linux-kernel - [PATCH v5 2/5] perf/x86/lbr: Simplify the exposure check for the LBR

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Date:   Fri, 26 Mar 2021 09:19:15 +0800
From:   Like Xu <like.xu@...ux.intel.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Namhyung Kim <namhyung@...nel.org>
Cc:     pbonzini@...hat.com, Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Kan Liang <kan.liang@...ux.intel.com>, wei.w.wang@...el.com,
        x86@...nel.org, linux-kernel@...r.kernel.org,
        Like Xu <like.xu@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH v5 2/5] perf/x86/lbr: Simplify the exposure check for the LBR_INFO registers

The x86_pmu.lbr_info is 0 unless explicitly initialized, so there's
no point checking x86_pmu.intel_cap.lbr_format.

Signed-off-by: Like Xu <like.xu@...ux.intel.com>
Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
---
 arch/x86/events/intel/lbr.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 21890dacfcfe..355ea70f1879 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -1832,12 +1832,10 @@ void __init intel_pmu_arch_lbr_init(void)
  */
 int x86_perf_get_lbr(struct x86_pmu_lbr *lbr)
 {
-	int lbr_fmt = x86_pmu.intel_cap.lbr_format;
-
 	lbr->nr = x86_pmu.lbr_nr;
 	lbr->from = x86_pmu.lbr_from;
 	lbr->to = x86_pmu.lbr_to;
-	lbr->info = (lbr_fmt == LBR_FORMAT_INFO) ? x86_pmu.lbr_info : 0;
+	lbr->info = x86_pmu.lbr_info;
 
 	return 0;
 }
-- 
2.29.2