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Message-ID: <20231221161106.846599574@goodmis.org>
Date: Thu, 21 Dec 2023 11:10:40 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Tzvetomir Stoyanov <tz.stoyanov@...il.com>,
Vincent Donnefort <vdonnefort@...gle.com>,
Kent Overstreet <kent.overstreet@...il.com>
Subject: [for-next][PATCH 16/16] ring-buffer: Use subbuf_order for buffer page masking
From: "Steven Rostedt (Google)" <rostedt@...dmis.org>
The comparisons to PAGE_SIZE were all converted to use the
buffer->subbuf_order, but the use of PAGE_MASK was missed.
Convert all the PAGE_MASK usages over to:
(PAGE_SIZE << cpu_buffer->buffer->subbuf_order) - 1
Link: https://lore.kernel.org/linux-trace-kernel/20231219173800.66eefb7a@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@...il.com>
Cc: Vincent Donnefort <vdonnefort@...gle.com>
Cc: Kent Overstreet <kent.overstreet@...il.com>
Fixes: 139f84002145 ("ring-buffer: Page size per ring buffer")
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
kernel/trace/ring_buffer.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 7ee6779bf292..173d2595ce2d 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2269,11 +2269,13 @@ rb_commit_index(struct ring_buffer_per_cpu *cpu_buffer)
}
static __always_inline unsigned
-rb_event_index(struct ring_buffer_event *event)
+rb_event_index(struct ring_buffer_per_cpu *cpu_buffer, struct ring_buffer_event *event)
{
unsigned long addr = (unsigned long)event;
- return (addr & ~PAGE_MASK) - BUF_PAGE_HDR_SIZE;
+ addr &= (PAGE_SIZE << cpu_buffer->buffer->subbuf_order) - 1;
+
+ return addr - BUF_PAGE_HDR_SIZE;
}
static void rb_inc_iter(struct ring_buffer_iter *iter)
@@ -2646,7 +2648,8 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
/* Slow path */
static struct ring_buffer_event *
-rb_add_time_stamp(struct ring_buffer_event *event, u64 delta, bool abs)
+rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
+ struct ring_buffer_event *event, u64 delta, bool abs)
{
if (abs)
event->type_len = RINGBUF_TYPE_TIME_STAMP;
@@ -2654,7 +2657,7 @@ rb_add_time_stamp(struct ring_buffer_event *event, u64 delta, bool abs)
event->type_len = RINGBUF_TYPE_TIME_EXTEND;
/* Not the first event on the page, or not delta? */
- if (abs || rb_event_index(event)) {
+ if (abs || rb_event_index(cpu_buffer, event)) {
event->time_delta = delta & TS_MASK;
event->array[0] = delta >> TS_SHIFT;
} else {
@@ -2728,7 +2731,7 @@ static void rb_add_timestamp(struct ring_buffer_per_cpu *cpu_buffer,
if (!abs)
info->delta = 0;
}
- *event = rb_add_time_stamp(*event, info->delta, abs);
+ *event = rb_add_time_stamp(cpu_buffer, *event, info->delta, abs);
*length -= RB_LEN_TIME_EXTEND;
*delta = 0;
}
@@ -2812,10 +2815,10 @@ rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
struct buffer_page *bpage;
unsigned long addr;
- new_index = rb_event_index(event);
+ new_index = rb_event_index(cpu_buffer, event);
old_index = new_index + rb_event_ts_length(event);
addr = (unsigned long)event;
- addr &= PAGE_MASK;
+ addr &= ~((PAGE_SIZE << cpu_buffer->buffer->subbuf_order) - 1);
bpage = READ_ONCE(cpu_buffer->tail_page);
@@ -3726,7 +3729,7 @@ rb_decrement_entry(struct ring_buffer_per_cpu *cpu_buffer,
struct buffer_page *bpage = cpu_buffer->commit_page;
struct buffer_page *start;
- addr &= PAGE_MASK;
+ addr &= ~((PAGE_SIZE << cpu_buffer->buffer->subbuf_order) - 1);
/* Do the likely case first */
if (likely(bpage->page == (void *)addr)) {
--
2.42.0
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