[tip: irq/urgent] PCI/MSI: Remove bogus warning in pci_irq_get_affinity()

tip-bot2 for Thomas Gleixner
2022-02-04T08:57:49Z

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID: dd7f5a11ac5a6f733f422dc22b4d145d3260304e
Gitweb: https://git.kernel.org/tip/dd7f5a11ac5a6f733f422dc22b4d145d3260304e
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 31 Jan 2022 22:02:46 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 04 Feb 2022 09:54:20 +01:00

PCI/MSI: Remove bogus warning in pci_irq_get_affinity()

The recent overhaul of pci_irq_get_affinity() introduced a regression when
pci_irq_get_affinity() is called for an MSI-X interrupt which was not
allocated with affinity descriptor information.

The original code just returned a NULL pointer in that case, but the rework
added a WARN_ON() under the assumption that the corresponding WARN_ON() in
the MSI case can be applied to MSI-X as well.

In fact the MSI warning in the original code does not make sense either
because it's legitimate to invoke pci_irq_get_affinity() for a MSI
interrupt which was not allocated with affinity descriptor information.

Remove it and just return NULL as the original code did.

Fixes: f48235900182 ("PCI/MSI: Simplify pci_irq_get_affinity()")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/87ee4n38sm.ffs@tglx

---
drivers/pci/msi/msi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index c19c7ca..9037a78 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -1111,7 +1111,8 @@ const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
if (!desc)
return cpu_possible_mask;

- if (WARN_ON_ONCE(!desc->affinity))
+ /* MSI[X] interrupts can be allocated without affinity descriptor */
+ if (!desc->affinity)
return NULL;

/*