Re: [PATCH] Change paride driver to use unlocked_ioctl instead ofioctl

From: Nikanth Karthikesan
Date: Thu Jan 10 2008 - 00:25:51 EST


On Wed, 2008-01-09 at 16:56 +0000, Alan Cox wrote:
> On Wed, 9 Jan 2008 14:26:26 +0100 (CET)
> Jiri Kosina <jikos@xxxxxxxx> wrote:
>
> > On Wed, 9 Jan 2008, Matthew Wilcox wrote:
> >
> > > > default:
> > > > printk("%s: Unimplemented ioctl 0x%x\n", tape->name, cmd);
> > > > + unlock_kernel();
> > > > return -EINVAL;
> > > Surely a bug ... shouldn't this return -ENOTTY?
>
> Agreed - ENOTTY. The printk is wrong as well, but this is just getting
> shown up by the other changes.
>
> Does anyone even use parallel IDE devices any more ?

Resending the patch. Also made the locks a little tighter, but I am not
sure whether the locks are required.

The ioctl handler is called with the BKL held. Registering
unlocked_ioctl handler instead of registering ioctl handler.
Also changed the return value to -ENOTTY for invalid ioctls.

Signed-off-by: Nikanth Karthikesan <knikanth@xxxxxxx>

---


diff --git a/drivers/block/paride/pt.c b/drivers/block/paride/pt.c
index b91accf..b7215fa 100644
--- a/drivers/block/paride/pt.c
+++ b/drivers/block/paride/pt.c
@@ -146,6 +146,7 @@ static int (*drives[4])[6] = {&drive0, &drive1, &drive2, &drive3};
#include <linux/mtio.h>
#include <linux/device.h>
#include <linux/sched.h> /* current, TASK_*, schedule_timeout() */
+#include <linux/smp_lock.h>

#include <asm/uaccess.h>

@@ -189,8 +190,8 @@ module_param_array(drive3, int, NULL, 0);
#define ATAPI_LOG_SENSE 0x4d

static int pt_open(struct inode *inode, struct file *file);
-static int pt_ioctl(struct inode *inode, struct file *file,
- unsigned int cmd, unsigned long arg);
+static long pt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg);
static int pt_release(struct inode *inode, struct file *file);
static ssize_t pt_read(struct file *filp, char __user *buf,
size_t count, loff_t * ppos);
@@ -236,7 +237,7 @@ static const struct file_operations pt_fops = {
.owner = THIS_MODULE,
.read = pt_read,
.write = pt_write,
- .ioctl = pt_ioctl,
+ .unlocked_ioctl = pt_ioctl,
.open = pt_open,
.release = pt_release,
};
@@ -685,8 +686,8 @@ out:
return err;
}

-static int pt_ioctl(struct inode *inode, struct file *file,
- unsigned int cmd, unsigned long arg)
+static long pt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
{
struct pt_unit *tape = file->private_data;
struct mtop __user *p = (void __user *)arg;
@@ -700,11 +701,15 @@ static int pt_ioctl(struct inode *inode, struct file *file,
switch (mtop.mt_op) {

case MTREW:
+ lock_kernel();
pt_rewind(tape);
+ unlock_kernel();
return 0;

case MTWEOF:
+ lock_kernel();
pt_write_fm(tape);
+ unlock_kernel();
return 0;

default:
@@ -714,8 +719,8 @@ static int pt_ioctl(struct inode *inode, struct file *file,
}

default:
- printk("%s: Unimplemented ioctl 0x%x\n", tape->name, cmd);
- return -EINVAL;
+ printk("%s: Invalid ioctl 0x%x\n", tape->name, cmd);
+ return -ENOTTY;

}
}


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