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Lock the new map in vmspace_fork(). The newly allocated map should not

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be accessible outside vmspace_fork() yet, but locking it would satisfy
the protocol of the vm_map_entry_link() and other functions called
from vmspace_fork().

Use trylock that is supposedly cannot fail, to silence WITNESS warning
of the nested acquisition of the sx lock with the same name.

Suggested and reviewed by:	tegge
This commit is contained in:
kib 2009-02-08 19:55:03 +00:00
parent 0125db5772
commit 2d39ccdd94
1 changed files with 5 additions and 0 deletions
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5
sys/vm/vm_map.c
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@ -2679,6 +2679,7 @@ vmspace_fork(struct vmspace *vm1)
vm_map_entry_t old_entry;
vm_map_entry_t new_entry;
vm_object_t object;
int locked;
vm_map_lock(old_map);
@ -2689,6 +2690,8 @@ vmspace_fork(struct vmspace *vm1)
vm2->vm_daddr = vm1->vm_daddr;
vm2->vm_maxsaddr = vm1->vm_maxsaddr;
new_map = &vm2->vm_map; /* XXX */
locked = vm_map_trylock(new_map); /* trylock to silence WITNESS */
KASSERT(locked, ("vmspace_fork: lock failed"));
new_map->timestamp = 1;
old_entry = old_map->header.next;
@ -2780,6 +2783,8 @@ vmspace_fork(struct vmspace *vm1)
}
unlock_and_return:
vm_map_unlock(old_map);
if (vm2 != NULL)
vm_map_unlock(new_map);
return (vm2);
}