[PATCH next 1/2] drivers/base: Extend documentation with preferred way to use auxbus

[Leon Romanovsky <leon@kernel.org>]

Document the preferred way to use auxiliary bus.

Signed-off-by: Leon Romanovsky <leon@kernel.org>
---
 drivers/base/auxiliary.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c
index afa4df4c5a3f..248d3508ca0e 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 whtout need to have 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,
-- 
2.48.1