[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 2/5] lock-guard: add scoped lock implementation
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH 2/5] lock-guard: add scoped lock implementation |
Date: |
Mon, 11 Dec 2017 07:51:43 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
On 12/11/2017 04:16 AM, Stefan Hajnoczi wrote:
>>> I don't understand the need for the qemu_lock_guard_is_taken(&name)
>>> condition, why not do the following?
>>>
>>> for (QEMU_LOCK_GUARD(type, name, lock);
>>> ;
>>> qemu_lock_guard_unlock(&name))
>>
>> Because that would be an infinite loop. :)
>
> Sorry, I mean for (...; false; ...). Is there any reason to do
> qemu_lock_guard_is_taken(&name)?
You need the loop to execute at least once ;)
But I proposed an alternative that doesn't need is_taken, by:
for (bool name##done = false, QEMU_LOCK_GUARD(type, name, lock);
! name##done; name##done = true)
if we still like the form that declares a for-loop scope.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
signature.asc
Description: OpenPGP digital signature
[Qemu-devel] [PATCH 3/5] qemu-timer: convert to use lock guards, Paolo Bonzini, 2017/12/08
[Qemu-devel] [PATCH 4/5] qht: convert to use lock guards, Paolo Bonzini, 2017/12/08
[Qemu-devel] [PATCH 5/5] thread-pool: convert to use lock guards, Paolo Bonzini, 2017/12/08