diff mbox series

[v3,1/5] bitops: introduce change_bit_atomic

Message ID 20181122072028.22819-2-xiaoguangrong@tencent.com (mailing list archive)
State New, archived
Headers show
Series migration: improve multithreads | expand

Commit Message

Xiao Guangrong Nov. 22, 2018, 7:20 a.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(+)

Comments

Dr. David Alan Gilbert Nov. 23, 2018, 10:23 a.m. UTC | #1 
* guangrong.xiao@gmail.com (guangrong.xiao@gmail.com) wrote:
> From: Xiao Guangrong <xiaoguangrong@tencent.com>
> 
> It will be used by threaded workqueue
> 
> Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  include/qemu/bitops.h | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> 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
> -- 
> 2.14.5
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
Juan Quintela Nov. 28, 2018, 9:35 a.m. UTC | #2 
guangrong.xiao@gmail.com wrote:
> From: Xiao Guangrong <xiaoguangrong@tencent.com>
>
> It will be used by threaded workqueue
>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>
diff mbox series

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