[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>

1 files changed, 24 insertions, 47 deletions

diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index dba4cc026077..d34848ac30b0 100644
--- 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;
 }