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percpu_ida: add percpu_ida_for_each_free

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Add a new API to iterate free ids. blk-mq-tag will use it.

Note, this doesn't guarantee to iterate all free ids restrictly. Caller
should be aware of this. blk-mq uses it to do sanity check for request
timedout, so can tolerate the limitation.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Shaohua Li 2013-10-15 09:05:02 +08:00 • committed by Jens Axboe
parent e26b53d0b2
commit 7fc2ba17e8
2 changed files with 48 additions and 0 deletions
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4
include/linux/percpu_ida.h
View file

@ -73,4 +73,8 @@ static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags
IDA_DEFAULT_PCPU_BATCH_MOVE); IDA_DEFAULT_PCPU_BATCH_MOVE);
} }
typedef int (*percpu_ida_cb)(unsigned, void *);
int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
void *data);
#endif /* __PERCPU_IDA_H__ */ #endif /* __PERCPU_IDA_H__ */

44
lib/percpu_ida.c
View file

@ -327,3 +327,47 @@ err:
return -ENOMEM; return -ENOMEM;
} }
EXPORT_SYMBOL_GPL(__percpu_ida_init); EXPORT_SYMBOL_GPL(__percpu_ida_init);
/**
* percpu_ida_for_each_free - iterate free ids of a pool
* @pool: pool to iterate
* @fn: interate callback function
* @data: parameter for @fn
*
* Note, this doesn't guarantee to iterate all free ids restrictly. Some free
* ids might be missed, some might be iterated duplicated, and some might
* be iterated and not free soon.
*/
int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
void *data)
{
unsigned long flags;
struct percpu_ida_cpu *remote;
unsigned cpu, i, err = 0;
local_irq_save(flags);
for_each_possible_cpu(cpu) {
remote = per_cpu_ptr(pool->tag_cpu, cpu);
spin_lock(&remote->lock);
for (i = 0; i < remote->nr_free; i++) {
err = fn(remote->freelist[i], data);
if (err)
break;
}
spin_unlock(&remote->lock);
if (err)
goto out;
}
spin_lock(&pool->lock);
for (i = 0; i < pool->nr_free; i++) {
err = fn(pool->freelist[i], data);
if (err)
break;
}
spin_unlock(&pool->lock);
out:
local_irq_restore(flags);
return err;
}
EXPORT_SYMBOL_GPL(percpu_ida_for_each_free);