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Switch GEOM_DEV from make_dev_p() to make_dev_s().

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It closes the race condition and so allows to remove few NULL checks.

Also while there, use dev->si_drv1 in addition to cp->private to store
softc pointer.  For calls coming from the dev side it gives reliable cache
hit instead of often miss before.

MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.
This commit is contained in:
Alexander Motin 2019-12-05 04:03:08 +00:00
parent 2b289d0bff
commit e61ed7983e
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=355410
1 changed files with 16 additions and 12 deletions
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28
sys/geom/geom_dev.c
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@ -334,6 +334,7 @@ g_dev_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
int error;
struct cdev *dev, *adev;
char buf[SPECNAMELEN + 6];
struct make_dev_args args;
g_trace(G_T_TOPOLOGY, "dev_taste(%s,%s)", mp->name, pp->name);
g_topology_assert();
@ -346,8 +347,17 @@ g_dev_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
error = g_attach(cp, pp);
KASSERT(error == 0,
("g_dev_taste(%s) failed to g_attach, err=%d", pp->name, error));
error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &dev,
&g_dev_cdevsw, NULL, UID_ROOT, GID_OPERATOR, 0640, "%s", gp->name);
make_dev_args_init(&args);
args.mda_flags = MAKEDEV_CHECKNAME | MAKEDEV_WAITOK;
args.mda_devsw = &g_dev_cdevsw;
args.mda_cr = NULL;
args.mda_uid = UID_ROOT;
args.mda_gid = GID_OPERATOR;
args.mda_mode = 0640;
args.mda_si_drv1 = sc;
args.mda_si_drv2 = cp;
error = make_dev_s(&args, &sc->sc_dev, "%s", gp->name);
if (error != 0) {
printf("%s: make_dev_p() failed (gp->name=%s, error=%d)\n",
__func__, gp->name, error);
@ -358,11 +368,9 @@ g_dev_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
g_free(sc);
return (NULL);
}
dev = sc->sc_dev;
dev->si_flags |= SI_UNMAPPED;
sc->sc_dev = dev;
dev->si_iosize_max = MAXPHYS;
dev->si_drv2 = cp;
error = init_dumpdev(dev);
if (error != 0)
printf("%s: init_dumpdev() failed (gp->name=%s, error=%d)\n",
@ -397,8 +405,6 @@ g_dev_open(struct cdev *dev, int flags, int fmt, struct thread *td)
int error, r, w, e;
cp = dev->si_drv2;
if (cp == NULL)
return (ENXIO); /* g_dev_taste() not done yet */
g_trace(G_T_ACCESS, "g_dev_open(%s, %d, %d, %p)",
cp->geom->name, flags, fmt, td);
@ -429,7 +435,7 @@ g_dev_open(struct cdev *dev, int flags, int fmt, struct thread *td)
error = g_access(cp, r, w, e);
g_topology_unlock();
if (error == 0) {
sc = cp->private;
sc = dev->si_drv1;
mtx_lock(&sc->sc_mtx);
if (sc->sc_open == 0 && (sc->sc_active & SC_A_ACTIVE) != 0)
wakeup(&sc->sc_active);
@ -451,8 +457,6 @@ g_dev_close(struct cdev *dev, int flags, int fmt, struct thread *td)
int error, r, w, e;
cp = dev->si_drv2;
if (cp == NULL)
return (ENXIO);
g_trace(G_T_ACCESS, "g_dev_close(%s, %d, %d, %p)",
cp->geom->name, flags, fmt, td);
@ -477,7 +481,7 @@ g_dev_close(struct cdev *dev, int flags, int fmt, struct thread *td)
if (r + w + e == 0)
return (EINVAL);
sc = cp->private;
sc = dev->si_drv1;
mtx_lock(&sc->sc_mtx);
sc->sc_open += r + w + e;
if (sc->sc_open == 0)
@ -797,7 +801,6 @@ g_dev_strategy(struct bio *bp)
("Wrong bio_cmd bio=%p cmd=%d", bp, bp->bio_cmd));
dev = bp->bio_dev;
cp = dev->si_drv2;
sc = cp->private;
KASSERT(cp->acr || cp->acw,
("Consumer with zero access count in g_dev_strategy"));
biotrack(bp, __func__);
@ -809,6 +812,7 @@ g_dev_strategy(struct bio *bp)
return;
}
#endif
sc = dev->si_drv1;
KASSERT(sc->sc_open > 0, ("Closed device in g_dev_strategy"));
atomic_add_int(&sc->sc_active, 1);