On Thu, Mar 23, 2023 at 04:38:29PM +0200, Andy Shevchenko wrote: > On Thu, Mar 23, 2023 at 02:31:04PM +0000, Russell King (Oracle) wrote: > > On Thu, Mar 23, 2023 at 04:03:05PM +0200, Andy Shevchenko wrote: > > > On Wed, Mar 22, 2023 at 12:00:06PM +0000, Russell King (Oracle) wrote: > > ... > > > > > + struct fwnode_handle *fwnode; > > > > > > > + fwnode = of_fwnode_handle(dp->dn); > > > > > > const struct fwnode_handle *fwnode = of_fwnode_handle(dp->dn); > > > > > > ? > > > > Why const? > > Do you modify its content on the fly? Do you want to litter code with casts to get rid of the const? > For fwnode as a basic object type we want to reduce the scope of the possible > modifications. If you don't modify and APIs you call do not require non-const > object, use const for fwnode. Let's start here. We pass this fwnode to fwnode_get_phy_mode(): include/linux/property.h:int fwnode_get_phy_mode(struct fwnode_handle *fwnode); Does fwnode_get_phy_mode() alter the contents of the fwnode? Probably not, but it doesn't take a const pointer. Therefore, to declare my fwnode as const, I'd need to cast the const-ness away before calling this. Then there's phylink_create(). Same problem. So NAK to this const - until such time that we have a concerted effort to making functions we call which do not modify the "fwnode" argument constify that argument. Otherwise it's just rediculously crazy to declare a variable const only to then litter the code with casts to get rid of it at every call site. Please do a bit of research before making suggestions. Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
