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Remove brain damaged code in witness_lock(). We could have easily

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just used PCPU_GET(spinlocks) w/o needing the w_mtx held.  It is more
correct to just check td_critnest now though.
This commit is contained in:
John Baldwin 2002-01-05 08:29:54 +00:00
parent e0c58e64c0
commit 422f61655f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=88899
1 changed files with 3 additions and 16 deletions
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19
sys/kern/subr_witness.c
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@ -475,26 +475,13 @@ witness_lock(struct lock_object *lock, int flags, const char *file, int line)
class = lock->lo_class;
td = curthread;
/*
* We have to hold a spinlock to keep lock_list valid across the check
* in the LC_SLEEPLOCK case. In the LC_SPINLOCK case, it is already
* protected by the spinlock we are currently performing the witness
* checks on, so it is ok to release the lock after performing this
* check. All we have to protect is the LC_SLEEPLOCK case when no
* spinlocks are held as we may get preempted during this check and
* lock_list could end up pointing to some other CPU's spinlock list.
*/
mtx_lock_spin(&w_mtx);
lock_list = PCPU_PTR(spinlocks);
if (class->lc_flags & LC_SLEEPLOCK) {
if (*lock_list != NULL && (flags & LOP_TRYLOCK) == 0) {
mtx_unlock_spin(&w_mtx);
if (td->td_critnest != 0 && (flags & LOP_TRYLOCK) == 0)
panic("blockable sleep lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
}
lock_list = &td->td_sleeplocks;
}
mtx_unlock_spin(&w_mtx);
} else
lock_list = PCPU_PTR(spinlocks);
/*
* Try locks do not block if they fail to acquire the lock, thus