From 023542f48b57d6b785fcadb86ac336ae80653e58 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Tue, 15 Dec 2020 20:45:57 -0800 Subject: relay: allow the use of const callback structs None of the relay users require the use of mutable structs for callbacks, however the relay code does. Instead of assigning the default callback for subbuf_start, add a wrapper to conditionally call the client callback if available, and fall back to default behaviour otherwise. This lets all relay users make their struct rchan_callbacks const data. [jani.nikula@intel.com: cleanups, per Christoph] Link: https://lkml.kernel.org/r/20201124115412.32402-1-jani.nikula@intel.com Link: https://lkml.kernel.org/r/cc3ff292e4eb4fdc56bee3d690c7b8e39209cd37.1606153547.git.jani.nikula@intel.com Signed-off-by: Jani Nikula Reviewed-by: Christoph Hellwig Cc: Jens Axboe Cc: Kalle Valo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/relay.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/relay.h b/include/linux/relay.h index 99d024475ba5..72b876dd5cb8 100644 --- a/include/linux/relay.h +++ b/include/linux/relay.h @@ -62,7 +62,7 @@ struct rchan size_t subbuf_size; /* sub-buffer size */ size_t n_subbufs; /* number of sub-buffers per buffer */ size_t alloc_size; /* total buffer size allocated */ - struct rchan_callbacks *cb; /* client callbacks */ + const struct rchan_callbacks *cb; /* client callbacks */ struct kref kref; /* channel refcount */ void *private_data; /* for user-defined data */ size_t last_toobig; /* tried to log event > subbuf size */ @@ -157,7 +157,7 @@ struct rchan *relay_open(const char *base_filename, struct dentry *parent, size_t subbuf_size, size_t n_subbufs, - struct rchan_callbacks *cb, + const struct rchan_callbacks *cb, void *private_data); extern int relay_late_setup_files(struct rchan *chan, const char *base_filename, -- cgit v1.2.3-58-ga151