Commit 15152e44 authored Mar 20, 2009 by Li Zefan Committed by Ingo Molnar Mar 21, 2009

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>

parent cbe28296

kernel/trace/blktrace.c

+3 −6

Original line number	Diff line number	Diff line
		@@ -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;
		}

		/*

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