/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* Copyright (c) 1991, 1993
* The Regents of the University of California.
* Copyright (c) 1990 University of Utah.
*
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vnode_pager.c 8.8 (Berkeley) 2/13/94
* from: Id: uvm_vnode.c,v 1.1.2.26 1998/02/02 20:38:07 chuck Exp
*/
/*
* uvn_reference
*
* duplicate a reference to a VM object. Note that the reference
* count must already be at least one (the passed in reference) so
* there is no chance of the uvn being killed or locked out here.
*
* => caller must call with object unlocked.
* => caller must be using the same accessprot as was used at attach time
*/
/*
* uvn_put: flush page data to backing store.
*
* => object must be locked on entry! VOP_PUTPAGES must unlock it.
* => flags: PGO_SYNCIO -- use sync. I/O
*/
static int
uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags)
{
struct vnode *vp = (struct vnode *)uobj;
int error;
/*
* uvn_get: get pages (synchronously) from backing store
*
* => prefer map unlocked (not required)
* => object must be locked! we will _unlock_ it before starting any I/O.
* => flags: PGO_LOCKED: fault data structures are locked
* => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx]
* => NOTE: caller must check for released pages!!
*/
static int
uvn_get(struct uvm_object *uobj, voff_t offset,
struct vm_page **pps /* IN/OUT */,
int *npagesp /* IN (OUT if PGO_LOCKED)*/,
int centeridx, vm_prot_t access_type, int advice, int flags)
{
struct vnode *vp = (struct vnode *)uobj;
int error;
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(ubchist, "vp %#jx off %#jx", (uintptr_t)vp, offset,
0, 0);
/*
* uvn_findpages:
* return the page for the uobj and offset requested, allocating if needed.
* => uobj must be locked.
* => returned pages will be BUSY.
*/
int
uvn_findpages(struct uvm_object *uobj, voff_t offset, unsigned int *npagesp,
struct vm_page **pgs, struct uvm_page_array *a, unsigned int flags)
{
unsigned int count, found, npages;
int i, rv;
struct uvm_page_array a_store;
if (a == NULL) {
/*
* XXX fragile API
* note that the array can be the one supplied by the caller of
* uvn_findpages. in that case, fillflags used by the caller
* might not match strictly with ours.
* in particular, the caller might have filled the array
* without DENSE but passed us UFP_DIRTYONLY (thus DENSE).
*/
const unsigned int fillflags =
((flags & UFP_BACKWARD) ? UVM_PAGE_ARRAY_FILL_BACKWARD : 0) |
((flags & UFP_DIRTYONLY) ?
(UVM_PAGE_ARRAY_FILL_DIRTY|UVM_PAGE_ARRAY_FILL_DENSE) : 0);
a = &a_store;
uvm_page_array_init(a, uobj, fillflags);
}
count = found = 0;
npages = *npagesp;
if (flags & UFP_BACKWARD) {
for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) {
rv = uvn_findpage(uobj, offset, &pgs[i], flags, a,
i + 1);
if (rv == 0) {
if (flags & UFP_DIRTYONLY)
break;
} else
found++;
count++;
}
} else {
for (i = 0; i < npages; i++, offset += PAGE_SIZE) {
rv = uvn_findpage(uobj, offset, &pgs[i], flags, a,
npages - i);
if (rv == 0) {
if (flags & UFP_DIRTYONLY)
break;
} else
found++;
count++;
}
}
if (a == &a_store) {
uvm_page_array_fini(a);
}
*npagesp = count;
return (found);
}
/*
* uvn_findpage: find a single page
*
* if a suitable page was found, put it in *pgp and return 1.
* otherwise return 0.
*/
static int
uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp,
unsigned int flags, struct uvm_page_array *a, unsigned int nleft)
{
struct vm_page *pg;
UVMHIST_FUNC(__func__);
UVMHIST_CALLARGS(ubchist, "vp %#jx off %#jx", (uintptr_t)uobj, offset,
0, 0);
/*
* NOBUSY must come with NOWAIT and NOALLOC. if NOBUSY is
* specified, this may be called with a reader lock.
*/
/* nope? allocate one now */
if (pg == NULL) {
if (flags & UFP_NOALLOC) {
UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0);
return 0;
}
pg = uvm_pagealloc(uobj, offset, NULL,
UVM_FLAG_COLORMATCH);
if (pg == NULL) {
if (flags & UFP_NOWAIT) {
UVMHIST_LOG(ubchist, "nowait",0,0,0,0);
return 0;
}
rw_exit(uobj->vmobjlock);
uvm_wait("uvnfp1");
uvm_page_array_clear(a);
rw_enter(uobj->vmobjlock, RW_WRITER);
continue;
}
UVMHIST_LOG(ubchist, "alloced %#jx (color %ju)",
(uintptr_t)pg, VM_PGCOLOR(pg), 0, 0);
KASSERTMSG(uvm_pagegetdirty(pg) ==
UVM_PAGE_STATUS_CLEAN, "page %p not clean", pg);
break;
} else if (flags & UFP_NOCACHE) {
UVMHIST_LOG(ubchist, "nocache",0,0,0,0);
goto skip;
}
/* page is there, see if we need to wait on it */
if ((pg->flags & PG_BUSY) != 0) {
if (flags & UFP_NOWAIT) {
UVMHIST_LOG(ubchist, "nowait",0,0,0,0);
goto skip;
}
UVMHIST_LOG(ubchist, "wait %#jx (color %ju)",
(uintptr_t)pg, VM_PGCOLOR(pg), 0, 0);
uvm_pagewait(pg, uobj->vmobjlock, "uvnfp2");
uvm_page_array_clear(a);
rw_enter(uobj->vmobjlock, RW_WRITER);
continue;
}
/*
* uvm_vnp_setsize: grow or shrink a vnode uobj
*
* grow => just update size value
* shrink => toss un-needed pages
*
* => we assume that the caller has a reference of some sort to the
* vnode in question so that it will not be yanked out from under
* us.
*/
rw_enter(uobj->vmobjlock, RW_WRITER);
UVMHIST_LOG(ubchist, "vp %#jx old %#jx new %#jx",
(uintptr_t)vp, vp->v_size, newsize, 0);
/*
* now check if the size has changed: if we shrink we had better
* toss some pages...
*/
KASSERT(newsize != VSIZENOTSET);
KASSERT(newsize >= 0);
KASSERTMSG(vp->v_size <= vp->v_writesize, "vp=%p"
" v_size=0x%llx v_writesize=0x%llx", vp,
(unsigned long long)vp->v_size,
(unsigned long long)vp->v_writesize);
KASSERTMSG((vp->v_size == vp->v_writesize ||
newsize == vp->v_writesize || newsize <= vp->v_size),
"vp=%p v_size=0x%llx v_writesize=0x%llx newsize=0x%llx",
vp,
(unsigned long long)vp->v_size,
(unsigned long long)vp->v_writesize,
(unsigned long long)newsize);
oldsize = vp->v_writesize;
/*
* check whether size shrinks
* if old size hasn't been set, there are no pages to drop
* if there was an integer overflow in pgend, then this is no shrink
*/
if (oldsize > pgend && oldsize != VSIZENOTSET && pgend >= 0) {
(void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO);
rw_enter(uobj->vmobjlock, RW_WRITER);
}
mutex_enter(vp->v_interlock);
vp->v_size = vp->v_writesize = newsize;
mutex_exit(vp->v_interlock);
rw_exit(uobj->vmobjlock);
}
/*
* v_interlock is not held here, but VI_EXECMAP is only ever changed
* with the vmobjlock held too.
*/
iflag = atomic_load_relaxed(&vp->v_iflag);
return (iflag & VI_EXECMAP) != 0;
}
