CVS commit: src/sys/kern

[Andrew Doran]

Module Name:    src
Committed By:   ad
Date:           Sat Jan 25 15:12:47 UTC 2020

Modified Files:
        src/sys/kern: kern_softint.c

Log Message:
softint_execute(): don't hang onto the kernel_lock hold longer than
needed.


To generate a diff of this commit:
cvs rdiff -u -r1.57 -r1.58 src/sys/kern/kern_softint.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/kern/kern_softint.c
diff -u src/sys/kern/kern_softint.c:1.57 src/sys/kern/kern_softint.c:1.58
--- src/sys/kern/kern_softint.c:1.57	Wed Jan  8 17:38:42 2020
+++ src/sys/kern/kern_softint.c	Sat Jan 25 15:12:47 2020
@@ -1,7 +1,7 @@
-/*	$NetBSD: kern_softint.c,v 1.57 2020/01/08 17:38:42 ad Exp $	*/
+/*	$NetBSD: kern_softint.c,v 1.58 2020/01/25 15:12:47 ad Exp $	*/
 
 /*-
- * Copyright (c) 2007, 2008, 2019 The NetBSD Foundation, Inc.
+ * Copyright (c) 2007, 2008, 2019, 2020 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * This code is derived from software contributed to The NetBSD Foundation
@@ -170,7 +170,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.57 2020/01/08 17:38:42 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.58 2020/01/25 15:12:47 ad Exp $");
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -544,7 +544,6 @@ static inline void
 softint_execute(softint_t *si, lwp_t *l, int s)
 {
 	softhand_t *sh;
-	bool havelock;
 
 #ifdef __HAVE_FAST_SOFTINTS
 	KASSERT(si->si_lwp == curlwp);
@@ -555,8 +554,6 @@ softint_execute(softint_t *si, lwp_t *l,
 	KASSERT(si->si_lwp->l_wchan == NULL);
 	KASSERT(si->si_active);
 
-	havelock = false;
-
 	/*
 	 * Note: due to priority inheritance we may have interrupted a
 	 * higher priority LWP.  Since the soft interrupt must be quick
@@ -577,17 +574,14 @@ softint_execute(softint_t *si, lwp_t *l,
 		splx(s);
 
 		/* Run the handler. */
-		if (sh->sh_flags & SOFTINT_MPSAFE) {
-			if (havelock) {
-				KERNEL_UNLOCK_ONE(l);
-				havelock = false;
-			}
-		} else if (!havelock) {
+		if (__predict_true((sh->sh_flags & SOFTINT_MPSAFE) != 0)) {
+			(*sh->sh_func)(sh->sh_arg);
+		} else {
 			KERNEL_LOCK(1, l);
-			havelock = true;
+			(*sh->sh_func)(sh->sh_arg);
+			KERNEL_UNLOCK_ONE(l);
 		}
-		(*sh->sh_func)(sh->sh_arg);
-
+		
 		/* Diagnostic: check that spin-locks have not leaked. */
 		KASSERTMSG(curcpu()->ci_mtx_count == 0,
 		    "%s: ci_mtx_count (%d) != 0, sh_func %p\n",
@@ -603,10 +597,6 @@ softint_execute(softint_t *si, lwp_t *l,
 
 	PSREF_DEBUG_BARRIER();
 
-	if (havelock) {
-		KERNEL_UNLOCK_ONE(l);
-	}
-
 	CPU_COUNT(CPU_COUNT_NSOFT, 1);
 
 	KASSERT(si->si_cpu == curcpu());