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Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lo
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant |
Date: |
Wed, 11 Sep 2019 19:27:09 +0100 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
* Eric Blake (address@hidden) wrote:
> On 9/11/19 12:40 PM, Eric Blake wrote:
>
> >> +
> >> +#define RCU_READ_LOCK_AUTO g_auto(rcu_read_auto_t) \
> >> + _rcu_read_auto = 'x'; \
> >
> > I'm a bit lost at where _rcu_read_auto is declared. (I could understand
> > if an earlier macro had created that typedef via concatenating _ with
> > rcu_read_auto_t, but making the preprocessor drop _t is not possible. Is
> > this a typo, and if so, why did the compiler not complain?)
>
> Okay, I read it wrong. This rendering would be easier for me to
> understand (you are declaring a dummy variable right here):
>
> #define RCU_READ_LOCK_AUTO \
> g_auto(rcu_read_auto_t) _rcu_read_auto = 'x'; \
> ...
>
> In other words, I'm not used to expecting a split between type and
> variable name across two lines, especially when the type is itself a
> macro call, and where my first reading didn't spot that
> (rcu_read_auto_t) was not the name of the argument to a mixed-case macro
> RCU_READ_LOACK_AUTO_g_auto, rather than g_auto(...) being the start of
> the parameter-less macro RCU_READ_LOCK_AUTO definition.
Yep, that's simplified after the rework Dan suggested.
Dave
> --
> Eric Blake, Principal Software Engineer
> Red Hat, Inc. +1-919-301-3226
> Virtualization: qemu.org | libvirt.org
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, (continued)
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Daniel P . Berrangé, 2019/09/11
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Dr. David Alan Gilbert, 2019/09/11
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Daniel P . Berrangé, 2019/09/11
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Dr. David Alan Gilbert, 2019/09/11
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Daniel P . Berrangé, 2019/09/11
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Dr. David Alan Gilbert, 2019/09/11
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Eric Blake, 2019/09/11
- Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Dr. David Alan Gilbert, 2019/09/11
Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Eric Blake, 2019/09/11
Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant, Dr. David Alan Gilbert, 2019/09/11
[Qemu-devel] [PATCH 2/3] migration: Use automatic rcu_read unlock in ram.c, Dr. David Alan Gilbert (git), 2019/09/11
[Qemu-devel] [PATCH 3/3] migration: Use automatic rcu_read unlock in rdma.c, Dr. David Alan Gilbert (git), 2019/09/11
Re: [Qemu-devel] [PATCH 0/3] Automatic RCU read unlock, Daniel P . Berrangé, 2019/09/11
Re: [Qemu-devel] [PATCH 0/3] Automatic RCU read unlock, no-reply, 2019/09/11