[PATCH] ring-buffer: Use a macro for static buffer bits
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2026-09-04 19:15:39
Also in:
lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
From: Steven Rostedt <rostedt@goodmis.org> Instead of hard coding 30 for the number of bits used for the static buffer ids in two places, create a macro. This way if it changes in the future, it will change in all the locations that use it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/trace/ring_buffer.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 220b8405adfc..b88c75b52e8f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c@@ -335,6 +335,9 @@ static __always_inline unsigned int rb_read_page_capacity(struct buffer_data_rea return (PAGE_SIZE << rpage->order) - BUF_PAGE_HDR_SIZE; } +/* The number of bits for static buffer ids */ +#define RB_STATIC_BITS 30 + /* * Note, the buffer_page list must be first. The buffer pages * are allocated in cache lines, which means that each buffer
@@ -350,7 +353,7 @@ struct buffer_page { local_t entries; /* entries on this page */ unsigned long real_end; /* real end of data */ unsigned order; /* order of the page */ - u32 id:30; /* ID for external mapping */ + u32 id:RB_STATIC_BITS; /* ID for external mapping */ u32 range:1; /* Mapped via a range */ struct buffer_data_page *page; /* Actual data page */ };
@@ -663,7 +666,7 @@ static unsigned long rb_static_max_pages(void) * Static ring buffers are using bpage::id and must account for the * reader page. */ - return (1UL << 30) - 1; + return (1UL << RB_STATIC_BITS) - 1; } struct ring_buffer_iter {
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2.53.0