Re: [PATCH 11/12] vfio/mdev: Use the driver core to create the 'remove' file

From: Jason Gunthorpe <jgg@nvidia.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	kvm@vger.kernel.org, Kirti Wankhede <kwankhede@nvidia.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Daniel Vetter <daniel@ffwll.ch>,
	Leon Romanovsky <leonro@nvidia.com>,
	Max Gurtovoy <mgurtovoy@nvidia.com>,
	Tarun Gupta <targupta@nvidia.com>
Subject: Re: [PATCH 11/12] vfio/mdev: Use the driver core to create the 'remove' file
Date: Mon, 26 Apr 2021 16:07:24 -0300	[thread overview]
Message-ID: <20210426190724.GA1370958@nvidia.com> (raw)
In-Reply-To: <20210426142011.GI15209@lst.de>

On Mon, Apr 26, 2021 at 04:20:11PM +0200, Christoph Hellwig wrote:
> > diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
> > index 5a3873d1a275ae..0ccfeb3dda2455 100644
> > +++ b/drivers/vfio/mdev/mdev_sysfs.c
> > @@ -244,11 +244,20 @@ static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
> >  
> >  static DEVICE_ATTR_WO(remove);
> >  
> > -static const struct attribute *mdev_device_attrs[] = {
> > +static struct attribute *mdev_device_attrs[] = {
> 
> Why does this lose the const?

Due to the way the driver core sets up it structs:

drivers/vfio/mdev/mdev_sysfs.c:273:11: error: initialization of ‘struct attribute **’ from incompatible pointer type ‘const struct attribute **’ [-Werror=incompatible-pointer-types]
  273 |  .attrs = mdev_device_attrs,

struct attribute_group {
[..]
	struct attribute	**attrs;

Thanks,
Jason