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Re: [Qemu-devel] [PATCH v2 1/4] exec: Atomic access to bounce buffer
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From: |
Paolo Bonzini |
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Subject: |
Re: [Qemu-devel] [PATCH v2 1/4] exec: Atomic access to bounce buffer |
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Date: |
Fri, 13 Mar 2015 09:32:06 +0100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 |
On 13/03/2015 09:16, Fam Zheng wrote:
>>> > > + if (atomic_cmpxchg(&bounce.in_use, false, true)) {
>> >
>> > atomic_or is enough...
> atomic_cmpxchg is here to take the ownership of bounce iff it is not in use,
> so
> I think it is necessary.
It's changing false to true and true to true, so you can do
if (atomic_or(&bounce.in_use, 1)) {
// was true already
}
Paolo
[Qemu-devel] [PATCH v2 1/4] exec: Atomic access to bounce buffer, Fam Zheng, 2015/03/12
[Qemu-devel] [PATCH v2 2/4] exec: Atomic access to map_client_list, Fam Zheng, 2015/03/12
[Qemu-devel] [PATCH v2 3/4] exec: Notify cpu_register_map_client caller if the bounce buffer is available, Fam Zheng, 2015/03/12