262 lines
7 KiB
C
262 lines
7 KiB
C
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/* This file implements the methods of memory-mapped files. */
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#include <assert.h>
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#include "proto.h"
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#include "vm.h"
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#include "region.h"
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#include "glo.h"
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#include "cache.h"
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/* These functions are static so as to not pollute the
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* global namespace, and are accessed through their function
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* pointers.
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*/
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static void mappedfile_split(struct vmproc *vmp, struct vir_region *vr,
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struct vir_region *r1, struct vir_region *r2);
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static int mappedfile_unreference(struct phys_region *pr);
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static int mappedfile_pagefault(struct vmproc *vmp, struct vir_region *region,
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struct phys_region *ph, int write, vfs_callback_t callback, void *state,
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int len, int *io);
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static int mappedfile_sanitycheck(struct phys_region *pr, char *file, int line);
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static int mappedfile_writable(struct phys_region *pr);
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static int mappedfile_copy(struct vir_region *vr, struct vir_region *newvr);
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static int mappedfile_lowshrink(struct vir_region *vr, vir_bytes len);
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static void mappedfile_delete(struct vir_region *region);
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static int mappedfile_pt_flags(struct vir_region *vr);
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struct mem_type mem_type_mappedfile = {
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.name = "file-mapped memory",
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.ev_unreference = mappedfile_unreference,
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.ev_pagefault = mappedfile_pagefault,
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.ev_sanitycheck = mappedfile_sanitycheck,
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.ev_copy = mappedfile_copy,
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.writable = mappedfile_writable,
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.ev_split = mappedfile_split,
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.ev_lowshrink = mappedfile_lowshrink,
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.ev_delete = mappedfile_delete,
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.pt_flags = mappedfile_pt_flags,
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};
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static int mappedfile_pt_flags(struct vir_region *vr){
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#if defined(__arm__)
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return ARM_VM_PTE_CACHED;
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#else
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return 0;
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#endif
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}
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static int mappedfile_unreference(struct phys_region *pr)
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{
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assert(pr->ph->refcount == 0);
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if(pr->ph->phys != MAP_NONE)
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free_mem(ABS2CLICK(pr->ph->phys), 1);
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return OK;
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}
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static int cow_block(struct vmproc *vmp, struct vir_region *region,
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struct phys_region *ph, u16_t clearend)
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{
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int r;
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if((r=mem_cow(region, ph, MAP_NONE, MAP_NONE)) != OK) {
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printf("mappedfile_pagefault: COW failed\n");
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return r;
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}
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/* After COW we are a normal piece of anonymous memory. */
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ph->memtype = &mem_type_anon;
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if(clearend) {
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phys_bytes phaddr = ph->ph->phys, po = VM_PAGE_SIZE-clearend;
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assert(clearend < VM_PAGE_SIZE);
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phaddr += po;
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if(sys_memset(NONE, 0, phaddr, clearend) != OK) {
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panic("cow_block: clearend failed\n");
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}
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}
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return OK;
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}
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static int mappedfile_pagefault(struct vmproc *vmp, struct vir_region *region,
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struct phys_region *ph, int write, vfs_callback_t cb,
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void *state, int statelen, int *io)
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{
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u32_t allocflags;
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int procfd = region->param.file.fdref->fd;
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allocflags = vrallocflags(region->flags);
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assert(ph->ph->refcount > 0);
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assert(region->param.file.inited);
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assert(region->param.file.fdref);
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assert(region->param.file.fdref->dev != NO_DEV);
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/* Totally new block? Create it. */
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if(ph->ph->phys == MAP_NONE) {
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struct cached_page *cp;
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u64_t referenced_offset =
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region->param.file.offset + ph->offset;
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if(region->param.file.fdref->ino == VMC_NO_INODE) {
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cp = find_cached_page_bydev(region->param.file.fdref->dev,
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referenced_offset, VMC_NO_INODE, 0, 1);
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} else {
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cp = find_cached_page_byino(region->param.file.fdref->dev,
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region->param.file.fdref->ino, referenced_offset, 1);
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}
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if(cp) {
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int result = OK;
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pb_unreferenced(region, ph, 0);
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pb_link(ph, cp->page, ph->offset, region);
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if(roundup(ph->offset+region->param.file.clearend,
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VM_PAGE_SIZE) >= region->length) {
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result = cow_block(vmp, region, ph,
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region->param.file.clearend);
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} else if(result == OK && write) {
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result = cow_block(vmp, region, ph, 0);
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}
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return result;
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}
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if(!cb) {
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printf("VM: mem_file: no callback, returning EFAULT\n");
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sys_sysctl_stacktrace(vmp->vm_endpoint);
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return EFAULT;
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}
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if(vfs_request(VMVFSREQ_FDIO, procfd, vmp, referenced_offset,
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VM_PAGE_SIZE, cb, NULL, state, statelen) != OK) {
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printf("VM: mappedfile_pagefault: vfs_request failed\n");
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return ENOMEM;
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}
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*io = 1;
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return SUSPEND;
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}
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if(!write) {
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printf("mappedfile_pagefault: nonwrite fault?\n");
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return EFAULT;
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}
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return cow_block(vmp, region, ph, 0);
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}
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static int mappedfile_sanitycheck(struct phys_region *pr, char *file, int line)
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{
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MYASSERT(usedpages_add(pr->ph->phys, VM_PAGE_SIZE) == OK);
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return OK;
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}
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static int mappedfile_writable(struct phys_region *pr)
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{
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/* We are never writable. */
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return 0;
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}
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int mappedfile_copy(struct vir_region *vr, struct vir_region *newvr)
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{
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assert(vr->param.file.inited);
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mappedfile_setfile(newvr->parent, newvr, vr->param.file.fdref->fd,
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vr->param.file.offset,
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vr->param.file.fdref->dev, vr->param.file.fdref->ino,
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vr->param.file.clearend, 0, 0);
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assert(newvr->param.file.inited);
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return OK;
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}
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int mappedfile_setfile(struct vmproc *owner,
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struct vir_region *region, int fd, u64_t offset,
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dev_t dev, ino_t ino, u16_t clearend, int prefill, int mayclosefd)
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{
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vir_bytes vaddr;
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struct fdref *newref;
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newref = fdref_dedup_or_new(owner, ino, dev, fd, mayclosefd);
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assert(newref);
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assert(!region->param.file.inited);
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assert(dev != NO_DEV);
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fdref_ref(newref, region);
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region->param.file.offset = offset;
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region->param.file.clearend = clearend;
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region->param.file.inited = 1;
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if(!prefill) return OK;
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for(vaddr = 0; vaddr < region->length; vaddr+=VM_PAGE_SIZE) {
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struct cached_page *cp = NULL;
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struct phys_region *pr;
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u64_t referenced_offset = offset + vaddr;
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if(roundup(vaddr+region->param.file.clearend,
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VM_PAGE_SIZE) >= region->length) {
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break;
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}
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if(ino == VMC_NO_INODE) {
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cp = find_cached_page_bydev(dev, referenced_offset,
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VMC_NO_INODE, 0, 1);
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} else {
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cp = find_cached_page_byino(dev, ino,
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referenced_offset, 1);
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}
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if(!cp) continue;
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if(!(pr = pb_reference(cp->page, vaddr, region,
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&mem_type_mappedfile))) {
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printf("mappedfile_setfile: pb_reference failed\n");
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break;
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}
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if(map_ph_writept(region->parent, region, pr) != OK) {
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printf("mappedfile_setfile: map_ph_writept failed\n");
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break;
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}
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}
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return OK;
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}
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static void mappedfile_split(struct vmproc *vmp, struct vir_region *vr,
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struct vir_region *r1, struct vir_region *r2)
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{
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assert(!r1->param.file.inited);
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assert(!r2->param.file.inited);
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assert(vr->param.file.inited);
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assert(r1->length + r2->length == vr->length);
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assert(vr->def_memtype == &mem_type_mappedfile);
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assert(r1->def_memtype == &mem_type_mappedfile);
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assert(r2->def_memtype == &mem_type_mappedfile);
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r1->param.file = vr->param.file;
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r2->param.file = vr->param.file;
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fdref_ref(vr->param.file.fdref, r1);
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fdref_ref(vr->param.file.fdref, r2);
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r1->param.file.clearend = 0;
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r2->param.file.offset += r1->length;
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assert(r1->param.file.inited);
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assert(r2->param.file.inited);
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}
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static int mappedfile_lowshrink(struct vir_region *vr, vir_bytes len)
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{
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assert(vr->param.file.inited);
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vr->param.file.offset += len;
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return OK;
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}
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static void mappedfile_delete(struct vir_region *region)
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{
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assert(region->def_memtype == &mem_type_mappedfile);
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assert(region->param.file.inited);
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assert(region->param.file.fdref);
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fdref_deref(region);
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region->param.file.inited = 0;
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}
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