Retire clone_drain_lock

It is only ever xlocked in drain_dev_clone_events and the only consumer of
that routine does not need it -- eventhandler code already makes sure the
relevant callback is no longer running.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D36268
This commit is contained in:
Mateusz Guzik 2022-08-19 21:20:51 +00:00
parent 02d0c43c9e
commit 497240def8
6 changed files with 0 additions and 17 deletions

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@ -91,7 +91,6 @@ int devfs_pathpath(const char *, const char *);
extern struct unrhdr *devfs_inos;
extern struct mtx devmtx;
extern struct mtx devfs_de_interlock;
extern struct sx clone_drain_lock;
extern struct mtx cdevpriv_mtx;
extern TAILQ_HEAD(cdev_priv_list, cdev_priv) cdevp_list;

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@ -85,8 +85,6 @@ static MALLOC_DEFINE(M_CDEVPDATA, "DEVFSP", "Metainfo for cdev-fp data");
struct mtx devfs_de_interlock;
MTX_SYSINIT(devfs_de_interlock, &devfs_de_interlock, "devfs interlock", MTX_DEF);
struct sx clone_drain_lock;
SX_SYSINIT(clone_drain_lock, &clone_drain_lock, "clone events drain lock");
struct mtx cdevpriv_mtx;
MTX_SYSINIT(cdevpriv_mtx, &cdevpriv_mtx, "cdevpriv lock", MTX_DEF);
@ -1102,10 +1100,8 @@ devfs_lookupx(struct vop_lookup_args *ap, int *dm_unlock)
cdev = NULL;
DEVFS_DMP_HOLD(dmp);
sx_xunlock(&dmp->dm_lock);
sx_slock(&clone_drain_lock);
EVENTHANDLER_INVOKE(dev_clone,
td->td_ucred, pname, strlen(pname), &cdev);
sx_sunlock(&clone_drain_lock);
if (cdev == NULL)
sx_xlock(&dmp->dm_lock);

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@ -1523,14 +1523,6 @@ destroy_dev_drain(struct cdevsw *csw)
dev_unlock();
}
void
drain_dev_clone_events(void)
{
sx_xlock(&clone_drain_lock);
sx_xunlock(&clone_drain_lock);
}
#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>

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@ -68,9 +68,7 @@ ctty_clone(void *arg, struct ucred *cred, char *name, int namelen,
if (strcmp(name, "tty"))
return;
p = curproc;
sx_sunlock(&clone_drain_lock);
sx_slock(&proctree_lock);
sx_slock(&clone_drain_lock);
dev_lock();
if (!(p->p_flag & P_CONTROLT))
*dev = ctty;

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@ -707,7 +707,6 @@ tun_uninit(const void *unused __unused)
EVENTHANDLER_DEREGISTER(ifnet_arrival_event, arrival_tag);
EVENTHANDLER_DEREGISTER(dev_clone, clone_tag);
drain_dev_clone_events();
mtx_lock(&tunmtx);
while ((tp = TAILQ_FIRST(&tunhead)) != NULL) {

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@ -279,7 +279,6 @@ void destroy_dev(struct cdev *_dev);
int destroy_dev_sched(struct cdev *dev);
int destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg);
void destroy_dev_drain(struct cdevsw *csw);
void drain_dev_clone_events(void);
struct cdevsw *dev_refthread(struct cdev *_dev, int *_ref);
struct cdevsw *devvn_refthread(struct vnode *vp, struct cdev **devp, int *_ref);
void dev_relthread(struct cdev *_dev, int _ref);