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- Add md_mtx lock to protect ID number and list of devices.

Browse Source 
- Always check mdnew() return value, as even in !autounit case
  kthread_create() can fail.

Those two changes fix serval panics provked by simple stress test.

Tested by:	Kris The BugMagnet
MFC after:	3 days
This commit is contained in:
Pawel Jakub Dawidek 2005-08-31 19:45:11 +00:00
parent 122562cd2b
commit 7ee3c044d0
1 changed files with 37 additions and 25 deletions
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62
sys/dev/md/md.c
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@ -112,6 +112,8 @@ static g_access_t g_md_access;
static int mdunits;
static struct cdev *status_dev = 0;
static struct mtx md_mtx;
MTX_SYSINIT(md_mtx, &md_mtx, "md", MTX_DEF);
static d_ioctl_t mdctlioctl;
@ -708,44 +710,54 @@ mdfind(int unit)
{
struct md_s *sc;
/* XXX: LOCK(unique unit numbers) */
mtx_lock(&md_mtx);
LIST_FOREACH(sc, &md_softc_list, list) {
if (sc->unit == unit)
break;
}
/* XXX: UNLOCK(unique unit numbers) */
mtx_unlock(&md_mtx);
return (sc);
}
static struct md_s *
mdnew(int unit)
mdnew(int unit, int *errp)
{
struct md_s *sc;
struct md_s *sc, *sc2;
int error, max = -1;
/* XXX: LOCK(unique unit numbers) */
LIST_FOREACH(sc, &md_softc_list, list) {
if (sc->unit == unit) {
/* XXX: UNLOCK(unique unit numbers) */
sc = (struct md_s *)malloc(sizeof *sc, M_MD, M_WAITOK | M_ZERO);
bioq_init(&sc->bio_queue);
mtx_init(&sc->queue_mtx, "md bio queue", NULL, MTX_DEF);
mtx_lock(&md_mtx);
LIST_FOREACH(sc2, &md_softc_list, list) {
if (sc2->unit == unit) {
mtx_unlock(&md_mtx);
mtx_destroy(&sc->queue_mtx);
free(sc, M_MD);
if (errp != NULL)
*errp = EBUSY;
return (NULL);
}
if (sc->unit > max)
max = sc->unit;
if (sc2->unit > max)
max = sc2->unit;
}
if (unit == -1)
unit = max + 1;
sc = (struct md_s *)malloc(sizeof *sc, M_MD, M_WAITOK | M_ZERO);
sc->unit = unit;
bioq_init(&sc->bio_queue);
mtx_init(&sc->queue_mtx, "md bio queue", NULL, MTX_DEF);
sprintf(sc->name, "md%d", unit);
LIST_INSERT_HEAD(&md_softc_list, sc, list);
mtx_unlock(&md_mtx);
error = kthread_create(md_kthread, sc, &sc->procp, 0, 0,"%s", sc->name);
if (error != 0) {
mtx_lock(&md_mtx);
LIST_REMOVE(sc, list);
mtx_unlock(&md_mtx);
mtx_destroy(&sc->queue_mtx);
free(sc, M_MD);
if (errp != NULL)
*errp = error;
return (NULL);
}
LIST_INSERT_HEAD(&md_softc_list, sc, list);
/* XXX: UNLOCK(unique unit numbers) */
return (sc);
}
@ -955,9 +967,9 @@ mddestroy(struct md_s *sc, struct thread *td)
if (sc->uma)
uma_zdestroy(sc->uma);
/* XXX: LOCK(unique unit numbers) */
mtx_lock(&md_mtx);
LIST_REMOVE(sc, list);
/* XXX: UNLOCK(unique unit numbers) */
mtx_unlock(&md_mtx);
free(sc, M_MD);
return (0);
}
@ -1061,14 +1073,14 @@ mdctlioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread
default:
return (EINVAL);
}
if (mdio->md_options & MD_AUTOUNIT) {
sc = mdnew(-1);
if (mdio->md_options & MD_AUTOUNIT)
sc = mdnew(-1, &error);
else
sc = mdnew(mdio->md_unit, &error);
if (sc == NULL)
return (error);
if (mdio->md_options & MD_AUTOUNIT)
mdio->md_unit = sc->unit;
} else {
sc = mdnew(mdio->md_unit);
if (sc == NULL)
return (EBUSY);
}
sc->type = mdio->md_type;
sc->mediasize = mdio->md_mediasize;
if (mdio->md_sectorsize == 0)
@ -1142,7 +1154,7 @@ md_preloaded(u_char *image, size_t length)
{
struct md_s *sc;
sc = mdnew(-1);
sc = mdnew(-1, NULL);
if (sc == NULL)
return;
sc->type = MD_PRELOAD;