linux-kernel - [tip: irq/urgent] PCI/MSI: Remove bogus warning in pci_irq_get

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Message-ID: <164396506527.16921.1990922190197899743.tip-bot2@tip-bot2>
Date:   Fri, 04 Feb 2022 08:57:45 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Guenter Roeck <linux@...ck-us.net>,
        Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org, maz@...nel.org
Subject: [tip: irq/urgent] PCI/MSI: Remove bogus warning in pci_irq_get_affinity()

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@...utronix.de>
AuthorDate:    Mon, 31 Jan 2022 22:02:46 +01:00
Committer:     Thomas Gleixner <tglx@...utronix.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@...ck-us.net>
Signed-off-by: Thomas Gleixner <tglx@...utronix.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;

 	/*