[tip: timers/core] tracing: Use explicit array size instead of sentinel elements in symbol printing

[tip-bot2 for Thomas Weißschuh (Schneider Electric)]

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

Commit-ID:     754e38d2d1aeeadddac5220f34e07cf263502a46
Gitweb:        https://git.kernel.org/tip/754e38d2d1aeeadddac5220f34e07cf263502a46
Author:        Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@xxxxxxxxxxxxx>
AuthorDate:    Wed, 11 Mar 2026 11:15:11 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxx>
CommitterDate: Thu, 12 Mar 2026 12:15:53 +01:00

tracing: Use explicit array size instead of sentinel elements in symbol printing

The sentinel value added by the wrapper macros __print_symbolic() et al
prevents the callers from adding their own trailing comma. This makes
constructing symbol list dynamically based on kconfig values tedious.

Drop the sentinel elements, so callers can either specify the trailing
comma or not, just like in regular array initializers.

Signed-off-by: Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxx>
Link: https://patch.msgid.link/20260311-hrtimer-cleanups-v1-2-095357392669@xxxxxxxxxxxxx
---
 include/linux/trace_events.h               | 13 ++++---
 include/trace/stages/stage3_trace_output.h | 40 ++++++++++-----------
 kernel/trace/trace_events_synth.c          |  4 +-
 kernel/trace/trace_output.c                | 20 ++++++-----
 kernel/trace/trace_syscalls.c              |  3 +--
 5 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 37eb2f0..40a43a4 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -22,20 +22,23 @@ union bpf_attr;
 
 const char *trace_print_flags_seq(struct trace_seq *p, const char *delim,
 				  unsigned long flags,
-				  const struct trace_print_flags *flag_array);
+				  const struct trace_print_flags *flag_array,
+				  size_t flag_array_size);
 
 const char *trace_print_symbols_seq(struct trace_seq *p, unsigned long val,
-				    const struct trace_print_flags *symbol_array);
+				    const struct trace_print_flags *symbol_array,
+				    size_t symbol_array_size);
 
 #if BITS_PER_LONG == 32
 const char *trace_print_flags_seq_u64(struct trace_seq *p, const char *delim,
 		      unsigned long long flags,
-		      const struct trace_print_flags_u64 *flag_array);
+		      const struct trace_print_flags_u64 *flag_array,
+		      size_t flag_array_size);
 
 const char *trace_print_symbols_seq_u64(struct trace_seq *p,
 					unsigned long long val,
-					const struct trace_print_flags_u64
-								 *symbol_array);
+					const struct trace_print_flags_u64 *symbol_array,
+					size_t symbol_array_size);
 #endif
 
 struct trace_iterator;
diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h
index fce85ea..b7d8ef4 100644
--- a/include/trace/stages/stage3_trace_output.h
+++ b/include/trace/stages/stage3_trace_output.h
@@ -64,36 +64,36 @@
 #define __get_rel_sockaddr(field)	((struct sockaddr *)__get_rel_dynamic_array(field))
 
 #undef __print_flags
-#define __print_flags(flag, delim, flag_array...)			\
-	({								\
-		static const struct trace_print_flags __flags[] =	\
-			{ flag_array, { -1, NULL }};			\
-		trace_print_flags_seq(p, delim, flag, __flags);	\
+#define __print_flags(flag, delim, flag_array...)					\
+	({										\
+		static const struct trace_print_flags __flags[] =			\
+			{ flag_array };							\
+		trace_print_flags_seq(p, delim, flag, __flags, ARRAY_SIZE(__flags));	\
 	})
 
 #undef __print_symbolic
-#define __print_symbolic(value, symbol_array...)			\
-	({								\
-		static const struct trace_print_flags symbols[] =	\
-			{ symbol_array, { -1, NULL }};			\
-		trace_print_symbols_seq(p, value, symbols);		\
+#define __print_symbolic(value, symbol_array...)					\
+	({										\
+		static const struct trace_print_flags symbols[] =			\
+			{ symbol_array };						\
+		trace_print_symbols_seq(p, value, symbols, ARRAY_SIZE(symbols));	\
 	})
 
 #undef __print_flags_u64
 #undef __print_symbolic_u64
 #if BITS_PER_LONG == 32
-#define __print_flags_u64(flag, delim, flag_array...)			\
-	({								\
-		static const struct trace_print_flags_u64 __flags[] =	\
-			{ flag_array, { -1, NULL } };			\
-		trace_print_flags_seq_u64(p, delim, flag, __flags);	\
+#define __print_flags_u64(flag, delim, flag_array...)						\
+	({											\
+		static const struct trace_print_flags_u64 __flags[] =				\
+			{ flag_array };								\
+		trace_print_flags_seq_u64(p, delim, flag, __flags, ARRAY_SIZE(__flags));	\
 	})
 
-#define __print_symbolic_u64(value, symbol_array...)			\
-	({								\
-		static const struct trace_print_flags_u64 symbols[] =	\
-			{ symbol_array, { -1, NULL } };			\
-		trace_print_symbols_seq_u64(p, value, symbols);	\
+#define __print_symbolic_u64(value, symbol_array...)					\
+	({										\
+		static const struct trace_print_flags_u64 symbols[] =			\
+			{ symbol_array };						\
+		trace_print_symbols_seq_u64(p, value, symbols, ARRAY_SIZE(symbols));	\
 	})
 #else
 #define __print_flags_u64(flag, delim, flag_array...)			\
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 8bb95b2..39ac4eb 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -395,7 +395,7 @@ static enum print_line_t print_synth_event(struct trace_iterator *iter,
 			n_u64++;
 		} else {
 			struct trace_print_flags __flags[] = {
-			    __def_gfpflag_names, {-1, NULL} };
+			    __def_gfpflag_names };
 			char *space = (i == se->n_fields - 1 ? "" : " ");
 
 			print_synth_event_num_val(s, print_fmt,
@@ -408,7 +408,7 @@ static enum print_line_t print_synth_event(struct trace_iterator *iter,
 				trace_seq_puts(s, " (");
 				trace_print_flags_seq(s, "|",
 						      entry->fields[n_u64].as_u64,
-						      __flags);
+						      __flags, ARRAY_SIZE(__flags));
 				trace_seq_putc(s, ')');
 			}
 			n_u64++;
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 1996d7a..96e2d22 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -69,14 +69,15 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
 const char *
 trace_print_flags_seq(struct trace_seq *p, const char *delim,
 		      unsigned long flags,
-		      const struct trace_print_flags *flag_array)
+		      const struct trace_print_flags *flag_array,
+		      size_t flag_array_size)
 {
 	unsigned long mask;
 	const char *str;
 	const char *ret = trace_seq_buffer_ptr(p);
 	int i, first = 1;
 
-	for (i = 0;  flag_array[i].name && flags; i++) {
+	for (i = 0; i < flag_array_size && flags; i++) {
 
 		mask = flag_array[i].mask;
 		if ((flags & mask) != mask)
@@ -106,12 +107,13 @@ EXPORT_SYMBOL(trace_print_flags_seq);
 
 const char *
 trace_print_symbols_seq(struct trace_seq *p, unsigned long val,
-			const struct trace_print_flags *symbol_array)
+			const struct trace_print_flags *symbol_array,
+			size_t symbol_array_size)
 {
 	int i;
 	const char *ret = trace_seq_buffer_ptr(p);
 
-	for (i = 0;  symbol_array[i].name; i++) {
+	for (i = 0; i < symbol_array_size; i++) {
 
 		if (val != symbol_array[i].mask)
 			continue;
@@ -133,14 +135,15 @@ EXPORT_SYMBOL(trace_print_symbols_seq);
 const char *
 trace_print_flags_seq_u64(struct trace_seq *p, const char *delim,
 		      unsigned long long flags,
-		      const struct trace_print_flags_u64 *flag_array)
+		      const struct trace_print_flags_u64 *flag_array,
+		      size_t flag_array_size)
 {
 	unsigned long long mask;
 	const char *str;
 	const char *ret = trace_seq_buffer_ptr(p);
 	int i, first = 1;
 
-	for (i = 0;  flag_array[i].name && flags; i++) {
+	for (i = 0; i < flag_array_size && flags; i++) {
 
 		mask = flag_array[i].mask;
 		if ((flags & mask) != mask)
@@ -170,12 +173,13 @@ EXPORT_SYMBOL(trace_print_flags_seq_u64);
 
 const char *
 trace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val,
-			 const struct trace_print_flags_u64 *symbol_array)
+			    const struct trace_print_flags_u64 *symbol_array,
+			    size_t symbol_array_size)
 {
 	int i;
 	const char *ret = trace_seq_buffer_ptr(p);
 
-	for (i = 0;  symbol_array[i].name; i++) {
+	for (i = 0; i < symbol_array_size; i++) {
 
 		if (val != symbol_array[i].mask)
 			continue;
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 37317b8..8ad72e1 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -174,7 +174,6 @@ sys_enter_openat_print(struct syscall_trace_enter *trace, struct syscall_metadat
 			{ O_NOFOLLOW, "O_NOFOLLOW" },
 			{ O_NOATIME, "O_NOATIME" },
 			{ O_CLOEXEC, "O_CLOEXEC" },
-			{ -1, NULL }
 		};
 
 	trace_seq_printf(s, "%s(", entry->name);
@@ -205,7 +204,7 @@ sys_enter_openat_print(struct syscall_trace_enter *trace, struct syscall_metadat
 				trace_seq_puts(s, "O_RDONLY|");
 			}
 
-			trace_print_flags_seq(s, "|", bits, __flags);
+			trace_print_flags_seq(s, "|", bits, __flags, ARRAY_SIZE(__flags));
 			/*
 			 * trace_print_flags_seq() adds a '\0' to the
 			 * buffer, but this needs to append more to the seq.