[src/trunk]: src/sys/dev/dkwedge dk(4): Omit redundant microoptimization arou...

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

details:   https://anonhg.NetBSD.org/src/rev/1c16683b4434
branches:  trunk
changeset: 359662:1c16683b4434
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Jan 15 19:34:11 2022 +0000

description:
dk(4): Omit redundant microoptimization around cv_broadcast.

cv_broadcast already has a fast path for the no-waiter case.

diffstat:

 sys/dev/dkwedge/dk.c |  20 +++++---------------
 1 files changed, 5 insertions(+), 15 deletions(-)

diffs (68 lines):

diff -r 6857d0612df6 -r 1c16683b4434 sys/dev/dkwedge/dk.c
--- a/sys/dev/dkwedge/dk.c      Sat Jan 15 19:34:07 2022 +0000
+++ b/sys/dev/dkwedge/dk.c      Sat Jan 15 19:34:11 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: dk.c,v 1.109 2021/10/18 11:40:56 simonb Exp $  */
+/*     $NetBSD: dk.c,v 1.110 2022/01/15 19:34:11 riastradh Exp $       */
 
 /*-
  * Copyright (c) 2004, 2005, 2006, 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.109 2021/10/18 11:40:56 simonb Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.110 2022/01/15 19:34:11 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_dkwedge.h"
@@ -89,12 +89,9 @@
        kmutex_t        sc_iolock;
        kcondvar_t      sc_dkdrn;
        u_int           sc_iopend;      /* I/Os pending */
-       int             sc_flags;       /* flags (sc_iolock) */
        int             sc_mode;        /* parent open mode */
 };
 
-#define        DK_F_WAIT_DRAIN         0x0001  /* waiting for I/O to drain */
-
 static void    dkstart(struct dkwedge_softc *);
 static void    dkiodone(struct buf *);
 static void    dkrestart(void *);
@@ -194,10 +191,8 @@
 {
 
        mutex_enter(&sc->sc_iolock);
-       while (sc->sc_iopend != 0) {
-               sc->sc_flags |= DK_F_WAIT_DRAIN;
+       while (sc->sc_iopend != 0)
                cv_wait(&sc->sc_dkdrn, &sc->sc_iolock);
-       }
        mutex_exit(&sc->sc_iolock);
 }
 
@@ -1341,11 +1336,8 @@
        while ((bp = bufq_peek(sc->sc_bufq)) != NULL) {
                if (sc->sc_state != DKW_STATE_RUNNING) {
                        (void) bufq_get(sc->sc_bufq);
-                       if (sc->sc_iopend-- == 1 &&
-                           (sc->sc_flags & DK_F_WAIT_DRAIN) != 0) {
-                               sc->sc_flags &= ~DK_F_WAIT_DRAIN;
+                       if (--sc->sc_iopend == 0)
                                cv_broadcast(&sc->sc_dkdrn);
-                       }
                        mutex_exit(&sc->sc_iolock);
                        bp->b_error = ENXIO;
                        bp->b_resid = bp->b_bcount;
@@ -1430,10 +1422,8 @@
        putiobuf(bp);
 
        mutex_enter(&sc->sc_iolock);
-       if (sc->sc_iopend-- == 1 && (sc->sc_flags & DK_F_WAIT_DRAIN) != 0) {
-               sc->sc_flags &= ~DK_F_WAIT_DRAIN;
+       if (--sc->sc_iopend == 0)
                cv_broadcast(&sc->sc_dkdrn);
-       }
 
        disk_unbusy(&sc->sc_dk, obp->b_bcount - obp->b_resid,
            obp->b_flags & B_READ);