[PATCH] USB: cleanup of usblp

this fixes
-potential hang by disconnecting through usbfs
-kzalloc
-general cleanup
-micro optimisation in interrupt handlers

It compiles and I am printing.

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 dba4cc0260770ebf8d6c39963cd8345c80a98b2a..d34848ac30b0a9571db2dd6cd596cdf139b5c8df 100644 (file)
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -7,6 +7,7 @@
  * Copyright (c) 2000 Vojtech Pavlik   <vojtech@suse.cz>
  # Copyright (c) 2001 Pete Zaitcev     <zaitcev@redhat.com>
  # Copyright (c) 2001 David Paschal    <paschal@rcsis.com>
+ * Copyright (c) 2006 Oliver Neukum    <oliver@neukum.name>
  *
  * USB Printer Device Class driver for USB printers and printer cables
  *
@@ -273,13 +274,16 @@ static void usblp_bulk_read(struct urb *urb, struct pt_regs *regs)
 {
        struct usblp *usblp = urb->context;
 
-       if (!usblp || !usblp->dev || !usblp->used || !usblp->present)
+       if (unlikely(!usblp || !usblp->dev || !usblp->used))
                return;
 
+       if (unlikely(!usblp->present))
+               goto unplug;
        if (unlikely(urb->status))
                warn("usblp%d: nonzero read/write bulk status received: %d",
                        usblp->minor, urb->status);
        usblp->rcomplete = 1;
+unplug:
        wake_up_interruptible(&usblp->wait);
 }
 
@@ -287,13 +291,15 @@ static void usblp_bulk_write(struct urb *urb, struct pt_regs *regs)
 {
        struct usblp *usblp = urb->context;
 
-       if (!usblp || !usblp->dev || !usblp->used || !usblp->present)
+       if (unlikely(!usblp || !usblp->dev || !usblp->used))
                return;
-
+       if (unlikely(!usblp->present))
+               goto unplug;
        if (unlikely(urb->status))
                warn("usblp%d: nonzero read/write bulk status received: %d",
                        usblp->minor, urb->status);
        usblp->wcomplete = 1;
+unplug:
        wake_up_interruptible(&usblp->wait);
 }
 
@@ -627,9 +633,8 @@ done:
 
 static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 {
-       DECLARE_WAITQUEUE(wait, current);
        struct usblp *usblp = file->private_data;
-       int timeout, err = 0, transfer_length = 0;
+       int timeout, rv, err = 0, transfer_length = 0;
        size_t writecount = 0;
 
        while (writecount < count) {
@@ -641,24 +646,11 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t
                        }
 
                        timeout = USBLP_WRITE_TIMEOUT;
-                       add_wait_queue(&usblp->wait, &wait);
-                       while ( 1==1 ) {
 
-                               if (signal_pending(current)) {
-                                       remove_wait_queue(&usblp->wait, &wait);
-                                       return writecount ? writecount : -EINTR;
-                               }
-                               set_current_state(TASK_INTERRUPTIBLE);
-                               if (timeout && !usblp->wcomplete) {
-                                       timeout = schedule_timeout(timeout);
-                               } else {
-                                       set_current_state(TASK_RUNNING);
-                                       break;
-                               }
-                       }
-                       remove_wait_queue(&usblp->wait, &wait);
+                       rv = wait_event_interruptible_timeout(usblp->wait, usblp->wcomplete || !usblp->present , timeout);
+                       if (rv < 0)
+                               return writecount ? writecount : -EINTR;
                }
-
                down (&usblp->sem);
                if (!usblp->present) {
                        up (&usblp->sem);
@@ -724,7 +716,7 @@ 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;
-       DECLARE_WAITQUEUE(wait, current);
+       int rv;
 
        if (!usblp->bidir)
                return -EINVAL;
@@ -742,26 +734,13 @@ static ssize_t usblp_read(struct file *file, char __user *buffer, size_t count,
                        count = -EAGAIN;
                        goto done;
                }
-
-               add_wait_queue(&usblp->wait, &wait);
-               while (1==1) {
-                       if (signal_pending(current)) {
-                               count = -EINTR;
-                               remove_wait_queue(&usblp->wait, &wait);
-                               goto done;
-                       }
-                       up (&usblp->sem);
-                       set_current_state(TASK_INTERRUPTIBLE);
-                       if (!usblp->rcomplete) {
-                               schedule();
-                       } else {
-                               set_current_state(TASK_RUNNING);
-                               down(&usblp->sem);
-                               break;
-                       }
-                       down (&usblp->sem);
+               up(&usblp->sem);
+               rv = wait_event_interruptible(usblp->wait, usblp->rcomplete || !usblp->present);
+               down(&usblp->sem);
+               if (rv < 0) {
+                       count = -EINTR;
+                       goto done;
                }
-               remove_wait_queue(&usblp->wait, &wait);
        }
 
        if (!usblp->present) {
@@ -874,11 +853,10 @@ static int usblp_probe(struct usb_interface *intf,
 
        /* Malloc and start initializing usblp structure so we can use it
         * directly. */
-       if (!(usblp = kmalloc(sizeof(struct usblp), GFP_KERNEL))) {
+       if (!(usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL))) {
                err("out of memory for usblp");
                goto abort;
        }
-       memset(usblp, 0, sizeof(struct usblp));
        usblp->dev = dev;
        init_MUTEX (&usblp->sem);
        init_waitqueue_head(&usblp->wait);
@@ -1214,10 +1192,9 @@ static int __init usblp_init(void)
 {
        int retval;
        retval = usb_register(&usblp_driver);
-       if (retval)
-               goto out;
-       info(DRIVER_VERSION ": " DRIVER_DESC);
-out:
+       if (!retval)
+               info(DRIVER_VERSION ": " DRIVER_DESC);
+
        return retval;
 }