Rename the kld_unload event handler to kld_unload_try, and add a new

kld_unload event handler which gets invoked after a linker file has been
successfully unloaded. The kld_unload and kld_load event handlers are now
invoked with the shared linker lock held, while kld_unload_try is invoked
with the lock exclusively held.

Convert hwpmc(4) to use these event handlers instead of having
kern_kldload() and kern_kldunload() invoke hwpmc(4) hooks whenever files are
loaded or unloaded. This has no functional effect, but simplifes the linker
code somewhat.

Reviewed by:	jhb

1 files changed, 2 insertions, 0 deletions

diff --git a/share/man/man9/EVENTHANDLER.9 b/share/man/man9/EVENTHANDLER.9
index c3b646d985b4..d6e75562c9c8 100644
--- a/share/man/man9/EVENTHANDLER.9
+++ b/share/man/man9/EVENTHANDLER.9
@@ -202,6 +202,8 @@ Callbacks invoked when a BPF listener attaches to/detaches from network interfac
 .It Vt kld_load
 Callbacks invoked after a linker file has been loaded.
 .It Vt kld_unload
+Callbacks invoked after a linker file has been successfully unloaded.
+.It Vt kld_unload_try
 Callbacks invoked before a linker file is about to be unloaded.
 These callbacks may be used to return an error and prevent the unload from
 proceeding.