perf: Use sample_flags for raw_data

Use the new sample_flags to indicate whether the raw data field is
filled by the PMU driver.  Although it could check with the NULL,
follow the same rule with other fields.

Remove the raw field from the perf_sample_data_init() to minimize
the number of cache lines touched.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220921220032.2858517-2-namhyung@kernel.org

arch/s390/kernel/perf_cpum_cf.c

@@ -664,6 +664,7 @@ static int cfdiag_push_sample(struct perf_event *event,
 		raw.frag.data = cpuhw->stop;
 		raw.size = raw.frag.size;
 		data.raw = &raw;
+		data.sample_flags |= PERF_SAMPLE_RAW;
 	}
 
 	overflow = perf_event_overflow(event, &data, &regs);

arch/s390/kernel/perf_pai_crypto.c

@@ -366,6 +366,7 @@ static int paicrypt_push_sample(void)
 		raw.frag.data = cpump->save;
 		raw.size = raw.frag.size;
 		data.raw = &raw;
+		data.sample_flags |= PERF_SAMPLE_RAW;
 	}
 
 	overflow = perf_event_overflow(event, &data, &regs);

arch/x86/events/amd/ibs.c

@@ -781,6 +781,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 			},
 		};
 		data.raw = &raw;
+		data.sample_flags |= PERF_SAMPLE_RAW;
 	}
 
 	/*

include/linux/perf_event.h

@@ -1028,7 +1028,6 @@ struct perf_sample_data {
 	 * minimize the cachelines touched.
 	 */
 	u64				sample_flags;
-	struct perf_raw_record		*raw;
 	u64				period;
 
 	/*
@@ -1040,6 +1039,7 @@ struct perf_sample_data {
 	union  perf_mem_data_src	data_src;
 	u64				txn;
 	u64				addr;
+	struct perf_raw_record		*raw;
 
 	u64				type;
 	u64				ip;
@@ -1078,8 +1078,7 @@ static inline void perf_sample_data_init(struct perf_sample_data *data,
 					 u64 addr, u64 period)
 {
 	/* remaining struct members initialized in perf_prepare_sample() */
-	data->sample_flags = 0;
-	data->raw  = NULL;
+	data->sample_flags = PERF_SAMPLE_PERIOD;
 	data->period = period;
 
 	if (addr) {

kernel/events/core.c

@@ -7332,7 +7332,7 @@ void perf_prepare_sample(struct perf_event_header *header,
 		struct perf_raw_record *raw = data->raw;
 		int size;
 
-		if (raw) {
+		if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) {
 			struct perf_raw_frag *frag = &raw->frag;
 			u32 sum = 0;
 
@@ -7348,6 +7348,7 @@ void perf_prepare_sample(struct perf_event_header *header,
 			frag->pad = raw->size - sum;
 		} else {
 			size = sizeof(u64);
+			data->raw = NULL;
 		}
 
 		header->size += size;