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Commit c6567f64 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

hw-breakpoints: Improve in-kernel event creation error granularity 



In fail case, perf_event_create_kernel_counter() returns NULL
instead of an error, which doesn't help us to inform the user
about the origin of the problem from the outer most callers.
Often we can just return -EINVAL, which doesn't help anyone when
it's eventually about a memory allocation failure.

Then, this patch makes perf_event_create_kernel_counter() always
return a detailed error code.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1259210142-5714-2-git-send-regression-fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d99be40a

kernel/perf_event.c

+11 −9
Original line number Original line Diff line number Diff line
@@ -4780,14 +4780,17 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 
	 */

	 */





	ctx = find_get_context(pid, cpu);

	ctx = find_get_context(pid, cpu);

	if (IS_ERR(ctx))

	if (IS_ERR(ctx)) {

		return NULL;

		err = PTR_ERR(ctx);

		goto err_exit;

	}





	event = perf_event_alloc(attr, cpu, ctx, NULL,

	event = perf_event_alloc(attr, cpu, ctx, NULL,

				     NULL, callback, GFP_KERNEL);

				     NULL, callback, GFP_KERNEL);

	if (IS_ERR(event)) {

		err = PTR_ERR(event);

		err = PTR_ERR(event);

	if (IS_ERR(event))

		goto err_put_context;

		goto err_put_context;

	}





	event->filp = NULL;

	event->filp = NULL;

	WARN_ON_ONCE(ctx->parent_ctx);

	WARN_ON_ONCE(ctx->parent_ctx);
@@ -4805,10 +4808,9 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 
	return event;

	return event;





 err_put_context:

 err_put_context:

	if (err < 0)

	put_ctx(ctx);

	put_ctx(ctx);



 err_exit:

	return NULL;

	return ERR_PTR(err);

}

}

EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);

EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);