[PATCH] usblcd: Push down BKL into driver

[PATCH] usblcd: Push down BKL into driver

[Alan Cox]

I'm pretty sure this can be eliminated however I couldn't prove (or find)
what stopped the device vanishing mid IOCTL_GET_HARD_VERSION. Perhaps a
USB wizard could double check that and see if the lock_kernel can go
entirely.

Signed-off-by: Alan Cox <alan@redhat.com>

diff --git a/drivers/usb/misc/usblcd.c b/drivers/usb/misc/usblcd.c
index 7f7021e..2db4228 100644
--- a/drivers/usb/misc/usblcd.c
+++ b/drivers/usb/misc/usblcd.c
@@ -146,7 +146,7 @@ static ssize_t lcd_read(struct file *file, char __user * buffer, size_t count, l
 	return retval;
 }
 
-static int lcd_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
+static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct usb_lcd *dev;
 	u16 bcdDevice;
@@ -158,12 +158,14 @@ static int lcd_ioctl(struct inode *inode, struct file *file, unsigned int cmd, u
 	
 	switch (cmd) {
 	case IOCTL_GET_HARD_VERSION:
+		lock_kernel();
 		bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
 		sprintf(buf,"%1d%1d.%1d%1d",
 			(bcdDevice & 0xF000)>>12,
 			(bcdDevice & 0xF00)>>8,
 			(bcdDevice & 0xF0)>>4,
 			(bcdDevice & 0xF));
+		unlock_kernel();
 		if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
 			return -EFAULT;
 		break;
@@ -272,7 +274,7 @@ static const struct file_operations lcd_fops = {
         .read =         lcd_read,
         .write =        lcd_write,
         .open =         lcd_open,
-	.ioctl =        lcd_ioctl,
+	.unlocked_ioctl = lcd_ioctl,
         .release =      lcd_release,
 };
 

Re: [PATCH] usblcd: Push down BKL into driver

[Oliver Neukum]

Am Donnerstag 22 Mai 2008 23:07:51 schrieb Alan Cox:
> I'm pretty sure this can be eliminated however I couldn't prove (or find)
> what stopped the device vanishing mid IOCTL_GET_HARD_VERSION. Perhaps a
> USB wizard could double check that and see if the lock_kernel can go
> entirely.

Nothing does. The driver is buggy as it is now irrespective of BKL.
Thanks for noticing.

	Regards
		Oliver