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71f0a24786
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 <tglx@linutronix.de> Signed-off-by: Eli Cohen <elic@nvidia.com> Signed-off-by: Saeed Mahameed <saeedm@nvidia.com> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __LINUX_CPU_RMAP_H
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#define __LINUX_CPU_RMAP_H
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/*
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* cpu_rmap.c: CPU affinity reverse-map support
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* Copyright 2011 Solarflare Communications Inc.
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*/
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#include <linux/cpumask.h>
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#include <linux/gfp.h>
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#include <linux/slab.h>
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#include <linux/kref.h>
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/**
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* struct cpu_rmap - CPU affinity reverse-map
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* @refcount: kref for object
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* @size: Number of objects to be reverse-mapped
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* @obj: Pointer to array of object pointers
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* @near: For each CPU, the index and distance to the nearest object,
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* based on affinity masks
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*/
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struct cpu_rmap {
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struct kref refcount;
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u16 size;
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void **obj;
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struct {
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u16 index;
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u16 dist;
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} near[];
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};
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#define CPU_RMAP_DIST_INF 0xffff
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extern struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags);
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extern int cpu_rmap_put(struct cpu_rmap *rmap);
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extern int cpu_rmap_add(struct cpu_rmap *rmap, void *obj);
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extern int cpu_rmap_update(struct cpu_rmap *rmap, u16 index,
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const struct cpumask *affinity);
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static inline u16 cpu_rmap_lookup_index(struct cpu_rmap *rmap, unsigned int cpu)
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{
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return rmap->near[cpu].index;
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}
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static inline void *cpu_rmap_lookup_obj(struct cpu_rmap *rmap, unsigned int cpu)
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{
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return rmap->obj[rmap->near[cpu].index];
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}
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/**
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* alloc_irq_cpu_rmap - allocate CPU affinity reverse-map for IRQs
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* @size: Number of objects to be mapped
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*
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* Must be called in process context.
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*/
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static inline struct cpu_rmap *alloc_irq_cpu_rmap(unsigned int size)
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{
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return alloc_cpu_rmap(size, GFP_KERNEL);
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}
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extern void free_irq_cpu_rmap(struct cpu_rmap *rmap);
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int irq_cpu_rmap_remove(struct cpu_rmap *rmap, int irq);
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extern int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq);
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#endif /* __LINUX_CPU_RMAP_H */
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