* [PATCH] migration: Simplify get_qlist
@ 2020-01-25 17:24 Eric Auger
2020-01-27 11:48 ` Juan Quintela
0 siblings, 1 reply; 2+ messages in thread
From: Eric Auger @ 2020-01-25 17:24 UTC (permalink / raw)
To: eric.auger.pro, eric.auger, qemu-devel, dgilbert, quintela; +Cc: peterx
Instead of inserting read elements at the head and
then reversing the list, it is simpler to add
each element after the previous one. Introduce
QLIST_RAW_INSERT_AFTER helper and use it in
get_qlist().
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Suggested-by: Juan Quintela <quintela@redhat.com>
---
---
include/qemu/queue.h | 19 ++++++-------------
migration/vmstate-types.c | 10 +++++++---
2 files changed, 13 insertions(+), 16 deletions(-)
diff --git a/include/qemu/queue.h b/include/qemu/queue.h
index 4d4554a7ce..19425f973f 100644
--- a/include/qemu/queue.h
+++ b/include/qemu/queue.h
@@ -515,6 +515,12 @@ union { \
(elm); \
(elm) = *QLIST_RAW_NEXT(elm, entry))
+#define QLIST_RAW_INSERT_AFTER(head, prev, elem, entry) do { \
+ *QLIST_RAW_NEXT(prev, entry) = elem; \
+ *QLIST_RAW_PREVIOUS(elem, entry) = QLIST_RAW_NEXT(prev, entry); \
+ *QLIST_RAW_NEXT(elem, entry) = NULL; \
+} while (0)
+
#define QLIST_RAW_INSERT_HEAD(head, elm, entry) do { \
void *first = *QLIST_RAW_FIRST(head); \
*QLIST_RAW_FIRST(head) = elm; \
@@ -527,17 +533,4 @@ union { \
} \
} while (0)
-#define QLIST_RAW_REVERSE(head, elm, entry) do { \
- void *iter = *QLIST_RAW_FIRST(head), *prev = NULL, *next; \
- while (iter) { \
- next = *QLIST_RAW_NEXT(iter, entry); \
- *QLIST_RAW_PREVIOUS(iter, entry) = QLIST_RAW_NEXT(next, entry); \
- *QLIST_RAW_NEXT(iter, entry) = prev; \
- prev = iter; \
- iter = next; \
- } \
- *QLIST_RAW_FIRST(head) = prev; \
- *QLIST_RAW_PREVIOUS(prev, entry) = QLIST_RAW_FIRST(head); \
-} while (0)
-
#endif /* QEMU_SYS_QUEUE_H */
diff --git a/migration/vmstate-types.c b/migration/vmstate-types.c
index 1eee36773a..35e784c9d9 100644
--- a/migration/vmstate-types.c
+++ b/migration/vmstate-types.c
@@ -879,7 +879,7 @@ static int get_qlist(QEMUFile *f, void *pv, size_t unused_size,
/* offset of the QLIST entry in a QLIST element */
size_t entry_offset = field->start;
int version_id = field->version_id;
- void *elm;
+ void *elm, *prev = NULL;
trace_get_qlist(field->name, vmsd->name, vmsd->version_id);
if (version_id > vmsd->version_id) {
@@ -900,9 +900,13 @@ static int get_qlist(QEMUFile *f, void *pv, size_t unused_size,
g_free(elm);
return ret;
}
- QLIST_RAW_INSERT_HEAD(pv, elm, entry_offset);
+ if (!prev) {
+ QLIST_RAW_INSERT_HEAD(pv, elm, entry_offset);
+ } else {
+ QLIST_RAW_INSERT_AFTER(pv, prev, elm, entry_offset);
+ }
+ prev = elm;
}
- QLIST_RAW_REVERSE(pv, elm, entry_offset);
trace_get_qlist_end(field->name, vmsd->name);
return ret;
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] migration: Simplify get_qlist
2020-01-25 17:24 [PATCH] migration: Simplify get_qlist Eric Auger
@ 2020-01-27 11:48 ` Juan Quintela
0 siblings, 0 replies; 2+ messages in thread
From: Juan Quintela @ 2020-01-27 11:48 UTC (permalink / raw)
To: Eric Auger; +Cc: peterx, qemu-devel, dgilbert, eric.auger.pro
Eric Auger <eric.auger@redhat.com> wrote:
> Instead of inserting read elements at the head and
> then reversing the list, it is simpler to add
> each element after the previous one. Introduce
> QLIST_RAW_INSERT_AFTER helper and use it in
> get_qlist().
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Suggested-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
It wis really suggested by Dave, I just gave a sample implementation
O:-)
Later, Juan.
^ permalink raw reply [flat|nested] 2+ messages in thread
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