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Acquire read lock on the src object for vm_fault_copy_entry().

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Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc
This commit is contained in:
Attilio Rao 2013-05-22 15:11:00 +00:00
parent 8d8a4892fe
commit 83b375ea16
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=250909
1 changed files with 4 additions and 4 deletions
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8
sys/vm/vm_fault.c
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@ -1318,7 +1318,7 @@ vm_fault_copy_entry(vm_map_t dst_map, vm_map_t src_map,
* (Because the source is wired down, the page will be in
* memory.)
*/
VM_OBJECT_WLOCK(src_object);
VM_OBJECT_RLOCK(src_object);
object = src_object;
pindex = src_pindex + dst_pindex;
while ((src_m = vm_page_lookup(object, pindex)) == NULL &&
@ -1327,15 +1327,15 @@ vm_fault_copy_entry(vm_map_t dst_map, vm_map_t src_map,
/*
* Allow fallback to backing objects if we are reading.
*/
VM_OBJECT_WLOCK(backing_object);
VM_OBJECT_RLOCK(backing_object);
pindex += OFF_TO_IDX(object->backing_object_offset);
VM_OBJECT_WUNLOCK(object);
VM_OBJECT_RUNLOCK(object);
object = backing_object;
}
if (src_m == NULL)
panic("vm_fault_copy_wired: page missing");
pmap_copy_page(src_m, dst_m);
VM_OBJECT_WUNLOCK(object);
VM_OBJECT_RUNLOCK(object);
dst_m->valid = VM_PAGE_BITS_ALL;
dst_m->dirty = VM_PAGE_BITS_ALL;
VM_OBJECT_WUNLOCK(dst_object);