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Date: Fri, 5 May 2017 18:19:55 +0800
From: Fam Zheng <famz@redhat.com>
Message-ID: <20170505101955.GG21435@lemon.lan>
References: <20170505100255.11145-1-stefanha@redhat.com>
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In-Reply-To: <20170505100255.11145-1-stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2] aio: add missing aio_notify() to
 aio_enable_external()
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To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>

On Fri, 05/05 11:02, Stefan Hajnoczi wrote:
> diff --git a/include/block/aio.h b/include/block/aio.h
> index 406e323..b3d6f76 100644
> --- a/include/block/aio.h
> +++ b/include/block/aio.h
> @@ -454,8 +454,14 @@ static inline void aio_disable_external(AioContext *ctx)
>   */
>  static inline void aio_enable_external(AioContext *ctx)
>  {
> -    assert(ctx->external_disable_cnt > 0);
> -    atomic_dec(&ctx->external_disable_cnt);
> +    int old;
> +
> +    old = atomic_dec_fetch(&ctx->external_disable_cnt);

Did you mean atomic_fetch_dec? atomic_dec_fetch is new, not old.

> +    assert(old > 0);
> +    if (old == 1) {
> +        /* Kick event loop so it re-arms file descriptors */
> +        aio_notify(ctx);
> +    }
>  }
>  
>  /**
> -- 
> 2.9.3
>