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linux-next/include/linux/cpu_rmap.h
David Decotigny 896f97ea95 lib: cpu_rmap: avoid flushing all workqueues
In some cases, free_irq_cpu_rmap() is called while holding a lock (eg
rtnl).  This can lead to deadlocks, because it invokes
flush_scheduled_work() which ends up waiting for whole system workqueue
to flush, but some pending works might try to acquire the lock we are
already holding.

This commit uses reference-counting to replace
irq_run_affinity_notifiers().  It also removes
irq_run_affinity_notifiers() altogether.

[akpm@linux-foundation.org: eliminate free_cpu_rmap, rename cpu_rmap_reclaim() to cpu_rmap_release(), propagate kref_put() retval from cpu_rmap_put()]
Signed-off-by: David Decotigny <decot@googlers.com>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Acked-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-11 14:54:54 -08:00

73 lines
1.9 KiB
C

#ifndef __LINUX_CPU_RMAP_H
#define __LINUX_CPU_RMAP_H
/*
* cpu_rmap.c: CPU affinity reverse-map support
* Copyright 2011 Solarflare Communications Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation, incorporated herein by reference.
*/
#include <linux/cpumask.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/kref.h>
/**
* struct cpu_rmap - CPU affinity reverse-map
* @refcount: kref for object
* @size: Number of objects to be reverse-mapped
* @used: Number of objects added
* @obj: Pointer to array of object pointers
* @near: For each CPU, the index and distance to the nearest object,
* based on affinity masks
*/
struct cpu_rmap {
struct kref refcount;
u16 size, used;
void **obj;
struct {
u16 index;
u16 dist;
} near[0];
};
#define CPU_RMAP_DIST_INF 0xffff
extern struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags);
extern int cpu_rmap_put(struct cpu_rmap *rmap);
extern int cpu_rmap_add(struct cpu_rmap *rmap, void *obj);
extern int cpu_rmap_update(struct cpu_rmap *rmap, u16 index,
const struct cpumask *affinity);
static inline u16 cpu_rmap_lookup_index(struct cpu_rmap *rmap, unsigned int cpu)
{
return rmap->near[cpu].index;
}
static inline void *cpu_rmap_lookup_obj(struct cpu_rmap *rmap, unsigned int cpu)
{
return rmap->obj[rmap->near[cpu].index];
}
#ifdef CONFIG_GENERIC_HARDIRQS
/**
* alloc_irq_cpu_rmap - allocate CPU affinity reverse-map for IRQs
* @size: Number of objects to be mapped
*
* Must be called in process context.
*/
static inline struct cpu_rmap *alloc_irq_cpu_rmap(unsigned int size)
{
return alloc_cpu_rmap(size, GFP_KERNEL);
}
extern void free_irq_cpu_rmap(struct cpu_rmap *rmap);
extern int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq);
#endif
#endif /* __LINUX_CPU_RMAP_H */