[PATCH 4.14 105/125] ring-buffer: Return 0 on success from ring_buffer_resize()

Greg Kroah-Hartman
2020-11-03T21:14:08Z

From: Qiujun Huang <hqjagain@gmail.com>

commit 0a1754b2a97efa644aa6e84d1db5b17c42251483 upstream.

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;
...

Link: https://lkml.kernel.org/r/20201019142242.11560-1-hqjagain@gmail.com

Cc: stable@vger.kernel.org
Fixes: d60da506cbeb3 ("tracing: Add a resize function to make one buffer equivalent to another buffer")
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/trace/ring_buffer.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1625,18 +1625,18 @@ int ring_buffer_resize(struct ring_buffe
{
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);

@@ -1776,7 +1776,7 @@ int ring_buffer_resize(struct ring_buffe
}

mutex_unlock(&buffer->mutex);
- return size;
+ return 0;

out_err:
for_each_buffer_cpu(buffer, cpu) {