66341a905e
Currently per_cpu_ptr() doesn't really do anything with 'cpu' in the UP case. This is problematic in the cases where this is the only place the variable is referenced: CC kernel/workqueue.o kernel/workqueue.c: In function `current_is_keventd': kernel/workqueue.c:460: warning: unused variable `cpu' Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
#ifndef __LINUX_PERCPU_H
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#define __LINUX_PERCPU_H
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#include <linux/spinlock.h> /* For preempt_disable() */
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#include <linux/slab.h> /* For kmalloc() */
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#include <linux/smp.h>
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#include <linux/string.h> /* For memset() */
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#include <asm/percpu.h>
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/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
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#ifndef PERCPU_ENOUGH_ROOM
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#define PERCPU_ENOUGH_ROOM 32768
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#endif
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/* Must be an lvalue. */
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#define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); }))
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#define put_cpu_var(var) preempt_enable()
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#ifdef CONFIG_SMP
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struct percpu_data {
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void *ptrs[NR_CPUS];
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void *blkp;
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};
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/*
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* Use this to get to a cpu's version of the per-cpu object allocated using
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* alloc_percpu. Non-atomic access to the current CPU's version should
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* probably be combined with get_cpu()/put_cpu().
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*/
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#define per_cpu_ptr(ptr, cpu) \
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({ \
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struct percpu_data *__p = (struct percpu_data *)~(unsigned long)(ptr); \
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(__typeof__(ptr))__p->ptrs[(cpu)]; \
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})
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extern void *__alloc_percpu(size_t size, size_t align);
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extern void free_percpu(const void *);
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#else /* CONFIG_SMP */
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#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
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static inline void *__alloc_percpu(size_t size, size_t align)
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{
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void *ret = kmalloc(size, GFP_KERNEL);
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if (ret)
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memset(ret, 0, size);
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return ret;
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}
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static inline void free_percpu(const void *ptr)
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{
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kfree(ptr);
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}
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#endif /* CONFIG_SMP */
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/* Simple wrapper for the common case: zeros memory. */
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#define alloc_percpu(type) \
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((type *)(__alloc_percpu(sizeof(type), __alignof__(type))))
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#endif /* __LINUX_PERCPU_H */
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