El Tue, Apr 11, 2017 at 12:08:38PM +0200 Mason ha dit: > On 11/04/2017 03:24, Bjorn Helgaas wrote: > > > On Mon, Apr 10, 2017 at 03:24:57PM -0700, Matthias Kaehlcke wrote: > > > >> This fixes a clang warning about "implicit conversion from 'unsigned > >> long' to 'u32'" > >> > >> Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > >> --- > >> drivers/pci/probe.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > >> index dfc9a2794141..148e80d5caf1 100644 > >> --- a/drivers/pci/probe.c > >> +++ b/drivers/pci/probe.c > >> @@ -180,7 +180,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, > >> u16 orig_cmd; > >> struct pci_bus_region region, inverted_region; > >> > >> - mask = type ? PCI_ROM_ADDRESS_MASK : ~0; > >> + mask = type ? (u32)PCI_ROM_ADDRESS_MASK : ~0; > > > > Can we put the cast in the PCI_ROM_ADDRESS_MASK #define so we don't have to > > repeat it in all the uses? > > Fixing these "implicit conversion" warnings, especially for > unsigned types, is a slippery slope. (The behavior of the > conversion is well-defined.) > > How about changing the type of PCI_ROM_ADDRESS_MASK instead? > It's defined as ~0x7ffUL but it's only used in the context > of u32. > > So make it an unsigned int: > #define PCI_ROM_ADDRESS_MASK (~0x7ffU) > > AFAIU, unsigned int is 32 bits on all platforms supported > by Linux. I considered this initially, but wasn't sure if the unsigned long mask might be needed in some cases. From the comments I interpret that there should be no problems with using a 32 bit mask everywhere. I'll send out an updated patch shortly. Thanks Matthias
