From 10076ae01388caffec3b90abcce05f24a9e4b15e Mon Sep 17 00:00:00 2001 From: Leon Romanovsky Date: Tue, 1 Apr 2025 15:28:46 +0300 Subject: [PATCH] drivers/base: Extend documentation with preferred way to use auxbus Document the preferred way to use auxiliary bus. Signed-off-by: Leon Romanovsky Link: https://lore.kernel.org/r/206e8c249f630abd3661deb36b84b26282241040.1743510317.git.leon@kernel.org [ reworded the text a bit - gregkh ] Signed-off-by: Greg Kroah-Hartman --- drivers/base/auxiliary.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c index afa4df4c5a3f3..95717d509ca99 100644 --- a/drivers/base/auxiliary.c +++ b/drivers/base/auxiliary.c @@ -156,6 +156,16 @@ * }, * .ops = my_custom_ops, * }; + * + * Please note that such custom ops approach is valid, but it is hard to implement + * it right without global locks per-device to protect from auxiliary_drv removal + * during call to that ops. In addition, this implementation lacks proper module + * dependency, which causes to load/unload races between auxiliary parent and devices + * modules. + * + * The most easiest way to provide these ops reliably without needing to + * have a lock is to EXPORT_SYMBOL*() them and rely on already existing + * modules infrastructure for validity and correct dependencies chains. */ static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id, -- 2.39.5