blktrace: report EBUSY correctly

blk_trace_remove_queue() returns EINVAL if q->blk_trace == NULL,
but blk_trace_setup_queue() doesn't return EBUSY if
q->blk_trace != NULL.

 # echo 0 > sdaX/trace/enable
 # echo 0 > sdaX/trace/enable
 bash: echo: write error: Invalid argument
 # echo 1 > sdaX/trace/enable
 # echo 1 > sdaX/trace/enable
 (should return EBUSY)

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49C2F614.2010101@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Li Zefan 2009-03-20 09:49:08 +08:00 committed by Ingo Molnar
parent cbe28296eb
commit 15152e448b

View file

@ -1260,12 +1260,10 @@ static int blk_trace_remove_queue(struct request_queue *q)
static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
{
struct blk_trace *old_bt, *bt = NULL;
int ret;
ret = -ENOMEM;
bt = kzalloc(sizeof(*bt), GFP_KERNEL);
if (!bt)
goto err;
return -ENOMEM;
bt->dev = dev;
bt->act_mask = (u16)-1;
@ -1276,11 +1274,10 @@ static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
if (old_bt != NULL) {
(void)xchg(&q->blk_trace, old_bt);
kfree(bt);
ret = -EBUSY;
return -EBUSY;
}
return 0;
err:
return ret;
}
/*