Patch "irqdomain: Look for existing mapping only once" has been added to the 5.4-stable tree

gregkh
2023-04-11T14:20:04Z

This is a note to let you know that I've just added the patch titled

irqdomain: Look for existing mapping only once

to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
irqdomain-look-for-existing-mapping-only-once.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.

From stable-owner@vger.kernel.org Wed Mar 22 13:46:06 2023
From: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Date: Wed, 22 Mar 2023 20:45:48 +0800
Subject: irqdomain: Look for existing mapping only once
To: Marc Zyngier <maz@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Matthias Brugger <matthias.bgg@gmail.com>
Cc: Johan Hovold <johan+linaro@kernel.org>, <stable@vger.kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Mark-PK Tsai <mark-pk.tsai@mediatek.com>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-mediatek@lists.infradead.org>
Message-ID: <20230322124550.29812-1-mark-pk.tsai@mediatek.com>

From: Johan Hovold <johan+linaro@kernel.org>

commit 6e6f75c9c98d2d246d90411ff2b6f0cd271f4cba upstream.

Avoid looking for an existing mapping twice when creating a new mapping
using irq_create_fwspec_mapping() by factoring out the actual allocation
which is shared with irq_create_mapping_affinity().

The new helper function will also be used to fix a shared-interrupt
mapping race, hence the Fixes tag.

Fixes: b62b2cf5759b ("irqdomain: Fix handling of type settings for existing mappings")
Cc: stable@vger.kernel.org # 4.8
Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230213104302.17307-5-johan+linaro@kernel.org
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/irq/irqdomain.c | 62 ++++++++++++++++++++++++++-----------------------
1 file changed, 34 insertions(+), 28 deletions(-)

--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -672,6 +672,34 @@ unsigned int irq_create_direct_mapping(s
}
EXPORT_SYMBOL_GPL(irq_create_direct_mapping);

+static unsigned int __irq_create_mapping_affinity(struct irq_domain *domain,
+ irq_hw_number_t hwirq,
+ const struct irq_affinity_desc *affinity)
+{
+ struct device_node *of_node = irq_domain_get_of_node(domain);
+ int virq;
+
+ pr_debug("irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq);
+
+ /* Allocate a virtual interrupt number */
+ virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node),
+ affinity);
+ if (virq <= 0) {
+ pr_debug("-> virq allocation failed\n");
+ return 0;
+ }
+
+ if (irq_domain_associate(domain, virq, hwirq)) {
+ irq_free_desc(virq);
+ return 0;
+ }
+
+ pr_debug("irq %lu on domain %s mapped to virtual irq %u\n",
+ hwirq, of_node_full_name(of_node), virq);
+
+ return virq;
+}
+
/**
* irq_create_mapping_affinity() - Map a hardware interrupt into linux irq space
* @domain: domain owning this hardware interrupt or NULL for default domain
@@ -684,49 +712,27 @@ EXPORT_SYMBOL_GPL(irq_create_direct_mapp
* on the number returned from that call.
*/
unsigned int irq_create_mapping_affinity(struct irq_domain *domain,
- irq_hw_number_t hwirq,
- const struct irq_affinity_desc *affinity)
+ irq_hw_number_t hwirq,
+ const struct irq_affinity_desc *affinity)
{
- struct device_node *of_node;
int virq;

- pr_debug("irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq);
-
- /* Look for default domain if nececssary */
+ /* Look for default domain if necessary */
if (domain == NULL)
domain = irq_default_domain;
if (domain == NULL) {
WARN(1, "%s(, %lx) called with NULL domain\n", __func__, hwirq);
return 0;
}
- pr_debug("-> using domain @%p\n", domain);
-
- of_node = irq_domain_get_of_node(domain);

/* Check if mapping already exists */
virq = irq_find_mapping(domain, hwirq);
if (virq) {
- pr_debug("-> existing mapping on virq %d\n", virq);
+ pr_debug("existing mapping on virq %d\n", virq);
return virq;
}

- /* Allocate a virtual interrupt number */
- virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node),
- affinity);
- if (virq <= 0) {
- pr_debug("-> virq allocation failed\n");
- return 0;
- }
-
- if (irq_domain_associate(domain, virq, hwirq)) {
- irq_free_desc(virq);
- return 0;
- }
-
- pr_debug("irq %lu on domain %s mapped to virtual irq %u\n",
- hwirq, of_node_full_name(of_node), virq);
-
- return virq;
+ return __irq_create_mapping_affinity(domain, hwirq, affinity);
}
EXPORT_SYMBOL_GPL(irq_create_mapping_affinity);

@@ -866,7 +872,7 @@ unsigned int irq_create_fwspec_mapping(s
return 0;
} else {
/* Create mapping */
- virq = irq_create_mapping(domain, hwirq);
+ virq = __irq_create_mapping_affinity(domain, hwirq, NULL);
if (!virq)
return virq;
}

Patches currently in stable-queue which might be from stable-owner@vger.kernel.org are

queue-5.4/irqdomain-fix-mapping-creation-race.patch
queue-5.4/irqdomain-refactor-__irq_domain_alloc_irqs.patch
queue-5.4/irqdomain-look-for-existing-mapping-only-once.patch