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[v3,1/2] QSLIST: add atomic replace operation

Message ID 20201016112640.91141-1-wanghonghao@bytedance.com
State New
Headers show
Series [v3,1/2] QSLIST: add atomic replace operation | expand

Commit Message

王洪浩 Oct. 16, 2020, 11:26 a.m. UTC 
Replace a queue with another atomicly. It's useful when we need to transfer
queues between threads.

Signed-off-by: wanghonghao <wanghonghao@bytedance.com>
---
 include/qemu/queue.h | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

diff --git a/include/qemu/queue.h b/include/qemu/queue.h
index e029e7bf66..1f0cbdf87e 100644
--- a/include/qemu/queue.h
+++ b/include/qemu/queue.h
@@ -226,6 +226,10 @@  struct {                                                                \
         (dest)->slh_first = qatomic_xchg(&(src)->slh_first, NULL);       \
 } while (/*CONSTCOND*/0)
 
+#define QSLIST_REPLACE_ATOMIC(dest, src, old) do {                            \
+        (old)->slh_first = qatomic_xchg(&(dest)->slh_first, (src)->slh_first); \
+} while (/*CONSTCOND*/0)
+
 #define QSLIST_REMOVE_HEAD(head, field) do {                             \
         typeof((head)->slh_first) elm = (head)->slh_first;               \
         (head)->slh_first = elm->field.sle_next;                         \