From 2489e958129ff7cbf26a34ee33cdc9ccbd68fe3c Mon Sep 17 00:00:00 2001
From: Jason Xing <kernelxing@tencent.com>
Date: Thu, 12 Jun 2025 14:11:57 +0800
Subject: [PATCH 4329/5403] relayfs: abolish prev_padding

Patch series "relayfs: misc changes", v5.

The series mostly focuses on the error counters which helps every user
debug their own kernel module.


This patch (of 5):

prev_padding represents the unused space of certain subbuffer.  If the
content of a call of relay_write() exceeds the limit of the remainder of
this subbuffer, it will skip storing in the rest space and record the
start point as buf->prev_padding in relay_switch_subbuf().  Since the buf
is a per-cpu big buffer, the point of prev_padding as a global value for
the whole buffer instead of a single subbuffer (whose padding info is
stored in buf->padding[]) seems meaningless from the real use cases, so we
don't bother to record it any more.

Link: https://lkml.kernel.org/r/20250612061201.34272-1-kerneljasonxing@gmail.com
Link: https://lkml.kernel.org/r/20250612061201.34272-2-kerneljasonxing@gmail.com
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Yushan Zhou <katrinzhou@tencent.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_log.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
index e8a04e476c57..09a64f224c49 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
@@ -220,8 +220,7 @@ static int guc_action_control_log(struct intel_guc *guc, bool enable,
  */
 static int subbuf_start_callback(struct rchan_buf *buf,
 				 void *subbuf,
-				 void *prev_subbuf,
-				 size_t prev_padding)
+				 void *prev_subbuf)
 {
 	/*
 	 * Use no-overwrite mode by default, where relay will stop accepting
-- 
2.54.0

