From 71f0a2478605c100358a9f9e174849fa643bf8a7 Mon Sep 17 00:00:00 2001 From: Eli Cohen Date: Tue, 14 Feb 2023 11:05:46 +0200 Subject: [PATCH] lib: cpu_rmap: Add irq_cpu_rmap_remove to complement irq_cpu_rmap_add Add a function to complement irq_cpu_rmap_add(). It removes the irq from the reverse mapping by setting the notifier to NULL. The function calls irq_set_affinity_notifier() with NULL at the notify argument which then cancel any pending notifier work and decrement reference on the notifier. When ref count reaches zero, the glue pointer is kfree and the rmap entry is set to NULL serving both to avoid second attempt to release it and also making the rmap entry available for subsequent mapping. It should be noted the drivers usually creates the reverse mapping at initialization time and remove it at unload time so we do not expect failures in allocating rmap due to kref holding the glue entry. Cc: Thomas Gleixner Signed-off-by: Eli Cohen Signed-off-by: Saeed Mahameed Reviewed-by: Jacob Keller --- include/linux/cpu_rmap.h | 1 + lib/cpu_rmap.c | 11 +++++++++++ 2 files changed, 12 insertions(+) diff --git a/include/linux/cpu_rmap.h b/include/linux/cpu_rmap.h index 0ec745e6cd36..cae324d10965 100644 --- a/include/linux/cpu_rmap.h +++ b/include/linux/cpu_rmap.h @@ -60,6 +60,7 @@ static inline struct cpu_rmap *alloc_irq_cpu_rmap(unsigned int size) } extern void free_irq_cpu_rmap(struct cpu_rmap *rmap); +int irq_cpu_rmap_remove(struct cpu_rmap *rmap, int irq); extern int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq); #endif /* __LINUX_CPU_RMAP_H */ diff --git a/lib/cpu_rmap.c b/lib/cpu_rmap.c index 5d4bf7a8b926..73c1636b927b 100644 --- a/lib/cpu_rmap.c +++ b/lib/cpu_rmap.c @@ -285,6 +285,17 @@ static void irq_cpu_rmap_release(struct kref *ref) kfree(glue); } +/** + * irq_cpu_rmap_remove - remove an IRQ from a CPU affinity reverse-map + * @rmap: The reverse-map + * @irq: The IRQ number + */ +int irq_cpu_rmap_remove(struct cpu_rmap *rmap, int irq) +{ + return irq_set_affinity_notifier(irq, NULL); +} +EXPORT_SYMBOL(irq_cpu_rmap_remove); + /** * irq_cpu_rmap_add - add an IRQ to a CPU affinity reverse-map * @rmap: The reverse-map -- 2.25.1