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Fix a list corruption issue in cloning device management using the

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western strategy ("allocate first, ask questions later") so we can
extend the devmtx coverage to the clone list.
This commit is contained in:
Poul-Henning Kamp 2005-01-24 12:44:56 +00:00
parent d34dd851b8
commit 027b1f716c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=140733
1 changed files with 41 additions and 16 deletions
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57
sys/kern/kern_conf.c
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@ -60,7 +60,7 @@ static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
static struct mtx devmtx;
static void freedev(struct cdev *dev);
static struct cdev *newdev(int x, int y);
static struct cdev *newdev(int x, int y, struct cdev *);
void
dev_lock(void)
@ -286,21 +286,23 @@ allocdev(void)
}
static struct cdev *
newdev(int x, int y)
newdev(int x, int y, struct cdev *si)
{
struct cdev *si;
struct cdev *si2;
dev_t udev;
int hash;
mtx_assert(&devmtx, MA_OWNED);
if (x == umajor(NODEV) && y == uminor(NODEV))
panic("newdev of NODEV");
udev = (x << 8) | y;
hash = udev % DEVT_HASH;
LIST_FOREACH(si, &dev_hash[hash], si_hash) {
if (si->si_udev == udev)
return (si);
LIST_FOREACH(si2, &dev_hash[hash], si_hash) {
if (si2->si_udev == udev) {
freedev(si);
return (si2);
}
}
si = allocdev();
si->si_udev = udev;
LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
return (si);
@ -327,14 +329,17 @@ findcdev(dev_t udev)
struct cdev *si;
int hash;
mtx_assert(&devmtx, MA_NOTOWNED);
if (udev == NODEV)
return (NULL);
dev_lock();
hash = udev % DEVT_HASH;
LIST_FOREACH(si, &dev_hash[hash], si_hash) {
if (si->si_udev == udev)
return (si);
break;
}
return (NULL);
dev_unlock();
return (si);
}
int
@ -449,7 +454,9 @@ make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, con
if (!(devsw->d_flags & D_INIT))
prep_cdevsw(devsw);
dev = newdev(devsw->d_maj, minornr);
dev = allocdev();
dev_lock();
dev = newdev(devsw->d_maj, minornr, dev);
if (dev->si_flags & SI_CHEAPCLONE &&
dev->si_flags & SI_NAMED &&
dev->si_devsw == devsw) {
@ -458,9 +465,9 @@ make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, con
* simplifies cloning devices.
* XXX: still ??
*/
dev_unlock();
return (dev);
}
dev_lock();
KASSERT(!(dev->si_flags & SI_NAMED),
("make_dev() by driver %s on pre-existing device (maj=%d, min=%d, name=%s)",
devsw->d_name, major(dev), minor(dev), devtoname(dev)));
@ -693,7 +700,7 @@ int
clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra)
{
struct clonedevs *cd;
struct cdev *dev, *dl, *de;
struct cdev *dev, *ndev, *dl, *de;
int unit, low, u;
KASSERT(*cdp != NULL,
@ -715,13 +722,19 @@ clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **
* the end of the list.
*/
unit = *up;
ndev = allocdev();
dev_lock();
low = extra;
de = dl = NULL;
cd = *cdp;
LIST_FOREACH(dev, &cd->head, si_clone) {
KASSERT(dev->si_flags & SI_CLONELIST,
("Dev %p(%s) should be on clonelist", dev, dev->si_name));
u = dev2unit(dev);
if (u == (unit | extra)) {
*dp = dev;
freedev(ndev);
dev_unlock();
return (0);
}
if (unit == -1 && u == low) {
@ -733,13 +746,20 @@ clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **
dl = dev;
break;
}
de = dev;
}
if (unit == -1)
unit = low & CLONE_UNITMASK;
dev = newdev(csw->d_maj, unit2minor(unit | extra));
dev = newdev(csw->d_maj, unit2minor(unit | extra), ndev);
if (dev->si_flags & SI_CLONELIST) {
printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
printf("unit=%d\n", unit);
LIST_FOREACH(dev, &cd->head, si_clone) {
printf("\t%p %s\n", dev, dev->si_name);
}
panic("foo");
}
KASSERT(!(dev->si_flags & SI_CLONELIST),
("Dev %p should not be on clonelist", dev));
("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
if (dl != NULL)
LIST_INSERT_BEFORE(dl, dev, si_clone);
else if (de != NULL)
@ -748,6 +768,7 @@ clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **
LIST_INSERT_HEAD(&cd->head, dev, si_clone);
dev->si_flags |= SI_CLONELIST;
*up = unit;
dev_unlock();
return (1);
}
@ -764,11 +785,15 @@ clone_cleanup(struct clonedevs **cdp)
cd = *cdp;
if (cd == NULL)
return;
dev_lock();
LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
KASSERT(dev->si_flags & SI_CLONELIST,
("Dev %p(%s) should be on clonelist", dev, dev->si_name));
KASSERT(dev->si_flags & SI_NAMED,
("Driver has goofed in cloning underways udev %x", dev->si_udev));
destroy_dev(dev);
idestroy_dev(dev);
}
dev_unlock();
free(cd, M_DEVBUF);
*cdp = NULL;
}