[src/trunk]: src/sys/net tun(4): Omit TUN_RWAIT micro-optimization.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6d65230a5f77
branches:  trunk
changeset: 363501:6d65230a5f77
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Mar 13 21:32:43 2022 +0000

description:
tun(4): Omit TUN_RWAIT micro-optimization.

cv_broadcast aleady has a fast path for no-waiters.

diffstat:

 sys/net/if_tun.c |  24 +++++-------------------
 sys/net/if_tun.h |   4 ++--
 2 files changed, 7 insertions(+), 21 deletions(-)

diffs (94 lines):

diff -r 5b3e4d2c59aa -r 6d65230a5f77 sys/net/if_tun.c
--- a/sys/net/if_tun.c  Sun Mar 13 21:32:35 2022 +0000
+++ b/sys/net/if_tun.c  Sun Mar 13 21:32:43 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_tun.c,v 1.169 2022/03/13 21:32:35 riastradh Exp $   */
+/*     $NetBSD: if_tun.c,v 1.170 2022/03/13 21:32:43 riastradh Exp $   */
 
 /*
  * Copyright (c) 1988, Julian Onions <jpo%cs.nott.ac.uk@localhost>
@@ -19,7 +19,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_tun.c,v 1.169 2022/03/13 21:32:35 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_tun.c,v 1.170 2022/03/13 21:32:43 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -330,10 +330,7 @@
        }
        mutex_exit(&tun_softc_lock);
 
-       if (tp->tun_flags & TUN_RWAIT) {
-               tp->tun_flags &= ~TUN_RWAIT;
-               cv_broadcast(&tp->tun_cv);
-       }
+       cv_broadcast(&tp->tun_cv);
        if (tp->tun_flags & TUN_ASYNC && tp->tun_pgid)
                fownsignal(tp->tun_pgid, SIGIO, POLL_HUP, 0, NULL);
        selnotify(&tp->tun_rsel, 0, NOTE_SUBMIT);
@@ -654,15 +651,10 @@
        }
 
        mutex_enter(&tp->tun_lock);
-       if (tp->tun_flags & TUN_RWAIT) {
-               tp->tun_flags &= ~TUN_RWAIT;
-               cv_broadcast(&tp->tun_cv);
-       }
+       cv_broadcast(&tp->tun_cv);
        if (tp->tun_flags & TUN_ASYNC && tp->tun_pgid)
                softint_schedule(tp->tun_isih);
-
        selnotify(&tp->tun_rsel, 0, NOTE_SUBMIT);
-
        mutex_exit(&tp->tun_lock);
 out:
        if (error && m0)
@@ -823,8 +815,6 @@
                goto out;
        }
 
-       tp->tun_flags &= ~TUN_RWAIT;
-
        do {
                IFQ_DEQUEUE(&ifp->if_snd, m0);
                if (m0 == 0) {
@@ -832,7 +822,6 @@
                                error = EWOULDBLOCK;
                                goto out;
                        }
-                       tp->tun_flags |= TUN_RWAIT;
                        if (cv_wait_sig(&tp->tun_cv, &tp->tun_lock)) {
                                error = EINTR;
                                goto out;
@@ -1024,10 +1013,7 @@
 
        mutex_enter(&tp->tun_lock);
        if (!IF_IS_EMPTY(&ifp->if_snd)) {
-               if (tp->tun_flags & TUN_RWAIT) {
-                       tp->tun_flags &= ~TUN_RWAIT;
-                       cv_broadcast(&tp->tun_cv);
-               }
+               cv_broadcast(&tp->tun_cv);
                if (tp->tun_flags & TUN_ASYNC && tp->tun_pgid)
                        softint_schedule(tp->tun_osih);
 
diff -r 5b3e4d2c59aa -r 6d65230a5f77 sys/net/if_tun.h
--- a/sys/net/if_tun.h  Sun Mar 13 21:32:35 2022 +0000
+++ b/sys/net/if_tun.h  Sun Mar 13 21:32:43 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_tun.h,v 1.21 2022/03/13 21:31:58 riastradh Exp $    */
+/*     $NetBSD: if_tun.h,v 1.22 2022/03/13 21:32:43 riastradh Exp $    */
 
 /*
  * Copyright (c) 1988, Julian Onions <jpo%cs.nott.ac.uk@localhost>
@@ -41,7 +41,7 @@
 #define        TUN_RCOLL       0x0004
 #define        TUN_IASET       0x0008
 #define        TUN_DSTADDR     0x0010
-#define        TUN_RWAIT       0x0040
+#define        TUN_UNUSED0     0x0040  /* was TUN_RWAIT */
 #define        TUN_ASYNC       0x0080
 #define        TUN_NBIO        0x0100
 #define        TUN_PREPADDR    0x0200