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Commit 8e422669 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
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USB: mutexification of usblp 



this patch:
- converts usblp fully to mutex
- makes sleeping interruptible where EINTR can be returned anyway

Signed-off-by: default avatarOliver Neukum <oliver@neukum.name>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent b1cff285

drivers/usb/class/usblp.c

+29 −25
Original line number Diff line number Diff line
@@ -130,7 +130,7 @@ MFG:HEWLETT-PACKARD;MDL:DESKJET 970C;CMD:MLC,PCL,PML;CLASS:PRINTER;DESCRIPTION:H 


struct usblp {

	struct usb_device 	*dev;			/* USB device */

	struct semaphore	sem;			/* locks this struct, especially "dev" */

	struct mutex		mut;			/* locks this struct, especially "dev" */

	char			*writebuf;		/* write transfer_buffer */

	char			*readbuf;		/* read transfer_buffer */

	char			*statusbuf;		/* status transfer_buffer */
@@ -465,7 +465,7 @@ static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	int twoints[2];

	int retval = 0;



	down (&usblp->sem);

	mutex_lock (&usblp->mut);

	if (!usblp->present) {

		retval = -ENODEV;

		goto done;
@@ -644,14 +644,14 @@ static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		}



done:

	up (&usblp->sem);

	mutex_unlock (&usblp->mut);

	return retval;

}



static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)

{

	struct usblp *usblp = file->private_data;

	int timeout, rv, err = 0, transfer_length = 0;

	int timeout, intr, rv, err = 0, transfer_length = 0;

	size_t writecount = 0;



	while (writecount < count) {
@@ -668,14 +668,16 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t 
			if (rv < 0)

				return writecount ? writecount : -EINTR;

		}

		down (&usblp->sem);

		intr = mutex_lock_interruptible (&usblp->mut);

		if (intr)

			return writecount ? writecount : -EINTR;

		if (!usblp->present) {

			up (&usblp->sem);

			mutex_unlock (&usblp->mut);

			return -ENODEV;

		}



		if (usblp->sleeping) {

			up (&usblp->sem);

			mutex_unlock (&usblp->mut);

			return writecount ? writecount : -ENODEV;

		}
@@ -687,10 +689,10 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t 
				err = usblp->writeurb->status;

			} else

				err = usblp_check_status(usblp, err);

			up (&usblp->sem);

			mutex_unlock (&usblp->mut);



			/* if the fault was due to disconnect, let khubd's

			 * call to usblp_disconnect() grab usblp->sem ...

			 * call to usblp_disconnect() grab usblp->mut ...

			 */

			schedule ();

			continue;
@@ -702,7 +704,7 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t 
		 */

		writecount += transfer_length;

		if (writecount == count) {

			up(&usblp->sem);

			mutex_unlock(&usblp->mut);

			break;

		}
@@ -714,7 +716,7 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t 


		if (copy_from_user(usblp->writeurb->transfer_buffer, 

				   buffer + writecount, transfer_length)) {

			up(&usblp->sem);

			mutex_unlock(&usblp->mut);

			return writecount ? writecount : -EFAULT;

		}
@@ -727,10 +729,10 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t 
				count = -EIO;

			else

				count = writecount ? writecount : -ENOMEM;

			up (&usblp->sem);

			mutex_unlock (&usblp->mut);

			break;

		}

		up (&usblp->sem);

		mutex_unlock (&usblp->mut);

	}



	return count;
@@ -739,12 +741,14 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t 
static ssize_t usblp_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)

{

	struct usblp *usblp = file->private_data;

	int rv;

	int rv, intr;



	if (!usblp->bidir)

		return -EINVAL;



	down (&usblp->sem);

	intr = mutex_lock_interruptible (&usblp->mut);

	if (intr)

		return -EINTR;

	if (!usblp->present) {

		count = -ENODEV;

		goto done;
@@ -757,9 +761,9 @@ static ssize_t usblp_read(struct file *file, char __user *buffer, size_t count, 
			count = -EAGAIN;

			goto done;

		}

		up(&usblp->sem);

		mutex_unlock(&usblp->mut);

		rv = wait_event_interruptible(usblp->wait, usblp->rcomplete || !usblp->present);

		down(&usblp->sem);

		mutex_lock(&usblp->mut);

		if (rv < 0) {

			count = -EINTR;

			goto done;
@@ -807,7 +811,7 @@ static ssize_t usblp_read(struct file *file, char __user *buffer, size_t count, 
	}



done:

	up (&usblp->sem);

	mutex_unlock (&usblp->mut);

	return count;

}
@@ -886,7 +890,7 @@ static int usblp_probe(struct usb_interface *intf, 
		goto abort;

	}

	usblp->dev = dev;

	init_MUTEX (&usblp->sem);

	mutex_init (&usblp->mut);

	init_waitqueue_head(&usblp->wait);

	usblp->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;

	usblp->intf = intf;
@@ -1178,7 +1182,7 @@ static void usblp_disconnect(struct usb_interface *intf) 
	device_remove_file(&intf->dev, &dev_attr_ieee1284_id);



	mutex_lock (&usblp_mutex);

	down (&usblp->sem);

	mutex_lock (&usblp->mut);

	usblp->present = 0;

	usb_set_intfdata (intf, NULL);
@@ -1187,7 +1191,7 @@ static void usblp_disconnect(struct usb_interface *intf) 
			usblp->writebuf, usblp->writeurb->transfer_dma);

	usb_buffer_free (usblp->dev, USBLP_BUF_SIZE,

			usblp->readbuf, usblp->readurb->transfer_dma);

	up (&usblp->sem);

	mutex_unlock (&usblp->mut);



	if (!usblp->used)

		usblp_cleanup (usblp);
@@ -1200,11 +1204,11 @@ static int usblp_suspend (struct usb_interface *intf, pm_message_t message) 


	/* this races against normal access and open */

	mutex_lock (&usblp_mutex);

	down (&usblp->sem);

	mutex_lock (&usblp->mut);

	/* we take no more IO */

	usblp->sleeping = 1;

	usblp_unlink_urbs(usblp);

	up (&usblp->sem);

	mutex_unlock (&usblp->mut);

	mutex_unlock (&usblp_mutex);



	return 0;
@@ -1216,12 +1220,12 @@ static int usblp_resume (struct usb_interface *intf) 
	int r;



	mutex_lock (&usblp_mutex);

	down (&usblp->sem);

	mutex_lock (&usblp->mut);



	usblp->sleeping = 0;

	r = handle_bidir (usblp);



	up (&usblp->sem);

	mutex_unlock (&usblp->mut);

	mutex_unlock (&usblp_mutex);



	return r;