[src/trunk]: src/sys/dev/usb fix umodem(4) detach:

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

details:   https://anonhg.NetBSD.org/src/rev/4ca77236f097
branches:  trunk
changeset: 455953:4ca77236f097
user:      mrg <mrg%NetBSD.org@localhost>
date:      Sat Apr 20 05:53:18 2019 +0000

description:
fix umodem(4) detach:

- ucom(4) needs kpreempt disabled around softint_schedule()
- switch a copied printf() to aprint_error_dev()
- use static normally in umodem_common.c
- remove unused sc_openings in softc, convert sc_dying to real bool
- add sc_refcnt, sc_lock and sc_detach_cv to softc.  usage is:
  - sc_dying is protected by sc_lock
  - sc_detach_cv is matched with sc_lock for cv operations
  - sc_refcnt is increased in open and decreased in close, any time
    it is decreased, it is checked for less than zero, and a broadcast
    performed on sc_detach_cv.  detach waits for sc_refcnt.
- umodem_param() and umodem_set() check for sc_dying

this fixes pullout out an open ucom@umodem.

@skrll.

XXX: pullup

diffstat:

 sys/dev/usb/ucom.c          |  16 ++++--
 sys/dev/usb/umodem_common.c |  92 +++++++++++++++++++++++++++++++++++---------
 sys/dev/usb/umodemvar.h     |   9 ++-
 3 files changed, 89 insertions(+), 28 deletions(-)

diffs (truncated from 332 to 300 lines):

diff -r 01c6903ee520 -r 4ca77236f097 sys/dev/usb/ucom.c
--- a/sys/dev/usb/ucom.c        Fri Apr 19 22:06:03 2019 +0000
+++ b/sys/dev/usb/ucom.c        Sat Apr 20 05:53:18 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ucom.c,v 1.121 2018/12/11 14:49:27 jakllsch Exp $      */
+/*     $NetBSD: ucom.c,v 1.122 2019/04/20 05:53:18 mrg Exp $   */
 
 /*
  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.121 2018/12/11 14:49:27 jakllsch Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ucom.c,v 1.122 2019/04/20 05:53:18 mrg Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -441,10 +441,8 @@
                        mutex_spin_exit(&tty_lock);
                }
                /* Wait for processes to go away. */
-               if (cv_timedwait(&sc->sc_detachcv, &sc->sc_lock, hz * 60)) {
-                       printf("%s: %s didn't detach\n", __func__,
-                           device_xname(sc->sc_dev));
-               }
+               if (cv_timedwait(&sc->sc_detachcv, &sc->sc_lock, hz * 60))
+                       aprint_error_dev(self, ": didn't detach\n");
        }
 
        softint_disestablish(sc->sc_si);
@@ -1271,7 +1269,9 @@
 
        if (old && !block) {
                sc->sc_rx_unblock = 1;
+               kpreempt_disable();
                softint_schedule(sc->sc_si);
+               kpreempt_enable();
        }
        mutex_exit(&sc->sc_lock);
 
@@ -1339,7 +1339,9 @@
 
        SIMPLEQ_INSERT_TAIL(&sc->sc_obuff_full, ub, ub_link);
 
+       kpreempt_disable();
        softint_schedule(sc->sc_si);
+       kpreempt_enable();
 
  out:
        DPRINTF("... done", 0, 0, 0, 0);
@@ -1381,7 +1383,9 @@
                break;
        case USBD_STALLED:
                ub->ub_index = 0;
+               kpreempt_disable();
                softint_schedule(sc->sc_si);
+               kpreempt_enable();
                break;
        case USBD_NORMAL_COMPLETION:
                usbd_get_xfer_status(ub->ub_xfer, NULL, NULL, &cc, NULL);
diff -r 01c6903ee520 -r 4ca77236f097 sys/dev/usb/umodem_common.c
--- a/sys/dev/usb/umodem_common.c       Fri Apr 19 22:06:03 2019 +0000
+++ b/sys/dev/usb/umodem_common.c       Sat Apr 20 05:53:18 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: umodem_common.c,v 1.26 2019/01/04 17:09:26 tih Exp $   */
+/*     $NetBSD: umodem_common.c,v 1.27 2019/04/20 05:53:18 mrg Exp $   */
 
 /*
  * Copyright (c) 1998 The NetBSD Foundation, Inc.
@@ -44,7 +44,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: umodem_common.c,v 1.26 2019/01/04 17:09:26 tih Exp $");
+__KERNEL_RCSID(0, "$NetBSD: umodem_common.c,v 1.27 2019/04/20 05:53:18 mrg Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -94,16 +94,16 @@
 #define UMODEMIBUFSIZE 4096
 #define UMODEMOBUFSIZE 4096
 
-Static usbd_status umodem_set_comm_feature(struct umodem_softc *,
+static usbd_status umodem_set_comm_feature(struct umodem_softc *,
                                           int, int);
-Static usbd_status umodem_set_line_coding(struct umodem_softc *,
+static usbd_status umodem_set_line_coding(struct umodem_softc *,
                                          usb_cdc_line_state_t *);
 
-Static void    umodem_dtr(struct umodem_softc *, int);
-Static void    umodem_rts(struct umodem_softc *, int);
-Static void    umodem_break(struct umodem_softc *, int);
-Static void    umodem_set_line_state(struct umodem_softc *);
-Static void    umodem_intr(struct usbd_xfer *, void *, usbd_status);
+static void    umodem_dtr(struct umodem_softc *, int);
+static void    umodem_rts(struct umodem_softc *, int);
+static void    umodem_break(struct umodem_softc *, int);
+static void    umodem_set_line_state(struct umodem_softc *);
+static void    umodem_intr(struct usbd_xfer *, void *, usbd_status);
 
 int
 umodem_common_attach(device_t self, struct umodem_softc *sc,
@@ -120,10 +120,15 @@
        sc->sc_dev = self;
        sc->sc_udev = dev;
        sc->sc_ctl_iface = uiaa->uiaa_iface;
+       sc->sc_refcnt = 0;
+       sc->sc_dying = false;
 
        aprint_naive("\n");
        aprint_normal("\n");
 
+       mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_SOFTUSB);
+       cv_init(&sc->sc_detach_cv, "umodemdet");
+
        id = usbd_get_interface_descriptor(sc->sc_ctl_iface);
        devinfop = usbd_devinfo_alloc(uiaa->uiaa_device, 0);
        aprint_normal_dev(self, "%s, iclass %d/%d\n",
@@ -256,7 +261,7 @@
        return 0;
 
  bad:
-       sc->sc_dying = 1;
+       sc->sc_dying = true;
        return 1;
 }
 
@@ -266,6 +271,15 @@
        struct umodem_softc *sc = addr;
        int err;
 
+       mutex_enter(&sc->sc_lock);
+       if (sc->sc_dying) {
+               mutex_exit(&sc->sc_lock);
+               return EIO;
+       }
+
+       sc->sc_refcnt++;
+       mutex_exit(&sc->sc_lock);
+
        DPRINTF(("umodem_open: sc=%p\n", sc));
 
        if (sc->sc_ctl_notify != -1 && sc->sc_notify_pipe == NULL) {
@@ -277,6 +291,10 @@
                if (err) {
                        DPRINTF(("Failed to establish notify pipe: %s\n",
                                usbd_errstr(err)));
+                       mutex_enter(&sc->sc_lock);
+                       if (--sc->sc_refcnt < 0)
+                               cv_broadcast(&sc->sc_detach_cv);
+                       mutex_exit(&sc->sc_lock);
                        return EIO;
                }
        }
@@ -290,6 +308,11 @@
        struct umodem_softc *sc = addr;
        int err;
 
+       mutex_enter(&sc->sc_lock);
+       if (sc->sc_dying)
+               goto out;
+       mutex_exit(&sc->sc_lock);
+
        DPRINTF(("umodem_close: sc=%p\n", sc));
 
        if (sc->sc_notify_pipe != NULL) {
@@ -303,9 +326,15 @@
                            device_xname(sc->sc_dev), usbd_errstr(err));
                sc->sc_notify_pipe = NULL;
        }
+
+       mutex_enter(&sc->sc_lock);
+out:
+       if (--sc->sc_refcnt < 0)
+               cv_broadcast(&sc->sc_detach_cv);
+       mutex_exit(&sc->sc_lock);
 }
 
-Static void
+static void
 umodem_intr(struct usbd_xfer *xfer, void *priv,
     usbd_status status)
 {
@@ -438,6 +467,11 @@
        usbd_status err;
        usb_cdc_line_state_t ls;
 
+       mutex_enter(&sc->sc_lock);
+       if (sc->sc_dying)
+               return EIO;
+       mutex_exit(&sc->sc_lock);
+
        DPRINTF(("umodem_param: sc=%p\n", sc));
 
        USETDW(ls.dwDTERate, t->c_ospeed);
@@ -482,8 +516,10 @@
        struct umodem_softc *sc = addr;
        int error = 0;
 
+       mutex_enter(&sc->sc_lock);
        if (sc->sc_dying)
                return EIO;
+       mutex_exit(&sc->sc_lock);
 
        DPRINTF(("umodem_ioctl: cmd=0x%08lx\n", cmd));
 
@@ -507,7 +543,7 @@
        return error;
 }
 
-void
+static void
 umodem_dtr(struct umodem_softc *sc, int onoff)
 {
        DPRINTF(("umodem_dtr: onoff=%d\n", onoff));
@@ -519,7 +555,7 @@
        umodem_set_line_state(sc);
 }
 
-void
+static void
 umodem_rts(struct umodem_softc *sc, int onoff)
 {
        DPRINTF(("umodem_rts: onoff=%d\n", onoff));
@@ -531,7 +567,7 @@
        umodem_set_line_state(sc);
 }
 
-void
+static void
 umodem_set_line_state(struct umodem_softc *sc)
 {
        usb_device_request_t req;
@@ -549,7 +585,7 @@
 
 }
 
-void
+static void
 umodem_break(struct umodem_softc *sc, int onoff)
 {
        usb_device_request_t req;
@@ -573,6 +609,11 @@
 {
        struct umodem_softc *sc = addr;
 
+       mutex_enter(&sc->sc_lock);
+       if (sc->sc_dying)
+               return;
+       mutex_exit(&sc->sc_lock);
+
        switch (reg) {
        case UCOM_SET_DTR:
                umodem_dtr(sc, onoff);
@@ -588,7 +629,7 @@
        }
 }
 
-usbd_status
+static usbd_status
 umodem_set_line_coding(struct umodem_softc *sc, usb_cdc_line_state_t *state)
 {
        usb_device_request_t req;
@@ -621,7 +662,7 @@
        return USBD_NORMAL_COMPLETION;
 }
 
-usbd_status
+static usbd_status
 umodem_set_comm_feature(struct umodem_softc *sc, int feature, int state)
 {
        usb_device_request_t req;
@@ -653,7 +694,9 @@
 {
        switch (act) {
        case DVACT_DEACTIVATE:
-               sc->sc_dying = 1;
+               mutex_enter(&sc->sc_lock);
+               sc->sc_dying = true;
+               mutex_exit(&sc->sc_lock);
                return 0;
        default:
                return EOPNOTSUPP;
@@ -674,12 +717,23 @@
 
        DPRINTF(("umodem_common_detach: sc=%p flags=%d\n", sc, flags));
 
-       sc->sc_dying = 1;
+       mutex_enter(&sc->sc_lock);
+       sc->sc_dying = true;
+
+       sc->sc_refcnt--;
+       while (sc->sc_refcnt > 0) {
+               if (cv_timedwait(&sc->sc_detach_cv, &sc->sc_lock, hz * 60))
+                       aprint_error_dev(sc->sc_dev, ": didn't detach\n");
+       }
+       mutex_exit(&sc->sc_lock);
 
        if (sc->sc_subdev != NULL)