diff mbox series

[v2,1/5] bitops: introduce change_bit_atomic

Message ID 20181106122025.3487-2-xiaoguangrong@tencent.com (mailing list archive)
State New, archived
Headers show
Series migration: improve multithreads | expand

Commit Message

Xiao Guangrong Nov. 6, 2018, 12:20 p.m. UTC 
From: Xiao Guangrong <xiaoguangrong@tencent.com>

It will be used by threaded workqueue

Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>
---
 include/qemu/bitops.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)
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Patch

diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
index 3f0926cf40..c522958852 100644
--- a/include/qemu/bitops.h
+++ b/include/qemu/bitops.h
@@ -79,6 +79,19 @@  static inline void change_bit(long nr, unsigned long *addr)
     *p ^= mask;
 }
 
+/**
+ * change_bit_atomic - Toggle a bit in memory atomically
+ * @nr: Bit to change
+ * @addr: Address to start counting from
+ */
+static inline void change_bit_atomic(long nr, unsigned long *addr)
+{
+    unsigned long mask = BIT_MASK(nr);
+    unsigned long *p = addr + BIT_WORD(nr);
+
+    atomic_xor(p, mask);
+}
+
 /**
  * test_and_set_bit - Set a bit and return its old value
  * @nr: Bit to set