[tip: perf/core] perf/x86: Fix fall-through warnings for Clang

[tip-bot2 for Gustavo A. R. Silva]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     b6459575451769b0550621865d1ddb65afdb55a1
Gitweb:        https://git.kernel.org/tip/b6459575451769b0550621865d1ddb65afdb55a1
Author:        Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
AuthorDate:    Fri, 20 Nov 2020 12:31:36 -06:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 09 Dec 2020 17:08:59 +01:00

perf/x86: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a fallthrough pseudo-keyword as a replacement for
a /* fall through */ comment, instead of letting the code fall through
to the next case.

Notice that Clang doesn't recognize /* fall through */ comments as
implicit fall-through markings.

Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://github.com/KSPP/linux/issues/115
---
 arch/x86/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index a88c94d..550c5e7 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1174,7 +1174,7 @@ static inline void x86_assign_hw_event(struct perf_event *event,
 	case INTEL_PMC_IDX_METRIC_BASE ... INTEL_PMC_IDX_METRIC_END:
 		/* All the metric events are mapped onto the fixed counter 3. */
 		idx = INTEL_PMC_IDX_FIXED_SLOTS;
-		/* fall through */
+		fallthrough;
 	case INTEL_PMC_IDX_FIXED ... INTEL_PMC_IDX_FIXED_BTS-1:
 		hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL;
 		hwc->event_base = MSR_ARCH_PERFMON_FIXED_CTR0 +