Hi Jonathan, On Mon, Feb 12, 2024 at 11:42:06AM +0000, Jonathan Cameron wrote: > On Mon, 12 Feb 2024 08:49:23 +0000 > Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> wrote: > > > Hi Jonathan, > > > > On Sun, Feb 11, 2024 at 07:25:27PM +0000, Jonathan Cameron wrote: > > > From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > > > > > Useful where the fwnode_handle was obtained from a call such as > > > fwnode_find_reference() as it will safely do nothing if IS_ERR() is true > > > and will automatically release the reference on the variable leaving > > > scope. > > > > > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > > --- > > > include/linux/property.h | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/include/linux/property.h b/include/linux/property.h > > > index e6516d0b7d52..bcda028f1a33 100644 > > > --- a/include/linux/property.h > > > +++ b/include/linux/property.h > > > @@ -12,6 +12,7 @@ > > > > > > #include <linux/args.h> > > > #include <linux/bits.h> > > > +#include <linux/cleanup.h> > > > #include <linux/fwnode.h> > > > #include <linux/stddef.h> > > > #include <linux/types.h> > > > @@ -188,6 +189,8 @@ struct fwnode_handle *device_get_named_child_node(const struct device *dev, > > > > > > struct fwnode_handle *fwnode_handle_get(struct fwnode_handle *fwnode); > > > void fwnode_handle_put(struct fwnode_handle *fwnode); > > > +DEFINE_FREE(fwnode_handle, struct fwnode_handle *, > > > + if (!IS_ERR_OR_NULL(_T)) fwnode_handle_put(_T)) > > > > fwnode_handle_put() can be safely called on NULL or error pointer fwnode so > > you can remove the check. > > Was discussed in the RFC thread (where i didn't have this protection) > > https://lore.kernel.org/linux-iio/20240108125117.000010fb@xxxxxxxxxx/ > includes a reference to Linus Torvald's view on this. > > All comes down to compiler visibility and optimization opportunities, which are improved > if the check is in the macro definition. Hmm. In that case I'd rather make fwnode_handle_put() and similar trivial functions macros. There's no need to add cruft here and about a 100-fold number of callers will get the same benefit. -- Sakari Ailus
