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cleanup madvise code, add a few more sanity checks.

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Reviewed by:	Alan Cox <alc@cs.rice.edu>,  dg@root.com
This commit is contained in:
Matthew Dillon 1999-09-21 05:00:48 +00:00
parent 2b635927ac
commit b430905573
3 changed files with 88 additions and 49 deletions
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116
sys/vm/vm_map.c
View File

@ -1009,31 +1009,51 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
* the vm_map_entry structure, or those effecting the underlying
* objects.
*/
void
int
vm_map_madvise(map, start, end, behav)
vm_map_t map;
vm_offset_t start, end;
int behav;
{
vm_map_entry_t current, entry;
int modify_map;
int modify_map = 0;
modify_map = (behav == MADV_NORMAL || behav == MADV_SEQUENTIAL ||
behav == MADV_RANDOM);
/*
* Some madvise calls directly modify the vm_map_entry, in which case
* we need to use an exclusive lock on the map and we need to perform
* various clipping operations. Otherwise we only need a read-lock
* on the map.
*/
if (modify_map) {
switch(behav) {
case MADV_NORMAL:
case MADV_SEQUENTIAL:
case MADV_RANDOM:
modify_map = 1;
vm_map_lock(map);
}
else
break;
case MADV_WILLNEED:
case MADV_DONTNEED:
case MADV_FREE:
vm_map_lock_read(map);
break;
default:
return (KERN_INVALID_ARGUMENT);
}
/*
* Locate starting entry and clip if necessary.
*/
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry)) {
if (modify_map)
vm_map_clip_start(map, entry, start);
} else
} else {
entry = entry->next;
}
if (modify_map) {
/*
@ -1044,8 +1064,8 @@ vm_map_madvise(map, start, end, behav)
*/
for (current = entry;
(current != &map->header) && (current->start < end);
current = current->next) {
current = current->next
) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
@ -1067,51 +1087,53 @@ vm_map_madvise(map, start, end, behav)
vm_map_simplify_entry(map, current);
}
vm_map_unlock(map);
}
else {
if (behav == MADV_FREE || behav == MADV_DONTNEED ||
behav == MADV_WILLNEED) {
vm_pindex_t pindex;
int count;
} else {
vm_pindex_t pindex;
int count;
/*
* madvise behaviors that are implemented in the underlying
* vm_object.
*
* Since we don't clip the vm_map_entry, we have to clip
* the vm_object pindex and count.
*/
for (current = entry;
(current != &map->header) && (current->start < end);
current = current->next) {
/*
* madvise behaviors that are implemented in the underlying
* vm_object.
*
* Since we don't clip the vm_map_entry, we have to clip
* the vm_object pindex and count.
*/
for (current = entry;
(current != &map->header) && (current->start < end);
current = current->next
) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
pindex = OFF_TO_IDX(current->offset);
count = atop(current->end - current->start);
pindex = OFF_TO_IDX(current->offset);
count = atop(current->end - current->start);
if (current->start < start) {
pindex += atop(start - current->start);
count -= atop(start - current->start);
}
if (current->end > end)
count -= atop(current->end - end);
if (current->start < start) {
pindex += atop(start - current->start);
count -= atop(start - current->start);
}
if (current->end > end)
count -= atop(current->end - end);
if (count <= 0)
continue;
if (count <= 0)
continue;
vm_object_madvise(current->object.vm_object,
pindex, count, behav);
if (behav == MADV_WILLNEED)
pmap_object_init_pt(map->pmap, current->start,
current->object.vm_object,
pindex, (count << PAGE_SHIFT),
0);
vm_object_madvise(current->object.vm_object,
pindex, count, behav);
if (behav == MADV_WILLNEED) {
pmap_object_init_pt(
map->pmap,
current->start,
current->object.vm_object,
pindex,
(count << PAGE_SHIFT),
0
);
}
}
vm_map_unlock_read(map);
}
return(0);
}
@ -2764,12 +2786,14 @@ vm_uiomove(mapa, srcobject, cp, cnta, uaddra, npages)
TAILQ_REMOVE(&oldobject->shadow_head,
first_object, shadow_list);
oldobject->shadow_count--;
/* XXX bump generation? */
vm_object_deallocate(oldobject);
}
TAILQ_INSERT_TAIL(&srcobject->shadow_head,
first_object, shadow_list);
srcobject->shadow_count++;
/* XXX bump generation? */
first_object->backing_object = srcobject;
}

2
sys/vm/vm_map.h
View File

@ -361,7 +361,7 @@ int vm_map_protect __P((vm_map_t, vm_offset_t, vm_offset_t, vm_prot_t, boolean_t
int vm_map_remove __P((vm_map_t, vm_offset_t, vm_offset_t));
void vm_map_startup __P((void));
int vm_map_submap __P((vm_map_t, vm_offset_t, vm_offset_t, vm_map_t));
void vm_map_madvise __P((vm_map_t, vm_offset_t, vm_offset_t, int));
int vm_map_madvise __P((vm_map_t, vm_offset_t, vm_offset_t, int));
void vm_map_simplify_entry __P((vm_map_t, vm_map_entry_t));
void vm_init2 __P((void));
int vm_uiomove __P((vm_map_t, vm_object_t, off_t, int, vm_offset_t, int *));

19
sys/vm/vm_mmap.c
View File

@ -136,6 +136,15 @@ ogetpagesize(p, uap)
* modulo the PAGE_SIZE (POSIX 1003.1b). If the address is not
* page-aligned, the actual mapping starts at trunc_page(addr)
* and the return value is adjusted up by the page offset.
*
* Generally speaking, only character devices which are themselves
* memory-based, such as a video framebuffer, can be mmap'd. Otherwise
* there would be no cache coherency between a descriptor and a VM mapping
* both to the same character device.
*
* Block devices can be mmap'd no matter what they represent. Cache coherency
* is maintained as long as you do not write directly to the underlying
* character device.
*/
#ifndef _SYS_SYSPROTO_H_
struct mmap_args {
@ -615,6 +624,12 @@ madvise(p, uap)
struct madvise_args *uap;
{
vm_offset_t start, end;
/*
* Check for illegal behavior
*/
if (uap->behav < 0 || uap->behav > MADV_FREE)
return (EINVAL);
/*
* Check for illegal addresses. Watch out for address wrap... Note
* that VM_*_ADDRESS are not constants due to casts (argh).
@ -636,8 +651,8 @@ madvise(p, uap)
start = trunc_page((vm_offset_t) uap->addr);
end = round_page((vm_offset_t) uap->addr + uap->len);
vm_map_madvise(&p->p_vmspace->vm_map, start, end, uap->behav);
if (vm_map_madvise(&p->p_vmspace->vm_map, start, end, uap->behav))
return (EINVAL);
return (0);
}