[src/trunk]: src/sys/dev/usb Do not hold the softc lock (IPL_SOFTUSB) unneces...

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

details:   https://anonhg.NetBSD.org/src/rev/6ca96a3035ad
branches:  trunk
changeset: 348066:6ca96a3035ad
user:      skrll <skrll%NetBSD.org@localhost>
date:      Mon Oct 03 13:36:33 2016 +0000

description:
Do not hold the softc lock (IPL_SOFTUSB) unnecessarily and specifically
across ucomparam (and the ucom_param method).  The method can sleep wait-
ing for transfers... any input/output will try to acquire the lock and get
stuck

diffstat:

 sys/dev/usb/ucom.c |  14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diffs (80 lines):

diff -r 4b0e5df1d30c -r 6ca96a3035ad sys/dev/usb/ucom.c
--- a/sys/dev/usb/ucom.c        Mon Oct 03 12:08:39 2016 +0000
+++ b/sys/dev/usb/ucom.c        Mon Oct 03 13:36:33 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ucom.c,v 1.113 2016/05/14 10:52:29 mlelstv Exp $       */
+/*     $NetBSD: ucom.c,v 1.114 2016/10/03 13:36:33 skrll Exp $ */
 
 /*
  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.113 2016/05/14 10:52:29 mlelstv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.114 2016/10/03 13:36:33 skrll Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -835,7 +835,9 @@
        }
 
        sc->sc_refcnt++;
+       mutex_exit(&sc->sc_lock);
        error = ucom_do_ioctl(sc, cmd, data, flag, l);
+       mutex_enter(&sc->sc_lock);
        if (--sc->sc_refcnt < 0)
                usb_detach_broadcast(sc->sc_dev, &sc->sc_detachcv);
        mutex_exit(&sc->sc_lock);
@@ -891,7 +893,9 @@
                break;
 
        case TIOCGFLAGS:
+               mutex_enter(&sc->sc_lock);
                *(int *)data = sc->sc_swflags;
+               mutex_exit(&sc->sc_lock);
                break;
 
        case TIOCSFLAGS:
@@ -899,7 +903,9 @@
                    KAUTH_DEVICE_TTY_PRIVSET, tp);
                if (error)
                        break;
+               mutex_enter(&sc->sc_lock);
                sc->sc_swflags = *(int *)data;
+               mutex_exit(&sc->sc_lock);
                break;
 
        case TIOCMSET:
@@ -947,6 +953,7 @@
        if (ISSET(ttybits, TIOCM_RTS))
                SET(combits, UMCR_RTS);
 
+       mutex_enter(&sc->sc_lock);
        switch (how) {
        case TIOCMBIC:
                CLR(sc->sc_mcr, combits);
@@ -961,6 +968,7 @@
                SET(sc->sc_mcr, combits);
                break;
        }
+       mutex_exit(&sc->sc_lock);
 
        if (how == TIOCMSET || ISSET(combits, UMCR_DTR))
                ucom_dtr(sc, (sc->sc_mcr & UMCR_DTR) != 0);
@@ -974,6 +982,7 @@
        u_char combits;
        int ttybits = 0;
 
+       mutex_enter(&sc->sc_lock);
        combits = sc->sc_mcr;
        if (ISSET(combits, UMCR_DTR))
                SET(ttybits, TIOCM_DTR);
@@ -995,6 +1004,7 @@
        if (sc->sc_ier != 0)
                SET(ttybits, TIOCM_LE);
 #endif
+       mutex_exit(&sc->sc_lock);
 
        return ttybits;
 }