linux-kernel - [PATCH 5/8] perf/x86: Add is_visible attribute

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Date:   Sat,  4 May 2019 14:52:04 +0200
From:   Jiri Olsa <jolsa@...nel.org>
To:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 5/8] perf/x86: Add is_visible attribute_group callback for base events

We dont need to pre-filter out unsupported base events,
we can just use its group's is_visible function to do this.

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 arch/x86/events/core.c | 52 ++++++++++++------------------------------
 1 file changed, 14 insertions(+), 38 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index a43d8d1e8590..1889e45e6742 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1618,42 +1618,6 @@ static struct attribute_group x86_pmu_format_group __ro_after_init = {
 	.attrs = NULL,
 };
 
-/*
- * Remove all undefined events (x86_pmu.event_map(id) == 0)
- * out of events_attr attributes.
- */
-static void __init filter_events(struct attribute **attrs)
-{
-	struct device_attribute *d;
-	struct perf_pmu_events_attr *pmu_attr;
-	int offset = 0;
-	int i, j;
-
-	for (i = 0; attrs[i]; i++) {
-		d = (struct device_attribute *)attrs[i];
-		pmu_attr = container_of(d, struct perf_pmu_events_attr, attr);
-		/* str trumps id */
-		if (pmu_attr->event_str)
-			continue;
-		if (x86_pmu.event_map(i + offset))
-			continue;
-
-		for (j = i; attrs[j]; j++)
-			attrs[j] = attrs[j + 1];
-
-		/* Check the shifted attr. */
-		i--;
-
-		/*
-		 * event_map() is index based, the attrs array is organized
-		 * by increasing event index. If we shift the events, then
-		 * we need to compensate for the event_map(), otherwise
-		 * we are looking up the wrong event in the map
-		 */
-		offset++;
-	}
-}
-
 /* Merge two pointer arrays */
 __init struct attribute **merge_attr(struct attribute **a, struct attribute **b)
 {
@@ -1744,9 +1708,23 @@ static struct attribute *events_attr[] = {
 	NULL,
 };
 
+/*
+ * Remove all undefined events (x86_pmu.event_map(id) == 0)
+ * out of events_attr attributes.
+ */
+static umode_t
+is_visible(struct kobject *kobj, struct attribute *attr, int idx)
+{
+	struct perf_pmu_events_attr *pmu_attr;
+
+	pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr.attr);
+	return pmu_attr->event_str || x86_pmu.event_map(idx) ? attr->mode : 0;
+}
+
 static struct attribute_group x86_pmu_events_group __ro_after_init = {
 	.name = "events",
 	.attrs = events_attr,
+	.is_visible = is_visible,
 };
 
 ssize_t x86_event_sysfs_show(char *page, u64 config, u64 event)
@@ -1852,8 +1830,6 @@ static int __init init_hw_perf_events(void)
 
 	if (!x86_pmu.events_sysfs_show)
 		x86_pmu_events_group.attrs = &empty_attrs;
-	else
-		filter_events(x86_pmu_events_group.attrs);
 
 	if (x86_pmu.attrs) {
 		struct attribute **tmp;
-- 
2.20.1