From 2489e958129ff7cbf26a34ee33cdc9ccbd68fe3c Mon Sep 17 00:00:00 2001 From: Jason Xing Date: Thu, 12 Jun 2025 14:11:57 +0800 Subject: 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 Reviewed-by: Yushan Zhou Reviewed-by: Masami Hiramatsu (Google) Cc: Jens Axboe Cc: Mathieu Desnoyers Cc: Steven Rostedt Signed-off-by: Andrew Morton --- include/linux/relay.h | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/relay.h b/include/linux/relay.h index b3224111d074..e10a0fdf4325 100644 --- a/include/linux/relay.h +++ b/include/linux/relay.h @@ -47,7 +47,6 @@ struct rchan_buf unsigned int page_count; /* number of current buffer pages */ unsigned int finalized; /* buffer has been finalized */ size_t *padding; /* padding counts per sub-buffer */ - size_t prev_padding; /* temporary variable */ size_t bytes_consumed; /* bytes consumed in cur read subbuf */ size_t early_bytes; /* bytes consumed before VFS inited */ unsigned int cpu; /* this buf's cpu */ @@ -84,7 +83,6 @@ struct rchan_callbacks * @buf: the channel buffer containing the new sub-buffer * @subbuf: the start of the new sub-buffer * @prev_subbuf: the start of the previous sub-buffer - * @prev_padding: unused space at the end of previous sub-buffer * * The client should return 1 to continue logging, 0 to stop * logging. @@ -100,8 +98,7 @@ struct rchan_callbacks */ int (*subbuf_start) (struct rchan_buf *buf, void *subbuf, - void *prev_subbuf, - size_t prev_padding); + void *prev_subbuf); /* * create_buf_file - create file to represent a relay channel buffer -- cgit v1.2.3