FAILED: patch "[PATCH] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Aug 16, 2021

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Stable branch IRQ

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2021-08-16 08:03 UTC #0 lore raw

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 826da771291fc25a428e871f9e7fb465e390f852 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <[email protected]>
Date: Thu, 29 Jul 2021 23:51:48 +0200
Subject: [PATCH] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP

X86 IO/APIC and MSI interrupts (when used without interrupts remapping) require that the affinity setup on startup is done before the interrupt is enabled for the first time as the non-remapped operation mode cannot safely migrate enabled interrupts from arbitrary contexts. Provide a new irq chip flag which allows affected hardware to request this.

This has to be opt-in because there have been reports in the past that some interrupt chips cannot handle affinity setting before startup.

Fixes 18404756765c ("genirq: Expose default irq affinity mask (take 3)")

Signed-off-by Thomas Gleixner <[email protected]>

Tested-by Marc Zyngier <[email protected]>

Reviewed-by Marc Zyngier <[email protected]>

Cc [email protected]

Link https://lore.kernel.org/r/[email protected] open here

include/linux/irq.h +2 -0

index 8e9a9ae471a6..c8293c817646 100644
@@ -569,6 +569,7 @@ struct irq_chip {
  * IRQCHIP_SUPPORTS_NMI:              Chip can deliver NMIs, only for root irqchips
  * IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND:  Invokes __enable_irq()/__disable_irq() for wake irqs
  *                                    in the suspend path if they are in disabled state
+ * IRQCHIP_AFFINITY_PRE_STARTUP:      Default affinity update before startup
  */
 enum {
 	IRQCHIP_SET_TYPE_MASKED			= (1 <<  0),

@@ -581,6 +582,7 @@ enum {
 	IRQCHIP_SUPPORTS_LEVEL_MSI		= (1 <<  7),
 	IRQCHIP_SUPPORTS_NMI			= (1 <<  8),
 	IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND	= (1 <<  9),
+	IRQCHIP_AFFINITY_PRE_STARTUP		= (1 << 10),
 };
 
 #include <linux/irqdesc.h>

kernel/irq/chip.c +4 -1

index 7f04c7d8296e..a98bcfc4be7b 100644
@@ -265,8 +265,11 @@ int irq_startup(struct irq_desc *desc, bool resend, bool force)
 	} else {
 		switch (__irq_startup_managed(desc, aff, force)) {
 		case IRQ_STARTUP_NORMAL:
+			if (d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP)
+				irq_setup_affinity(desc);
 			ret = __irq_startup(desc);
-			irq_setup_affinity(desc);
+			if (!(d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP))
+				irq_setup_affinity(desc);
 			break;
 		case IRQ_STARTUP_MANAGED:
 			irq_do_set_affinity(d, aff, false);