Commit 57ebe910 authored Oct 19, 2020 by Qiujun Huang Committed by Greg Kroah-Hartman Nov 05, 2020

ring-buffer: Return 0 on success from ring_buffer_resize()

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: d60da506 ("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>

parent f8708955

kernel/trace/ring_buffer.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1692,18 +1692,18 @@ int ring_buffer_resize(struct ring_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);

		@@ -1843,7 +1843,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
		}

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

		out_err:
		for_each_buffer_cpu(buffer, cpu) {