From 32e0f607ac6a2bb5d144540897535fd01be77586 Mon Sep 17 00:00:00 2001
From: Steven Rostedt <rostedt@goodmis.org>
Date: Tue, 28 Oct 2025 19:11:24 -0400
Subject: tracing: Add trace_seq_pop() and seq_buf_pop()

In order to allow an interface to remove an added character from the
trace_seq and seq_buf descriptors, add helper functions trace_seq_pop()
and seq_buf_pop().

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Takaya Saeki <takayas@google.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/20251028231148.594898736@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/linux/trace_seq.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'include/linux/trace_seq.h')

diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 557780fe1c77..4a0b8c172d27 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -80,6 +80,19 @@ static inline bool trace_seq_has_overflowed(struct trace_seq *s)
 	return s->full || seq_buf_has_overflowed(&s->seq);
 }
 
+/**
+ * trace_seq_pop - pop off the last written character
+ * @s: trace sequence descriptor
+ *
+ * Removes the last written character to the trace_seq @s.
+ *
+ * Returns the last character or -1 if it is empty.
+ */
+static inline int trace_seq_pop(struct trace_seq *s)
+{
+	return seq_buf_pop(&s->seq);
+}
+
 /*
  * Currently only defined when tracing is enabled.
  */
-- 
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