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Change the vm_ooffset_t type to unsigned.

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The type represents byte offset in the vm_object_t data space, which
does not span negative offsets in FreeBSD VM.  The change matches byte
offset signess with the unsignedness of the vm_pindex_t which
represents the type of the page indexes in the objects.

This allows to remove the UOFF_TO_IDX() macro which was used when we
have to forcibly interpret the type as unsigned anyway.  Also it fixes
a lot of implicit bugs in the device drivers d_mmap methods.

Reviewed by:	alc, markj (previous version)
Tested by:	pho
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Konstantin Belousov 2018-12-02 13:16:46 +00:00
parent 200bf72793
commit 10d9120c44
6 changed files with 15 additions and 22 deletions
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8
sys/dev/xen/gntdev/gntdev.c
View File

@ -814,8 +814,8 @@ gntdev_gmap_pg_fault(vm_object_t object, vm_ooffset_t offset, int prot,
relative_offset = offset - gmap->file_index;
pidx = UOFF_TO_IDX(offset);
ridx = UOFF_TO_IDX(relative_offset);
pidx = OFF_TO_IDX(offset);
ridx = OFF_TO_IDX(relative_offset);
if (ridx >= gmap->count ||
gmap->grant_map_ops[ridx].status != GNTST_okay)
return (VM_PAGER_FAIL);
@ -1085,7 +1085,7 @@ mmap_gref(struct per_user_data *priv_user, struct gntdev_gref *gref_start,
break;
vm_page_insert(gref->page, mem_obj,
UOFF_TO_IDX(gref->file_index));
OFF_TO_IDX(gref->file_index));
count--;
}
@ -1225,7 +1225,7 @@ gntdev_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
if (error != 0)
return (EINVAL);
count = UOFF_TO_IDX(size);
count = OFF_TO_IDX(size);
gref_start = gntdev_find_grefs(priv_user, *offset, count);
if (gref_start) {

2
sys/sys/types.h
View File

@ -261,7 +261,7 @@ typedef __uint64_t kvaddr_t;
typedef __uint64_t ksize_t;
typedef __vm_offset_t vm_offset_t;
typedef __int64_t vm_ooffset_t;
typedef __uint64_t vm_ooffset_t;
typedef __vm_paddr_t vm_paddr_t;
typedef __uint64_t vm_pindex_t;
typedef __vm_size_t vm_size_t;

6
sys/vm/device_pager.c
View File

@ -150,9 +150,9 @@ cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
* of the page size. Do a check to avoid wrap.
*/
size = round_page(size);
pindex = UOFF_TO_IDX(foff) + UOFF_TO_IDX(size);
if (pindex > OBJ_MAX_SIZE || pindex < UOFF_TO_IDX(foff) ||
pindex < UOFF_TO_IDX(size))
pindex = OFF_TO_IDX(foff) + OFF_TO_IDX(size);
if (pindex > OBJ_MAX_SIZE || pindex < OFF_TO_IDX(foff) ||
pindex < OFF_TO_IDX(size))
return (NULL);
if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)

6
sys/vm/sg_pager.c
View File

@ -100,9 +100,9 @@ sg_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
* to map beyond that.
*/
size = round_page(size);
pindex = UOFF_TO_IDX(foff) + UOFF_TO_IDX(size);
if (pindex > npages || pindex < UOFF_TO_IDX(foff) ||
pindex < UOFF_TO_IDX(size))
pindex = OFF_TO_IDX(foff) + OFF_TO_IDX(size);
if (pindex > npages || pindex < OFF_TO_IDX(foff) ||
pindex < OFF_TO_IDX(size))
return (NULL);
/*

4
sys/vm/vm_map.c
View File

@ -4213,7 +4213,7 @@ vm_map_lookup(vm_map_t *var_map, /* IN/OUT */
* Return the object/offset from this entry. If the entry was
* copy-on-write or empty, it has been fixed up.
*/
*pindex = UOFF_TO_IDX((vaddr - entry->start) + entry->offset);
*pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
*object = entry->object.vm_object;
*out_prot = prot;
@ -4294,7 +4294,7 @@ vm_map_lookup_locked(vm_map_t *var_map, /* IN/OUT */
* Return the object/offset from this entry. If the entry was
* copy-on-write or empty, it has been fixed up.
*/
*pindex = UOFF_TO_IDX((vaddr - entry->start) + entry->offset);
*pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
*object = entry->object.vm_object;
*out_prot = prot;

11
sys/vm/vm_object.h
View File

@ -196,20 +196,13 @@ struct vm_object {
/*
* Helpers to perform conversion between vm_object page indexes and offsets.
* IDX_TO_OFF() converts an index into an offset.
* OFF_TO_IDX() converts an offset into an index. Since offsets are signed
* by default, the sign propagation in OFF_TO_IDX(), when applied to
* negative offsets, is intentional and returns a vm_object page index
* that cannot be created by a userspace mapping.
* UOFF_TO_IDX() treats the offset as an unsigned value and converts it
* into an index accordingly. Use it only when the full range of offset
* values are allowed. Currently, this only applies to device mappings.
* OFF_TO_IDX() converts an offset into an index.
* OBJ_MAX_SIZE specifies the maximum page index corresponding to the
* maximum unsigned offset.
*/
#define IDX_TO_OFF(idx) (((vm_ooffset_t)(idx)) << PAGE_SHIFT)
#define OFF_TO_IDX(off) ((vm_pindex_t)(((vm_ooffset_t)(off)) >> PAGE_SHIFT))
#define UOFF_TO_IDX(off) (((vm_pindex_t)(off)) >> PAGE_SHIFT)
#define OBJ_MAX_SIZE (UOFF_TO_IDX(UINT64_MAX) + 1)
#define OBJ_MAX_SIZE (OFF_TO_IDX(UINT64_MAX) + 1)
#ifdef _KERNEL