USB: mutexification of usblp
this patch:
- converts usblp fully to mutex
- makes sleeping interruptible where EINTR can be returned anyway
Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index 6303970..24ee8be 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -130,7 +130,7 @@
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 @@
int twoints[2];
int retval = 0;
- down (&usblp->sem);
+ mutex_lock (&usblp->mut);
if (!usblp->present) {
retval = -ENODEV;
goto done;
@@ -644,14 +644,14 @@
}
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 @@
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 @@
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 @@
*/
writecount += transfer_length;
if (writecount == count) {
- up(&usblp->sem);
+ mutex_unlock(&usblp->mut);
break;
}
@@ -714,7 +716,7 @@
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 @@
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_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 @@
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 @@
}
done:
- up (&usblp->sem);
+ mutex_unlock (&usblp->mut);
return count;
}
@@ -886,7 +890,7 @@
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 @@
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 @@
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 @@
/* 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 @@
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;