On Sun, Oct 09, 2016 at 10:49:05AM -0600, Jason Gunthorpe wrote: > On Sun, Oct 09, 2016 at 12:38:18PM +0300, Jarkko Sakkinen wrote: > > On Sat, Oct 08, 2016 at 07:42:56PM -0600, Jason Gunthorpe wrote: > > > On Sun, Oct 09, 2016 at 03:15:09AM +0300, Jarkko Sakkinen wrote: > > > > + ctrl = crb_map_res(dev, priv, &io_res, buf->control_address, > > > > + sizeof(struct crb_regs) - > > > > + offsetof(struct crb_regs, ctrl_req)); > > > > + if (IS_ERR(ctrl)) > > > > + return PTR_ERR(ctrl); > > > > + > > > > + /* The control area always overrlaps IO memory mapped from the > > > > ACPI > > > > + * object with CRB start only devices. Thus, this is perfectly > > > > safe. > > > > + */ > > > > + priv->regs = (void *)((unsigned long)ctrl - > > > > + offsetof(struct crb_regs, ctrl_req)); > > > > > > Hum. No, this makes bad assumptions about the structure of iomapping. > > > > > > The map itself needs to be done with the adjustment: > > > > > > ctrl = crb_map_res(dev, priv, &io_res, buf->control_address - > > > offsetof(struct crb_regs, ctrl_req), > > > sizeof(struct crb_regs)); > > > > That would be wrong address for the control area as it does not start > > from the beginning of CRB registers. > > Of course, I just pointed out what the map call should look like > > Something like this > > priv->regs = crb_map_res(dev, priv, &io_res, buf->control_address - > offsetof(struct crb_regs, ctrl_req), > sizeof(struct crb_regs)); > ctrl = &priv->regs.ctrl_req; > > > I think the crb_map_io and crb_map_res are too generic. Better way to do > > things would be to validate that assumptions for these two cases hold. > > If the driver is going to be using a negative offset like this, then > it very much should validate the assumptions before doing it. > > and not even map these regsiters if they are not supported by > hardware.
Yes, that's what the point I tried to make in my response in the part that is not quoted here. /Jarkko
