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devfs_free() calls free_unr(), that may sleep.

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Postpone call to devfs_free() after cdev mutex is dropped. Reuse
cdp_list link for queuing devices awaiting deletion in the
cdevp_free_list.

Reported by:	Hans Petter Selasky <hselasky c2i net>
Tested by:	Peter Holm
Approved by:	re (kensmith)
MFC after:	2 weeks
This commit is contained in:
Konstantin Belousov 2007-06-19 13:19:23 +00:00
parent 7550e3eac4
commit 9bc911d4a2
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=170950
1 changed files with 34 additions and 6 deletions
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40
sys/kern/kern_conf.c
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@ -54,6 +54,9 @@ static struct cdev *make_dev_credv(struct cdevsw *devsw, int minornr,
struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
va_list ap);
static struct cdev_priv_list cdevp_free_list =
TAILQ_HEAD_INITIALIZER(cdevp_free_list);
void
dev_lock(void)
{
@ -61,6 +64,31 @@ dev_lock(void)
mtx_lock(&devmtx);
}
static void
dev_unlock_and_free(void)
{
struct cdev_priv *cdp;
mtx_assert(&devmtx, MA_OWNED);
while ((cdp = TAILQ_FIRST(&cdevp_free_list)) != NULL) {
TAILQ_REMOVE(&cdevp_free_list, cdp, cdp_list);
mtx_unlock(&devmtx);
devfs_free(&cdp->cdp_c);
mtx_lock(&devmtx);
}
mtx_unlock(&devmtx);
}
static void
dev_free_devlocked(struct cdev *cdev)
{
struct cdev_priv *cdp;
mtx_assert(&devmtx, MA_OWNED);
cdp = cdev->si_priv;
TAILQ_INSERT_HEAD(&cdevp_free_list, cdp, cdp_list);
}
void
dev_unlock(void)
{
@ -417,7 +445,7 @@ newdev(struct cdevsw *csw, int y, struct cdev *si)
udev = y;
LIST_FOREACH(si2, &csw->d_devs, si_list) {
if (si2->si_drv0 == udev) {
devfs_free(si);
dev_free_devlocked(si);
return (si2);
}
}
@ -548,7 +576,7 @@ make_dev_credv(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid,
* simplifies cloning devices.
* XXX: still ??
*/
dev_unlock();
dev_unlock_and_free();
return (dev);
}
KASSERT(!(dev->si_flags & SI_NAMED),
@ -709,7 +737,7 @@ destroy_devl(struct cdev *dev)
if (dev->si_refcount > 0) {
LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
} else {
devfs_free(dev);
dev_free_devlocked(dev);
}
}
@ -719,7 +747,7 @@ destroy_dev(struct cdev *dev)
dev_lock();
destroy_devl(dev);
dev_unlock();
dev_unlock_and_free();
}
const char *
@ -839,8 +867,8 @@ clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **
u = dev2unit(dev);
if (u == (unit | extra)) {
*dp = dev;
devfs_free(ndev);
dev_unlock();
devfs_free(ndev);
return (0);
}
if (unit == -1 && u == low) {
@ -876,7 +904,7 @@ 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();
dev_unlock_and_free();
return (1);
}