Author: mav
Date: Thu Dec 5 04:03:08 2019
New Revision: 355410
URL: https://svnweb.freebsd.org/changeset/base/355410
Log:
Switch GEOM_DEV from make_dev_p() to make_dev_s().
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.
Modified:
head/sys/geom/geom_dev.c
Modified: head/sys/geom/geom_dev.c
==============================================================================
--- head/sys/geom/geom_dev.c Thu Dec 5 02:01:47 2019 (r355409)
+++ head/sys/geom/geom_dev.c Thu Dec 5 04:03:08 2019 (r355410)
@@ -334,6 +334,7 @@ g_dev_taste(struct g_class *mp, struct g_provider *pp,
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,
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,
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, struc
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, struc
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, stru
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, stru
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);
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