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usb: iowarrior: remove intr_idx_lock

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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: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sebastian Andrzej Siewior 2018-06-25 00:08:43 +02:00 committed by Greg Kroah-Hartman
parent 957ada71b6
commit efd61e94fa
1 changed files with 0 additions and 5 deletions
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5
drivers/usb/misc/iowarrior.c
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@ -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);