Make dksubr use a spin-mutex again, since some drivers still call dk_done
from hardware interrupt. Instead, release mutex while calling start routine. The buffer peek/use/get sequence which can no longer be atomic. So consume the buffer directly and on error privately save and retry the buffer later. The dk_drain function is used to flush such a deferred buffer together with the buffer queue. Adjust drivers to use dk_drain. Fix an error path where dk_done was called while the lock was already held.
This commit is contained in:
mlelstv
parent
d6cc60697d
commit
7874349bce
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@ -1,4 +1,4 @@
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/* $NetBSD: xbd_xenbus.c,v 1.72 2015/08/16 18:00:03 mlelstv Exp $ */
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/* $NetBSD: xbd_xenbus.c,v 1.73 2015/08/27 05:51:50 mlelstv Exp $ */
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/*
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* Copyright (c) 2006 Manuel Bouyer.
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@ -50,7 +50,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.72 2015/08/16 18:00:03 mlelstv Exp $");
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__KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.73 2015/08/27 05:51:50 mlelstv Exp $");
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#include "opt_xen.h"
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@ -363,11 +363,9 @@ xbd_xenbus_detach(device_t dev, int flags)
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/* Delete all of our wedges. */
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dkwedge_delall(&sc->sc_dksc.sc_dkdev);
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s = splbio();
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/* Kill off any queued buffers. */
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bufq_drain(sc->sc_dksc.sc_bufq);
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dk_drain(&sc->sc_dksc);
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bufq_free(sc->sc_dksc.sc_bufq);
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splx(s);
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/* detach disk */
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disk_detach(&sc->sc_dksc.sc_dkdev);
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@ -701,12 +699,11 @@ again:
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next:
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if (bp->b_data != xbdreq->req_data)
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xbd_unmap_align(xbdreq);
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disk_unbusy(&sc->sc_dksc.sc_dkdev,
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(bp->b_bcount - bp->b_resid),
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(bp->b_flags & B_READ));
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rnd_add_uint32(&sc->sc_rnd_source,
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bp->b_blkno);
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biodone(bp);
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dk_done(&sc->sc_dksc, bp);
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SLIST_INSERT_HEAD(&sc->sc_xbdreq_head, xbdreq, req_next);
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}
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done:
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@ -1,4 +1,4 @@
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/* $NetBSD: cgd.c,v 1.103 2015/08/21 09:33:53 christos Exp $ */
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/* $NetBSD: cgd.c,v 1.104 2015/08/27 05:51:50 mlelstv Exp $ */
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/*-
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* Copyright (c) 2002 The NetBSD Foundation, Inc.
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@ -30,7 +30,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.103 2015/08/21 09:33:53 christos Exp $");
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__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.104 2015/08/27 05:51:50 mlelstv Exp $");
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#include <sys/types.h>
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#include <sys/param.h>
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@ -565,7 +565,7 @@ cgdioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
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return VOP_IOCTL(cs->sc_tvn, cmd, data, flag, l->l_cred);
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case DIOCGSTRATEGY:
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case DIOCSSTRATEGY:
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if ((dksc->sc_flags & DKF_INITED) == 0)
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if (!DK_ATTACHED(dksc))
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return ENOENT;
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/*FALLTHROUGH*/
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default:
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@ -722,7 +722,6 @@ bail:
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static int
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cgd_ioctl_clr(struct cgd_softc *cs, struct lwp *l)
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{
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int s;
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struct dk_softc *dksc = &cs->sc_dksc;
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if (!DK_ATTACHED(dksc))
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@ -732,9 +731,7 @@ cgd_ioctl_clr(struct cgd_softc *cs, struct lwp *l)
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dkwedge_delall(&dksc->sc_dkdev);
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/* Kill off any queued buffers. */
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s = splbio();
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bufq_drain(dksc->sc_bufq);
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splx(s);
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dk_drain(dksc);
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bufq_free(dksc->sc_bufq);
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(void)vn_close(cs->sc_tvn, FREAD|FWRITE, l->l_cred);
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@ -1,4 +1,4 @@
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/* $NetBSD: dksubr.c,v 1.73 2015/08/23 07:47:52 mlelstv Exp $ */
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/* $NetBSD: dksubr.c,v 1.74 2015/08/27 05:51:50 mlelstv Exp $ */
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/*-
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* Copyright (c) 1996, 1997, 1998, 1999, 2002, 2008 The NetBSD Foundation, Inc.
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@ -30,7 +30,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.73 2015/08/23 07:47:52 mlelstv Exp $");
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__KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.74 2015/08/27 05:51:50 mlelstv Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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@ -74,6 +74,7 @@ static int dk_subr_modcmd(modcmd_t, void *);
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static void dk_makedisklabel(struct dk_softc *);
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static int dk_translate(struct dk_softc *, struct buf *);
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static void dk_done1(struct dk_softc *, struct buf *, bool);
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void
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dk_init(struct dk_softc *dksc, device_t dev, int dtype)
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@ -90,7 +91,7 @@ dk_init(struct dk_softc *dksc, device_t dev, int dtype)
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void
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dk_attach(struct dk_softc *dksc)
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{
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mutex_init(&dksc->sc_iolock, MUTEX_DEFAULT, IPL_NONE);
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mutex_init(&dksc->sc_iolock, MUTEX_DEFAULT, IPL_VM);
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dksc->sc_flags |= DKF_INITED;
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#ifdef DIAGNOSTIC
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dksc->sc_flags |= DKF_WARNLABEL | DKF_LABELSANITY;
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@ -294,41 +295,55 @@ dk_start(struct dk_softc *dksc, struct buf *bp)
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{
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const struct dkdriver *dkd = dksc->sc_dkdev.dk_driver;
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int error;
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struct buf *qbp __diagused;
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mutex_enter(&dksc->sc_iolock);
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if (bp != NULL)
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bufq_put(dksc->sc_bufq, bp);
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while ((bp = bufq_peek(dksc->sc_bufq)) != NULL) {
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/*
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* Peeking at the buffer queue and committing the operation
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* only after success isn't atomic.
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*
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* So when a diskstart fails, the buffer is saved
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* and tried again before the next buffer is fetched.
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* dk_drain() handles flushing of a saved buffer.
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*
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* This keeps order of I/O operations, unlike bufq_put.
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*/
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bp = dksc->sc_deferred;
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dksc->sc_deferred = NULL;
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if (bp == NULL)
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bp = bufq_get(dksc->sc_bufq);
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while (bp != NULL) {
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disk_busy(&dksc->sc_dkdev);
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mutex_exit(&dksc->sc_iolock);
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error = dkd->d_diskstart(dksc->sc_dev, bp);
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mutex_enter(&dksc->sc_iolock);
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if (error == EAGAIN) {
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dksc->sc_deferred = bp;
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disk_unbusy(&dksc->sc_dkdev, 0, (bp->b_flags & B_READ));
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break;
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}
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#ifdef DIAGNOSTIC
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qbp = bufq_get(dksc->sc_bufq);
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KASSERT(bp == qbp);
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#else
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(void) bufq_get(dksc->sc_bufq);
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#endif
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if (error != 0) {
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bp->b_error = error;
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bp->b_resid = bp->b_bcount;
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dk_done(dksc, bp);
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dk_done1(dksc, bp, false);
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}
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bp = bufq_get(dksc->sc_bufq);
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}
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mutex_exit(&dksc->sc_iolock);
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}
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void
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dk_done(struct dk_softc *dksc, struct buf *bp)
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static void
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dk_done1(struct dk_softc *dksc, struct buf *bp, bool lock)
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{
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struct disk *dk = &dksc->sc_dkdev;
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printf("\n");
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}
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mutex_enter(&dksc->sc_iolock);
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if (lock)
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mutex_enter(&dksc->sc_iolock);
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disk_unbusy(dk, bp->b_bcount - bp->b_resid, (bp->b_flags & B_READ));
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mutex_exit(&dksc->sc_iolock);
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if (lock)
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mutex_exit(&dksc->sc_iolock);
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#ifdef notyet
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rnd_add_uint(&dksc->sc_rnd_source, bp->b_rawblkno);
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biodone(bp);
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}
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void
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dk_done(struct dk_softc *dksc, struct buf *bp)
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{
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dk_done1(dksc, bp, true);
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}
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void
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dk_drain(struct dk_softc *dksc)
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{
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struct buf *bp;
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mutex_enter(&dksc->sc_iolock);
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bp = dksc->sc_deferred;
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if (bp != NULL) {
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bp->b_error = EIO;
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bp->b_resid = bp->b_bcount;
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biodone(bp);
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}
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bufq_drain(dksc->sc_bufq);
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mutex_exit(&dksc->sc_iolock);
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}
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int
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dk_discard(struct dk_softc *dksc, dev_t dev, off_t pos, off_t len)
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{
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@ -1,4 +1,4 @@
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/* $NetBSD: dkvar.h,v 1.21 2015/08/16 18:00:03 mlelstv Exp $ */
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/* $NetBSD: dkvar.h,v 1.22 2015/08/27 05:51:50 mlelstv Exp $ */
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/*-
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* Copyright (c) 2002 The NetBSD Foundation, Inc.
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@ -47,6 +47,7 @@ struct dk_softc {
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kmutex_t sc_iolock; /* protects buffer queue */
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struct bufq_state *sc_bufq; /* buffer queue */
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int sc_dtype; /* disk type */
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struct buf *sc_deferred; /* retry after start failed */
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};
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/* sc_flags:
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@ -62,6 +63,7 @@ struct dk_softc {
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#define DKF_TAKEDUMP 0x00200000 /* allow dumping */
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#define DKF_KLABEL 0x00400000 /* keep label on close */
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#define DKF_VLABEL 0x00800000 /* label is valid */
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#define DKF_SLEEP 0x80000000 /* dk_start/dk_done may sleep */
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/* Mask of flags that dksubr.c understands, other flags are fair game */
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#define DK_FLAGMASK 0xffff0000
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@ -89,6 +91,7 @@ void dk_strategy(struct dk_softc *, struct buf *);
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int dk_discard(struct dk_softc *, dev_t, off_t, off_t);
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void dk_start(struct dk_softc *, struct buf *);
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void dk_done(struct dk_softc *, struct buf *);
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void dk_drain(struct dk_softc *);
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int dk_size(struct dk_softc *, dev_t);
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int dk_ioctl(struct dk_softc *, dev_t,
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u_long, void *, int, struct lwp *);
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13
sys/dev/ld.c
13
sys/dev/ld.c
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@ -1,4 +1,4 @@
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/* $NetBSD: ld.c,v 1.91 2015/08/18 04:20:25 mlelstv Exp $ */
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/* $NetBSD: ld.c,v 1.92 2015/08/27 05:51:50 mlelstv Exp $ */
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/*-
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* Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
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@ -34,7 +34,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: ld.c,v 1.91 2015/08/18 04:20:25 mlelstv Exp $");
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__KERNEL_RCSID(0, "$NetBSD: ld.c,v 1.92 2015/08/27 05:51:50 mlelstv Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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@ -197,8 +197,6 @@ ldbegindetach(struct ld_softc *sc, int flags)
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mutex_enter(&sc->sc_mutex);
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sc->sc_maxqueuecnt = 0;
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dk_detach(dksc);
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while (sc->sc_queuecnt > 0) {
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sc->sc_flags |= LDF_DRAIN;
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cv_wait(&sc->sc_drain, &sc->sc_mutex);
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@ -224,11 +222,10 @@ ldenddetach(struct ld_softc *sc)
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if (cv_timedwait(&sc->sc_drain, &sc->sc_mutex, 30 * hz))
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printf("%s: not drained\n", dksc->sc_xname);
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}
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/* Kill off any queued buffers. */
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bufq_drain(dksc->sc_bufq);
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mutex_exit(&sc->sc_mutex);
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/* Kill off any queued buffers. */
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dk_drain(dksc);
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bufq_free(dksc->sc_bufq);
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/* Locate the major numbers. */
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@ -249,6 +246,8 @@ ldenddetach(struct ld_softc *sc)
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disk_detach(&dksc->sc_dkdev);
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disk_destroy(&dksc->sc_dkdev);
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dk_detach(dksc);
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/* Unhook the entropy source. */
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rnd_detach_source(&sc->sc_rnd_source);
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