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[Qemu-devel] [RFC PATCH v2 6/8] migration/vmstate: split up vmstate_base
From: |
Halil Pasic |
Subject: |
[Qemu-devel] [RFC PATCH v2 6/8] migration/vmstate: split up vmstate_base_addr |
Date: |
Tue, 8 Nov 2016 10:56:01 +0100 |
Currently vmstate_base_addr does several things: it pinpoints the field
within the struct, possibly allocates memory and possibly does the first
pointer dereference. Obviously allocation is needed only for load.
Let us split up the functionality in vmstate_base_addr and move the
address manipulations (that is everything but the allocation logic) to
load and save so it becomes more obvious what is actually going on. Like
this all the address calculations (and the handling of the flags
controlling these) is in one place and the sequence is more obvious.
The newly introduced function vmstate_handle_alloc also fixes the
allocation for the unused VMS_VBUFFER| VMS_MULTIPLY scenario and is
substantially simpler than the original vmstate_base_addr.
In load and save some asserts are added so it's easier to debug
situations where we would end up with a null pointer dereference.
Signed-off-by: Halil Pasic <address@hidden>
---
migration/vmstate.c | 41 ++++++++++++++++++-----------------------
1 file changed, 18 insertions(+), 23 deletions(-)
diff --git a/migration/vmstate.c b/migration/vmstate.c
index a86fb7e..10a7645 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -50,29 +50,15 @@ static int vmstate_size(void *opaque, VMStateField *field)
return size;
}
-static void *vmstate_base_addr(void *opaque, VMStateField *field, bool alloc)
-{
- void *base_addr = opaque + field->offset;
-
- if (field->flags & VMS_POINTER) {
- if (alloc && (field->flags & VMS_ALLOC)) {
- gsize size = 0;
- if (field->flags & VMS_VBUFFER) {
- size = vmstate_size(opaque, field);
- } else {
- int n_elems = vmstate_n_elems(opaque, field);
- if (n_elems) {
- size = n_elems * field->size;
- }
- }
- if (size) {
- *(void **)base_addr = g_malloc(size);
- }
+static void vmstate_handle_alloc(void *ptr, VMStateField *field, void *opaque)
+{
+ if (field->flags & VMS_POINTER && field->flags & VMS_ALLOC) {
+ gsize size = vmstate_size(opaque, field);
+ size *= vmstate_n_elems(opaque, field);
+ if (size) {
+ *(void **)ptr = g_malloc(size);
}
- base_addr = *(void **)base_addr;
}
-
- return base_addr;
}
int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
@@ -108,10 +94,15 @@ int vmstate_load_state(QEMUFile *f, const
VMStateDescription *vmsd,
field->field_exists(opaque, version_id)) ||
(!field->field_exists &&
field->version_id <= version_id)) {
- void *first_elem = vmstate_base_addr(opaque, field, true);
+ void *first_elem = opaque + field->offset;
int i, n_elems = vmstate_n_elems(opaque, field);
int size = vmstate_size(opaque, field);
+ vmstate_handle_alloc(first_elem, field, opaque);
+ if (field->flags & VMS_POINTER) {
+ first_elem = *(void **)first_elem;
+ assert(first_elem);
+ }
for (i = 0; i < n_elems; i++) {
void *curr_elem = first_elem + size * i;
@@ -310,12 +301,16 @@ void vmstate_save_state(QEMUFile *f, const
VMStateDescription *vmsd,
while (field->name) {
if (!field->field_exists ||
field->field_exists(opaque, vmsd->version_id)) {
- void *first_elem = vmstate_base_addr(opaque, field, false);
+ void *first_elem = opaque + field->offset;
int i, n_elems = vmstate_n_elems(opaque, field);
int size = vmstate_size(opaque, field);
int64_t old_offset, written_bytes;
QJSON *vmdesc_loop = vmdesc;
+ if (field->flags & VMS_POINTER) {
+ first_elem = *(void **)first_elem;
+ assert(first_elem);
+ }
for (i = 0; i < n_elems; i++) {
void *curr_elem = first_elem + size * i;
--
2.8.4
- [Qemu-devel] [RFC PATCH v2 0/8] VMS_ARRAY_OF_POINTER with null pointers, Halil Pasic, 2016/11/08
- [Qemu-devel] [RFC PATCH v2 4/8] tests/test-vmstate.c: add array of pointer to struct, Halil Pasic, 2016/11/08
- [Qemu-devel] [RFC PATCH v2 1/8] tests/test-vmstate.c: add vBuffer test, Halil Pasic, 2016/11/08
- [Qemu-devel] [RFC PATCH v2 7/8] migration/vmstate: fix array of pointers to struct, Halil Pasic, 2016/11/08
- [Qemu-devel] [RFC PATCH v2 8/8] tests/test-vmstate.c: add array of pointers to struct with NULL, Halil Pasic, 2016/11/08
- [Qemu-devel] [RFC PATCH v2 3/8] tests/test-vmstate.c: add save_buffer util func, Halil Pasic, 2016/11/08
- [Qemu-devel] [RFC PATCH v2 2/8] migration: drop unused VMStateField.start, Halil Pasic, 2016/11/08
- [Qemu-devel] [RFC PATCH v2 5/8] migration/vmstate: renames in (load|save)_state, Halil Pasic, 2016/11/08
- [Qemu-devel] [RFC PATCH v2 6/8] migration/vmstate: split up vmstate_base_addr,
Halil Pasic <=