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dk(4): Omit needless sc_iopend, sc_dkdrn mechanism. 

vdevgone guarantees that all instances are closed by the time it
returns, which in turn guarantees all I/O operations (read, write,
ioctl, &c.) have completed, and, if the block device is open,
vinvalbuf(V_SAVE) -> vflushbuf has completed, which forces all
buffered transfers to be issued and waits for them to complete.

So by the time vdevgone returns, no further transfers can be
submitted and the bufq must be empty.
This commit is contained in:
riastradh 2023-05-09 12:49:00 +00:00
parent 76abd28dc3
commit b3e71c1908
1 changed files with 2 additions and 38 deletions
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40
sys/dev/dkwedge/dk.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: dk.c,v 1.154 2023/05/09 12:04:04 riastradh Exp $ */
/* $NetBSD: dk.c,v 1.155 2023/05/09 12:49:00 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 1.154 2023/05/09 12:04:04 riastradh Exp $");
__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.155 2023/05/09 12:49:00 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_dkwedge.h"
@ -91,8 +91,6 @@ struct dkwedge_softc {
struct callout sc_restart_ch; /* callout to restart I/O */
kmutex_t sc_iolock;
kcondvar_t sc_dkdrn;
u_int sc_iopend; /* I/Os pending */
bool sc_iostop; /* don't schedule restart */
int sc_mode; /* parent open mode */
};
@ -197,21 +195,6 @@ dkwedge_attach(device_t parent, device_t self, void *aux)
aprint_error_dev(self, "couldn't establish power handler\n");
}
/*
* dkwedge_wait_drain:
*
* Wait for I/O on the wedge to drain.
*/
static void
dkwedge_wait_drain(struct dkwedge_softc *sc)
{
mutex_enter(&sc->sc_iolock);
while (sc->sc_iopend != 0)
cv_wait(&sc->sc_dkdrn, &sc->sc_iolock);
mutex_exit(&sc->sc_iolock);
}
/*
* dkwedge_compute_pdev:
*
@ -441,7 +424,6 @@ dkwedge_add(struct dkwedge_info *dkw)
callout_setfunc(&sc->sc_restart_ch, dkrestart, sc);
mutex_init(&sc->sc_iolock, MUTEX_DEFAULT, IPL_BIO);
cv_init(&sc->sc_dkdrn, "dkdrn");
/*
* Wedge will be added; increment the wedge count for the parent.
@ -484,7 +466,6 @@ dkwedge_add(struct dkwedge_info *dkw)
}
mutex_exit(&pdk->dk_openlock);
if (error) {
cv_destroy(&sc->sc_dkdrn);
mutex_destroy(&sc->sc_iolock);
bufq_free(sc->sc_bufq);
dkwedge_size_fini(sc);
@ -542,7 +523,6 @@ dkwedge_add(struct dkwedge_info *dkw)
LIST_REMOVE(sc, sc_plink);
mutex_exit(&pdk->dk_openlock);
cv_destroy(&sc->sc_dkdrn);
mutex_destroy(&sc->sc_iolock);
bufq_free(sc->sc_bufq);
dkwedge_size_fini(sc);
@ -572,7 +552,6 @@ dkwedge_add(struct dkwedge_info *dkw)
LIST_REMOVE(sc, sc_plink);
mutex_exit(&pdk->dk_openlock);
cv_destroy(&sc->sc_dkdrn);
mutex_destroy(&sc->sc_iolock);
bufq_free(sc->sc_bufq);
dkwedge_size_fini(sc);
@ -710,14 +689,6 @@ dkwedge_detach(device_t self, int flags)
mutex_exit(&sc->sc_iolock);
callout_halt(&sc->sc_restart_ch, NULL);
/*
* dkstart() will kill any queued buffers now that the
* state of the wedge is not RUNNING. Once we've done
* that, wait for any other pending I/O to complete.
*/
dkstart(sc);
dkwedge_wait_drain(sc);
/* Locate the wedge major numbers. */
bmaj = bdevsw_lookup_major(&dk_bdevsw);
cmaj = cdevsw_lookup_major(&dk_cdevsw);
@ -763,7 +734,6 @@ dkwedge_detach(device_t self, int flags)
rw_exit(&dkwedges_lock);
mutex_destroy(&sc->sc_iolock);
cv_destroy(&sc->sc_dkdrn);
dkwedge_size_fini(sc);
free(sc, M_DKWEDGE);
@ -1484,7 +1454,6 @@ dkstrategy(struct buf *bp)
/* Place it in the queue and start I/O on the unit. */
mutex_enter(&sc->sc_iolock);
sc->sc_iopend++;
disk_wait(&sc->sc_dk);
bufq_put(sc->sc_bufq, bp);
mutex_exit(&sc->sc_iolock);
@ -1514,8 +1483,6 @@ dkstart(struct dkwedge_softc *sc)
while ((bp = bufq_peek(sc->sc_bufq)) != NULL) {
if (sc->sc_iostop) {
(void) bufq_get(sc->sc_bufq);
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;
@ -1601,9 +1568,6 @@ dkiodone(struct buf *bp)
putiobuf(bp);
mutex_enter(&sc->sc_iolock);
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);
mutex_exit(&sc->sc_iolock);