From 8cca0235839100bcc95803b1cd7341b2d2b8fe21 Mon Sep 17 00:00:00 2001
From: Myron Stowe <mstowe@redhat.com>
Date: Tue, 25 Mar 2025 12:19:58 -0600
Subject: [PATCH] PCI: Fix BUILD_BUG_ON usage for old gcc
JIRA: https://issues.redhat.com/browse/RHEL-83611
Upstream Status: 472ff48e2c09e49f2f90eeb6922f747306559506
commit 472ff48e2c09e49f2f90eeb6922f747306559506
Author: Alex Williamson <alex.williamson@redhat.com>
Date: Wed Feb 12 11:53:32 2025 -0700
PCI: Fix BUILD_BUG_ON usage for old gcc
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.
Link: https://lore.kernel.org/r/20250212185337.293023-1-alex.williamson@redhat.com
Fixes: 4453f360862e ("PCI: Batch BAR sizing operations")
Reported-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/all/20250209154512.GA18688@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Mitchell Augustin <mitchell.augustin@canonical.com>
Signed-off-by: Myron Stowe <mstowe@redhat.com>
---
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 e66cfca1e259b..f7430956a6018 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;
--
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