On Tue, Jul 30, 2019 at 12:59 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:
>
> The .ioctl and .compat_ioctl file operations have the same prototype so
> they can both point to the same function, which works great almost all
> the time when all the commands are compatible.
>
> One exception is the s390 architecture, where a compat pointer is only
> 31 bit wide, and converting it into a 64-bit pointer requires calling
> compat_ptr(). Most drivers here will never run in s390, but since we now
> have a generic helper for it, it's easy enough to use it consistently.
>
> I double-checked all these drivers to ensure that all ioctl arguments
> are used as pointers or are ignored, but are not interpreted as integer
> values.
>
> Acked-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Acked-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
> Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Acked-by: David Sterba <dsterba@xxxxxxxx>
> Acked-by: Darren Hart (VMware) <dvhart@xxxxxxxxxxxxx>
> Acked-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Acked-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> drivers/nvdimm/bus.c | 4 ++--
[..]
> diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
> index 798c5c4aea9c..6ca142d833ab 100644
> --- a/drivers/nvdimm/bus.c
> +++ b/drivers/nvdimm/bus.c
> @@ -1229,7 +1229,7 @@ static const struct file_operations nvdimm_bus_fops = {
> .owner = THIS_MODULE,
> .open = nd_open,
> .unlocked_ioctl = bus_ioctl,
> - .compat_ioctl = bus_ioctl,
> + .compat_ioctl = compat_ptr_ioctl,
> .llseek = noop_llseek,
> };
>
> @@ -1237,7 +1237,7 @@ static const struct file_operations nvdimm_fops = {
> .owner = THIS_MODULE,
> .open = nd_open,
> .unlocked_ioctl = dimm_ioctl,
> - .compat_ioctl = dimm_ioctl,
> + .compat_ioctl = compat_ptr_ioctl,
> .llseek = noop_llseek,
> };
Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx>
