From 0a1754b2a97efa644aa6e84d1db5b17c42251483 Mon Sep 17 00:00:00 2001 From: Qiujun Huang Date: Mon, 19 Oct 2020 22:22:42 +0800 Subject: ring-buffer: Return 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; ... 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 Signed-off-by: Steven Rostedt (VMware) --- 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 15bf28b13e50..5c6a9c6a058f 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) { -- cgit From e1981f75d398c0afe83c8ffa4e5864f037967409 Mon Sep 17 00:00:00 2001 From: Qiujun Huang Date: Sat, 17 Oct 2020 17:52:46 +0800 Subject: ring-buffer: Update the description for ring_buffer_wait The function changed at some point, but the description was not updated. Link: https://lkml.kernel.org/r/20201017095246.5170-1-hqjagain@gmail.com Signed-off-by: Qiujun Huang Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 5c6a9c6a058f..7f45fd9d5a45 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -793,7 +793,7 @@ static void rb_wake_up_waiters(struct irq_work *work) * ring_buffer_wait - wait for input to the ring buffer * @buffer: buffer to wait on * @cpu: the cpu buffer to wait on - * @full: wait until a full page is available, if @cpu != RING_BUFFER_ALL_CPUS + * @full: wait until the percentage of pages are available, if @cpu != RING_BUFFER_ALL_CPUS * * If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon * as data is added to any of the @buffer's cpu buffers. Otherwise -- cgit