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 (file)
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -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;