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transferlockers() is a very dangerous and hack-ish function as waiters

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should never be moved by one lock to another.
As, luckily, nothing in our tree is using it, axe the function.

This breaks lockmgr KPI, so interested, third-party modules should update
their source code with appropriate replacement.

Ok'ed by: ups, rwatson
MFC after: 3 days
This commit is contained in:
Attilio Rao 2007-11-24 04:22:28 +00:00
parent 1a94fde847
commit 2c2bebfcb3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=173876
2 changed files with 0 additions and 29 deletions
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28
sys/kern/kern_lock.c
View File

@ -505,34 +505,6 @@ acquiredrain(struct lock *lkp, int extflags) {
return 0;
}
/*
* Transfer any waiting processes from one lock to another.
*/
void
transferlockers(from, to)
struct lock *from;
struct lock *to;
{
KASSERT(from != to, ("lock transfer to self"));
KASSERT((from->lk_flags&LK_WAITDRAIN) == 0, ("transfer draining lock"));
mtx_lock(from->lk_interlock);
if (from->lk_waitcount == 0) {
mtx_unlock(from->lk_interlock);
return;
}
from->lk_newlock = to;
wakeup((void *)from);
msleep(&from->lk_newlock, from->lk_interlock, from->lk_prio,
"lkxfer", 0);
from->lk_newlock = NULL;
from->lk_flags &= ~(LK_WANT_EXCL | LK_WANT_UPGRADE);
KASSERT(from->lk_waitcount == 0, ("active lock"));
mtx_unlock(from->lk_interlock);
}
/*
* Initialize a lock; required before use.
*/

1
sys/sys/lockmgr.h
View File

@ -204,7 +204,6 @@ void lockdestroy(struct lock *);
int _lockmgr(struct lock *, u_int flags,
struct mtx *, struct thread *p, char *file, int line);
void transferlockers(struct lock *, struct lock *);
void lockmgr_printinfo(struct lock *);
int lockstatus(struct lock *, struct thread *);
int lockcount(struct lock *);