The comment says that it protects ->intr_idx and the callback is the
only place in driver that writes to it.

Remove the intr_idx_lock lock because it is superfluous.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 957ada71

drivers/usb/misc/iowarrior.c

+0 −5
Original line number Diff line number Diff line
@@ -81,7 +81,6 @@ struct iowarrior { 
	atomic_t write_busy;		/* number of write-urbs submitted */

	atomic_t read_idx;

	atomic_t intr_idx;

	spinlock_t intr_idx_lock;	/* protects intr_idx */

	atomic_t overflow_flag;		/* signals an index 'rollover' */

	int present;			/* this is 1 as long as the device is connected */

	int opened;			/* this is 1 if the device is currently open */
@@ -166,7 +165,6 @@ static void iowarrior_callback(struct urb *urb) 
		goto exit;

	}



	spin_lock(&dev->intr_idx_lock);

	intr_idx = atomic_read(&dev->intr_idx);

	/* aux_idx become previous intr_idx */

	aux_idx = (intr_idx == 0) ? (MAX_INTERRUPT_BUFFER - 1) : (intr_idx - 1);
@@ -181,7 +179,6 @@ static void iowarrior_callback(struct urb *urb) 
		    (dev->read_queue + offset, urb->transfer_buffer,

		     dev->report_size)) {

			/* equal values on interface 0 will be ignored */

			spin_unlock(&dev->intr_idx_lock);

			goto exit;

		}

	}
@@ -202,7 +199,6 @@ static void iowarrior_callback(struct urb *urb) 
	*(dev->read_queue + offset + (dev->report_size)) = dev->serial_number++;



	atomic_set(&dev->intr_idx, aux_idx);

	spin_unlock(&dev->intr_idx_lock);

	/* tell the blocking read about the new data */

	wake_up_interruptible(&dev->read_wait);
@@ -762,7 +758,6 @@ static int iowarrior_probe(struct usb_interface *interface, 


	atomic_set(&dev->intr_idx, 0);

	atomic_set(&dev->read_idx, 0);

	spin_lock_init(&dev->intr_idx_lock);

	atomic_set(&dev->overflow_flag, 0);

	init_waitqueue_head(&dev->read_wait);

	atomic_set(&dev->write_busy, 0);