[src/trunk]: src/sys/arch/xen/xen Allow a xbd to be detached from the domU (e...

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

details:   https://anonhg.NetBSD.org/src/rev/12e57d4089a6
branches:  trunk
changeset: 747576:12e57d4089a6
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Mon Sep 21 21:59:30 2009 +0000

description:
Allow a xbd to be detached from the domU (e.g. at shutdown). Patch tested
and adjusted by David Young, discussed on port-xen@ early august.

diffstat:

 sys/arch/xen/xen/xbd_xenbus.c |  49 +++++++++++++++++++++++++++++-------------
 1 files changed, 34 insertions(+), 15 deletions(-)

diffs (136 lines):

diff -r 6ef297d84e2d -r 12e57d4089a6 sys/arch/xen/xen/xbd_xenbus.c
--- a/sys/arch/xen/xen/xbd_xenbus.c     Mon Sep 21 19:41:23 2009 +0000
+++ b/sys/arch/xen/xen/xbd_xenbus.c     Mon Sep 21 21:59:30 2009 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xbd_xenbus.c,v 1.41 2009/07/29 12:02:10 cegger Exp $      */
+/*      $NetBSD: xbd_xenbus.c,v 1.42 2009/09/21 21:59:30 bouyer Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.41 2009/07/29 12:02:10 cegger Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.42 2009/09/21 21:59:30 bouyer Exp $");
 
 #include "opt_xen.h"
 #include "rnd.h"
@@ -110,6 +110,9 @@
 #define BLKIF_STATE_CONNECTED    1
 #define BLKIF_STATE_SUSPENDED    2
        int sc_shutdown;
+#define BLKIF_SHUTDOWN_RUN    0 /* no shutdown */
+#define BLKIF_SHUTDOWN_REMOTE 1 /* backend-initiated shutdown in progress */
+#define BLKIF_SHUTDOWN_LOCAL  2 /* locally-initiated shutdown in progress */
 
        uint64_t sc_sectors; /* number of sectors for this device */
        u_long sc_secsize; /* sector size */
@@ -140,8 +143,9 @@
 static int  xbd_map_align(struct xbd_req *);
 static void xbd_unmap_align(struct xbd_req *);
 
-CFATTACH_DECL_NEW(xbd, sizeof(struct xbd_xenbus_softc),
-   xbd_xenbus_match, xbd_xenbus_attach, xbd_xenbus_detach, NULL);
+CFATTACH_DECL3_NEW(xbd, sizeof(struct xbd_xenbus_softc),
+   xbd_xenbus_match, xbd_xenbus_attach, xbd_xenbus_detach, NULL, NULL, NULL,
+   DVF_DETACH_SHUTDOWN);
 
 dev_type_open(xbdopen);
 dev_type_close(xbdclose);
@@ -249,7 +253,7 @@
        }
 
        sc->sc_backend_status = BLKIF_STATE_DISCONNECTED;
-       sc->sc_shutdown = 1;
+       sc->sc_shutdown = BLKIF_SHUTDOWN_REMOTE;
        /* initialise shared structures and tell backend that we are ready */
        xbd_xenbus_resume(sc);
 
@@ -263,16 +267,31 @@
 xbd_xenbus_detach(device_t dev, int flags)
 {
        struct xbd_xenbus_softc *sc = device_private(dev);
-       int s, bmaj, cmaj, i, mn;
+       int bmaj, cmaj, i, mn, rc, s;
+
+       rc = disk_begindetach(&sc->sc_dksc.sc_dkdev, NULL, dev, flags);
+       if (rc != 0)
+               return rc;
+
        s = splbio();
        DPRINTF(("%s: xbd_detach\n", device_xname(dev)));
-       if (sc->sc_shutdown == 0) {
-               sc->sc_shutdown = 1;
+       if (sc->sc_shutdown == BLKIF_SHUTDOWN_RUN) {
+               sc->sc_shutdown = BLKIF_SHUTDOWN_LOCAL;
                /* wait for requests to complete */
                while (sc->sc_backend_status == BLKIF_STATE_CONNECTED &&
                    sc->sc_dksc.sc_dkdev.dk_stats->io_busy > 0)
                        tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach", hz/2);
+               xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateClosing);
        }
+       if ((flags & DETACH_FORCE) == 0) {
+               /* xbd_xenbus_detach already in progress */
+               wakeup(xbd_xenbus_detach);
+               splx(s);
+               return EALREADY;
+       }
+       while (xenbus_read_driver_state(sc->sc_xbusd->xbusd_otherend)
+           != XenbusStateClosed)
+               tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach2", hz/2);
        splx(s);
 
        /* locate the major number */
@@ -414,12 +433,12 @@
                break;
        case XenbusStateClosing:
                s = splbio();
-               sc->sc_shutdown = 1;
+               if (sc->sc_shutdown == BLKIF_SHUTDOWN_RUN)
+                       sc->sc_shutdown = BLKIF_SHUTDOWN_REMOTE;
                /* wait for requests to complete */
                while (sc->sc_backend_status == BLKIF_STATE_CONNECTED &&
                    sc->sc_dksc.sc_dkdev.dk_stats->io_busy > 0)
-                       tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach",
-                           hz/2);
+                       tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach", hz/2);
                splx(s);
                xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateClosed);
                break;
@@ -434,7 +453,7 @@
                        return;
 
                xbd_connect(sc);
-               sc->sc_shutdown = 0;
+               sc->sc_shutdown = BLKIF_SHUTDOWN_RUN;
                hypervisor_enable_event(sc->sc_evtchn);
 
                sc->sc_xbdsize =
@@ -635,7 +654,7 @@
        DPRINTF(("xbdstrategy(%p): b_bcount = %ld\n", bp,
            (long)bp->b_bcount));
 
-       if (sc == NULL || sc->sc_shutdown) {
+       if (sc == NULL || sc->sc_shutdown != BLKIF_SHUTDOWN_RUN) {
                bp->b_error = EIO;
                biodone(bp);
                return;
@@ -659,7 +678,7 @@
        DPRINTF(("xbdsize(%d)\n", dev));
 
        sc = device_lookup_private(&xbd_cd, DISKUNIT(dev));
-       if (sc == NULL || sc->sc_shutdown)
+       if (sc == NULL || sc->sc_shutdown != BLKIF_SHUTDOWN_RUN)
                return -1;
        return dk_size(sc->sc_di, &sc->sc_dksc, dev);
 }
@@ -750,7 +769,7 @@
        DPRINTF(("xbdstart(%p): b_bcount = %ld\n", bp, (long)bp->b_bcount));
 
        sc = device_lookup_private(&xbd_cd, DISKUNIT(bp->b_dev));
-       if (sc == NULL || sc->sc_shutdown) {
+       if (sc == NULL || sc->sc_shutdown != BLKIF_SHUTDOWN_RUN) {
                bp->b_error = EIO;
                goto err;
        }