git: 40e9da8c6b64 - stable/13 - rmlock: Add required compiler barriers to _rm_runlock()

From: Mark Johnston <markj_at_FreeBSD.org>
Date: Mon, 14 Mar 2022 14:46:04 UTC
The branch stable/13 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=40e9da8c6b6453f7a26737c64e3de9da11f9f8a4

commit 40e9da8c6b6453f7a26737c64e3de9da11f9f8a4
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2022-03-01 13:55:43 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2022-03-14 14:45:06 +0000

    rmlock: Add required compiler barriers to _rm_runlock()
    
    Also remove excessive whitespace in _rm_rlock().
    
    Reviewed by:    jah, mjg
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit 89ae8eb74e87ac19aa2d7abe4ba16bcccd32bb9f)
---
 sys/kern/kern_rmlock.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sys/kern/kern_rmlock.c b/sys/kern/kern_rmlock.c
index 66a035554b17..d7dea8efc40e 100644
--- a/sys/kern/kern_rmlock.c
+++ b/sys/kern/kern_rmlock.c
@@ -449,17 +449,13 @@ _rm_rlock(struct rmlock *rm, struct rm_priotracker *tracker, int trylock)
 		THREAD_NO_SLEEPING();
 
 	td->td_critnest++;	/* critical_enter(); */
-
 	atomic_interrupt_fence();
 
 	pc = cpuid_to_pcpu[td->td_oncpu];
-
 	rm_tracker_add(pc, tracker);
-
 	sched_pin();
 
 	atomic_interrupt_fence();
-
 	td->td_critnest--;
 
 	/*
@@ -517,8 +513,12 @@ _rm_runlock(struct rmlock *rm, struct rm_priotracker *tracker)
 		return;
 
 	td->td_critnest++;	/* critical_enter(); */
+	atomic_interrupt_fence();
+
 	pc = cpuid_to_pcpu[td->td_oncpu];
 	rm_tracker_remove(pc, tracker);
+
+	atomic_interrupt_fence();
 	td->td_critnest--;
 	sched_unpin();