Re: [PATCH] deprecate (un)register_ioctl32_conversion

[Michael S. Tsirkin]

Hello!
Quoting r. Christoph Hellwig (hch@xxxxxxxxxxxxx) "Re: [PATCH] deprecate (un)register_ioctl32_conversion":
> > Stare at this as I might, I dont understand why does it make sence.
> > So if filp->f_op is NULL, you are then checking filp->f_op->ioctl?
> > Looks like an oops to me.
> 
> I doesn't make sense, but fortunately files with NULL filp->f_op don't
> happen in practice (need to research whether it can't happen in theory
> either so we could lose lots of checks)

Interesting. At least for character devices coming out of modules I think you
dont - you need at least fops->owner.

> --- linux-2.6.10-mm2.orig/fs/compat.c	2005-01-06 11:40:18.831900000 +0100
> +++ linux-2.6.10-mm2/fs/compat.c	2005-01-06 15:50:23.802874672 +0100
> @@ -436,10 +436,10 @@
>  	if (!filp)
>  		goto out;
>  
> -	if (!filp->f_op) {
> -		if (!filp->f_op->ioctl)
> -			goto do_ioctl;
> -	} else if (filp->f_op->compat_ioctl) {
> +	if (!filp->f_op || !filp->f_op->ioctl)
> +		goto do_ioctl;
> +
> +	if (filp->f_op || filp->f_op->compat_ioctl) {
>  		error = filp->f_op->compat_ioctl(filp, cmd, arg);
>  		goto out_fput;
>  	}

So now if I dont have ->ioctl the ioctl_compat wont be called.
What if I only have unlocked_ioctl?

MST
-
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