linux-kernel - [PATCH] ring-buffer: Returns 0 on success from ring_buffer

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Message-Id: <20201019142242.11560-1-hqjagain@gmail.com>
Date:   Mon, 19 Oct 2020 22:22:42 +0800
From:   Qiujun Huang <hqjagain@...il.com>
To:     rostedt@...dmis.org, mingo@...hat.com, linux-kernel@...r.kernel.org
Cc:     Qiujun Huang <hqjagain@...il.com>
Subject: [PATCH] ring-buffer: Returns 0 on success from ring_buffer_resize()

We don't need to check the new buffer size, and the return value
had confused resize_buffer_duplicate_size().
...
	ret = ring_buffer_resize(trace_buf->buffer,
		per_cpu_ptr(size_buf->data,cpu_id)->entries, cpu_id);
	if (ret == 0)
		per_cpu_ptr(trace_buf->data, cpu_id)->entries =
			per_cpu_ptr(size_buf->data, cpu_id)->entries;
...

Signed-off-by: Qiujun Huang <hqjagain@...il.com>
---
 kernel/trace/ring_buffer.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 93ef0ab6ea20..3b5f8ec3781e 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1952,18 +1952,18 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	unsigned long nr_pages;
-	int cpu, err = 0;
+	int cpu, err;
 
 	/*
 	 * Always succeed at resizing a non-existent buffer:
 	 */
 	if (!buffer)
-		return size;
+		return 0;
 
 	/* Make sure the requested buffer exists */
 	if (cpu_id != RING_BUFFER_ALL_CPUS &&
 	    !cpumask_test_cpu(cpu_id, buffer->cpumask))
-		return size;
+		return 0;
 
 	nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
 
@@ -2119,7 +2119,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 	}
 
 	mutex_unlock(&buffer->mutex);
-	return size;
+	return 0;
 
  out_err:
 	for_each_buffer_cpu(buffer, cpu) {
-- 
2.17.1