From 42fb0a1e84ff525ebe560e2baf9451ab69127e2b Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Thu, 20 Oct 2022 23:14:27 -0400 Subject: tracing/ring-buffer: Have polling block on watermark Currently the way polling works on the ring buffer is broken. It will return immediately if there's any data in the ring buffer whereas a read will block until the watermark (defined by the tracefs buffer_percent file) is hit. That is, a select() or poll() will return as if there's data available, but then the following read will block. This is broken for the way select()s and poll()s are supposed to work. Have the polling on the ring buffer also block the same way reads and splice does on the ring buffer. Link: https://lkml.kernel.org/r/20221020231427.41be3f26@gandalf.local.home Cc: Linux Trace Kernel Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Primiano Tucci Cc: stable@vger.kernel.org Fixes: 1e0d6714aceb7 ("ring-buffer: Do not wake up a splice waiter when page is not full") Signed-off-by: Steven Rostedt (Google) --- include/linux/ring_buffer.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index 2504df9a0453..3c7d295746f6 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -100,7 +100,7 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full); __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, - struct file *filp, poll_table *poll_table); + struct file *filp, poll_table *poll_table, int full); void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu); #define RING_BUFFER_ALL_CPUS -1 -- cgit v1.2.3-70-g09d2