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>
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 35df94e..34a1b9d7 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -4780,14 +4780,17 @@
*/
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);
- err = PTR_ERR(event);
- if (IS_ERR(event))
+ if (IS_ERR(event)) {
+ err = PTR_ERR(event);
goto err_put_context;
+ }
event->filp = NULL;
WARN_ON_ONCE(ctx->parent_ctx);
@@ -4804,11 +4807,10 @@
return event;
-err_put_context:
- if (err < 0)
- put_ctx(ctx);
-
- return NULL;
+ err_put_context:
+ put_ctx(ctx);
+ err_exit:
+ return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);