Commit 8f2221f5 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf/core: Simplify perf_event_alloc() 



Using the previous simplifications, transition perf_event_alloc() to
the cleanup way of things -- reducing error path magic.

[ mingo: Ported it to recent kernels. ]

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarRavi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20241104135518.410755241@infradead.org
parent caf8b765

kernel/events/core.c

+22 −37
Original line number Diff line number Diff line
@@ -5410,6 +5410,8 @@ static void __free_event(struct perf_event *event) 
	call_rcu(&event->rcu_head, free_event_rcu);

}



DEFINE_FREE(__free_event, struct perf_event *, if (_T) __free_event(_T))



/* vs perf_event_alloc() success */

static void _free_event(struct perf_event *event)

{
@@ -12291,7 +12293,6 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, 
		 void *context, int cgroup_fd)

{

	struct pmu *pmu;

	struct perf_event *event;

	struct hw_perf_event *hwc;

	long err = -EINVAL;

	int node;
@@ -12306,8 +12307,8 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, 
	}



	node = (cpu >= 0) ? cpu_to_node(cpu) : -1;

	event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,

				      node);

	struct perf_event *event __free(__free_event) =

		kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, node);

	if (!event)

		return ERR_PTR(-ENOMEM);
@@ -12414,65 +12415,53 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, 
	 * See perf_output_read().

	 */

	if (has_inherit_and_sample_read(attr) && !(attr->sample_type & PERF_SAMPLE_TID))

		goto err;

		return ERR_PTR(-EINVAL);



	if (!has_branch_stack(event))

		event->attr.branch_sample_type = 0;



	pmu = perf_init_event(event);

	if (IS_ERR(pmu)) {

		err = PTR_ERR(pmu);

		goto err;

	}

	if (IS_ERR(pmu))

		return (void*)pmu;



	/*

	 * Disallow uncore-task events. Similarly, disallow uncore-cgroup

	 * events (they don't make sense as the cgroup will be different

	 * on other CPUs in the uncore mask).

	 */

	if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) {

		err = -EINVAL;

		goto err;

	}

	if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1))

		return ERR_PTR(-EINVAL);



	if (event->attr.aux_output &&

	    (!(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT) ||

	     event->attr.aux_pause || event->attr.aux_resume)) {

		err = -EOPNOTSUPP;

		goto err;

	}

	     event->attr.aux_pause || event->attr.aux_resume))

		return ERR_PTR(-EOPNOTSUPP);



	if (event->attr.aux_pause && event->attr.aux_resume) {

		err = -EINVAL;

		goto err;

	}

	if (event->attr.aux_pause && event->attr.aux_resume)

		return ERR_PTR(-EINVAL);



	if (event->attr.aux_start_paused) {

		if (!(pmu->capabilities & PERF_PMU_CAP_AUX_PAUSE)) {

			err = -EOPNOTSUPP;

			goto err;

		}

		if (!(pmu->capabilities & PERF_PMU_CAP_AUX_PAUSE))

			return ERR_PTR(-EOPNOTSUPP);

		event->hw.aux_paused = 1;

	}



	if (cgroup_fd != -1) {

		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);

		if (err)

			goto err;

			return ERR_PTR(err);

	}



	err = exclusive_event_init(event);

	if (err)

		goto err;

		return ERR_PTR(err);



	if (has_addr_filter(event)) {

		event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,

						    sizeof(struct perf_addr_filter_range),

						    GFP_KERNEL);

		if (!event->addr_filter_ranges) {

			err = -ENOMEM;

			goto err;

		}

		if (!event->addr_filter_ranges)

			return ERR_PTR(-ENOMEM);



		/*

		 * Clone the parent's vma offsets: they are valid until exec()
@@ -12496,23 +12485,19 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, 
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {

			err = get_callchain_buffers(attr->sample_max_stack);

			if (err)

				goto err;

				return ERR_PTR(err);

			event->attach_state |= PERF_ATTACH_CALLCHAIN;

		}

	}



	err = security_perf_event_alloc(event);

	if (err)

		goto err;

		return ERR_PTR(err);



	/* symmetric to unaccount_event() in _free_event() */

	account_event(event);



	return event;



err:

	__free_event(event);

	return ERR_PTR(err);

	return_ptr(event);

}



static int perf_copy_attr(struct perf_event_attr __user *uattr,