Commit c6567f64 authored Nov 26, 2009 by Frederic Weisbecker Committed by Ingo Molnar Nov 26, 2009

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: Frederic 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: Ingo Molnar <mingo@elte.hu>

parent d99be40a

kernel/perf_event.c

+11 −9

Original line number	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);
		if (IS_ERR(ctx))
		return NULL;
		if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
		goto err_exit;
		}

		event = perf_event_alloc(attr, cpu, ctx, NULL,
		NULL, callback, GFP_KERNEL);
		if (IS_ERR(event)) {
		err = PTR_ERR(event);
		if (IS_ERR(event))
		goto err_put_context;
		}

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

		err_put_context:
		if (err < 0)
		put_ctx(ctx);

		return NULL;
		err_exit:
		return ERR_PTR(err);
		}
		EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);

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