1e84067639
- Fix an old bug of possible lock against oneself (uao_detach_locked() is called from uao_swap_off() with uao_list_lock acquired). Also removes the try-lock dance in uao_swap_off(), since the lock order changes.
120 lines
4.5 KiB
C
120 lines
4.5 KiB
C
/* $NetBSD: uvm_object.h,v 1.33 2012/09/14 22:20:50 rmind Exp $ */
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/*
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* Copyright (c) 1997 Charles D. Cranor and Washington University.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp
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*/
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#ifndef _UVM_UVM_OBJECT_H_
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#define _UVM_UVM_OBJECT_H_
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#include <sys/queue.h>
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#include <sys/rbtree.h>
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#include <uvm/uvm_pglist.h>
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/*
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* The UVM memory object interface. Notes:
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*
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* A UVM memory object represents a list of pages, which are managed by
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* the object's pager operations (uvm_object::pgops). All pages belonging
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* to an object are owned by it and thus protected by the object lock.
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*
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* The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects.
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* By default, the lock is allocated dynamically using mutex_obj(9) cache.
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* Lock sharing is normally used when there is an underlying object. For
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* example, vnode representing a file may have an underlying node, which
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* is the case for tmpfs and layered file systems. In such case, vnode's
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* UVM object and the underlying UVM object shares the lock (note that the
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* vnode_t::v_interlock points to uvm_object::vmobjlock).
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*
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* The reference count is managed atomically for the anonymous UVM objects.
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* For other objects, it is arbitrary (may use the lock or atomics).
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*/
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struct uvm_object {
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kmutex_t * vmobjlock; /* lock on memq */
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const struct uvm_pagerops *pgops; /* pager ops */
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struct pglist memq; /* pages in this object */
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int uo_npages; /* # of pages in memq */
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unsigned uo_refs; /* reference count */
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struct rb_tree rb_tree; /* tree of pages */
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LIST_HEAD(,ubc_map) uo_ubc; /* ubc mappings */
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};
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/*
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* UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the
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* object is a kernel memory object rather than a normal one (kernel
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* memory objects don't have reference counts -- they never die).
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*
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* this value is used to detected kernel object mappings at uvm_unmap()
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* time. normally when an object is unmapped its pages eventaully become
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* deactivated and then paged out and/or freed. this is not useful
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* for kernel objects... when a kernel object is unmapped we always want
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* to free the resources associated with the mapping. UVM_OBJ_KERN
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* allows us to decide which type of unmapping we want to do.
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*/
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#define UVM_OBJ_KERN (-2)
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#define UVM_OBJ_IS_KERN_OBJECT(uobj) \
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((uobj)->uo_refs == UVM_OBJ_KERN)
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#ifdef _KERNEL
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extern const struct uvm_pagerops uvm_vnodeops;
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extern const struct uvm_pagerops uvm_deviceops;
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extern const struct uvm_pagerops ubc_pager;
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extern const struct uvm_pagerops aobj_pager;
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#define UVM_OBJ_IS_VNODE(uobj) \
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((uobj)->pgops == &uvm_vnodeops)
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#define UVM_OBJ_IS_DEVICE(uobj) \
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((uobj)->pgops == &uvm_deviceops)
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#define UVM_OBJ_IS_VTEXT(uobj) \
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(UVM_OBJ_IS_VNODE(uobj) && uvn_text_p(uobj))
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#define UVM_OBJ_IS_CLEAN(uobj) \
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(UVM_OBJ_IS_VNODE(uobj) && uvn_clean_p(uobj))
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/*
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* UVM_OBJ_NEEDS_WRITEFAULT: true if the uobj needs to detect modification.
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* (ie. wants to avoid writable user mappings.)
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*
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* XXX bad name
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*/
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#define UVM_OBJ_NEEDS_WRITEFAULT(uobj) \
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(UVM_OBJ_IS_VNODE(uobj) && uvn_needs_writefault_p(uobj))
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#define UVM_OBJ_IS_AOBJ(uobj) \
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((uobj)->pgops == &aobj_pager)
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extern const rb_tree_ops_t uvm_page_tree_ops;
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#endif /* _KERNEL */
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#endif /* _UVM_UVM_OBJECT_H_ */
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