| Message ID | 20250212185337.293023-1-alex.williamson@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 472ff48e2c09e49f2f90eeb6922f747306559506 |
| Headers | show |
| Series | [v2] PCI: Fix BUILD_BUG_ON usage for old gcc | expand |
On Wed, Feb 12, 2025 at 11:53:32AM -0700, Alex Williamson wrote: > As reported in the below link, it seems older versions of gcc cannot > determine that the howmany variable is known for all callers. Include > a test so that newer compilers can enforce this sanity check and older > compilers can still work. Add __always_inline attribute to give the > compiler an even better chance to know the inputs. > > Fixes: 4453f360862e ("PCI: Batch BAR sizing operations") > Link: https://lore.kernel.org/all/20250209154512.GA18688@redhat.com > Reported-by: Oleg Nesterov <oleg@redhat.com> > Tested-by: Oleg Nesterov <oleg@redhat.com> > Tested-by: Mitchell Augustin <mitchell.augustin@canonical.com> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Applied to pci/for-linus for v6.14 since this fixes a build issue we added in v6.14-rc1, thanks, Alex. > --- > > v2: > - Switch to statically_true (David Laight) > - Add __always_inline (David Laight) > - Included Tested-by reports > > drivers/pci/probe.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index b6536ed599c3..246744d8d268 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -339,13 +339,14 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, > return (res->flags & IORESOURCE_MEM_64) ? 1 : 0; > } > > -static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom) > +static __always_inline void pci_read_bases(struct pci_dev *dev, > + unsigned int howmany, int rom) > { > u32 rombar, stdbars[PCI_STD_NUM_BARS]; > unsigned int pos, reg; > u16 orig_cmd; > > - BUILD_BUG_ON(howmany > PCI_STD_NUM_BARS); > + BUILD_BUG_ON(statically_true(howmany > PCI_STD_NUM_BARS)); > > if (dev->non_compliant_bars) > return; > -- > 2.48.1 >
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index b6536ed599c3..246744d8d268 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -339,13 +339,14 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, return (res->flags & IORESOURCE_MEM_64) ? 1 : 0; } -static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom) +static __always_inline void pci_read_bases(struct pci_dev *dev, + unsigned int howmany, int rom) { u32 rombar, stdbars[PCI_STD_NUM_BARS]; unsigned int pos, reg; u16 orig_cmd; - BUILD_BUG_ON(howmany > PCI_STD_NUM_BARS); + BUILD_BUG_ON(statically_true(howmany > PCI_STD_NUM_BARS)); if (dev->non_compliant_bars) return;
As reported in the below link, it seems older versions of gcc cannot determine that the howmany variable is known for all callers. Include a test so that newer compilers can enforce this sanity check and older compilers can still work. Add __always_inline attribute to give the compiler an even better chance to know the inputs. Fixes: 4453f360862e ("PCI: Batch BAR sizing operations") Link: https://lore.kernel.org/all/20250209154512.GA18688@redhat.com Reported-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Mitchell Augustin <mitchell.augustin@canonical.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> --- v2: - Switch to statically_true (David Laight) - Add __always_inline (David Laight) - Included Tested-by reports drivers/pci/probe.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)