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From: Bart Van Assche <Bart.VanAssche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
To: "jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org"
	<jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>,
	"linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Cc: "sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org"
	<sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH rdma-core 4/6] rdmacm: Use C11 stdatomic for all atomics
Date: Wed, 15 Mar 2017 22:55:52 +0000	[thread overview]
Message-ID: <1489618538.2660.14.camel@sandisk.com> (raw)
In-Reply-To: <1489615927-12117-5-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>

On Wed, 2017-03-15 at 16:12 -0600, Jason Gunthorpe wrote:
> @@ -1013,7 +1012,7 @@ int close(int socket)
>  			return ret;
>  	}
>  
> -	if (atomic_dec(&fdi->refcnt))
> +	if (atomic_fetch_sub(&fdi->refcnt, 1))
>  		return 0;
>  
>  	idm_clear(&idm, socket);
> @@ -898,7 +898,7 @@ static int rs_create_ep(struct rsocket *rs)
>  
>  static void rs_release_iomap_mr(struct rs_iomap_mr *iomr)
>  {
> -	if (atomic_dec(&iomr->refcnt))
> +	if (atomic_fetch_sub(&iomr->refcnt, 1))
>  		return;
>  
>  	dlist_remove(&iomr->entry);

Hello Jason,

In the gcc documentation I read that __sync_sub_and_fetch() (used to
implement atomic_dec()) returns the new value. In the C11 standard I read
that atomic_fetch_sub() returns the old value. Do you agree with this?

Thanks,

Bart.--
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  parent reply	other threads:[~2017-03-15 22:55 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-15 22:12 [PATCH rdma-core 0/6] Sparse code changes Jason Gunthorpe
     [not found] ` <1489615927-12117-1-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-15 22:12   ` [PATCH rdma-core 1/6] Use NULL instead of 0 to silence sparse Jason Gunthorpe
2017-03-15 22:12   ` [PATCH rdma-core 2/6] INADDR_* needs to be byteswapped before being used Jason Gunthorpe
2017-03-15 22:12   ` [PATCH rdma-core 3/6] rstream: Use waitpid instead of wait Jason Gunthorpe
2017-03-15 22:12   ` [PATCH rdma-core 4/6] rdmacm: Use C11 stdatomic for all atomics Jason Gunthorpe
     [not found]     ` <1489615927-12117-5-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-15 22:55       ` Bart Van Assche [this message]
     [not found]         ` <1489618538.2660.14.camel-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2017-03-15 23:18           ` Jason Gunthorpe
     [not found]             ` <20170315231837.GA23082-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-16  1:04               ` Bart Van Assche
     [not found]                 ` <1489626275.3542.1.camel-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2017-03-16 16:16                   ` Jason Gunthorpe
2017-03-15 22:12   ` [PATCH rdma-core 5/6] rsocket: Fix byte swapping when constructing path records Jason Gunthorpe
2017-03-15 22:12   ` [PATCH rdma-core 6/6] verbs: Consistently apply __attribute_const Jason Gunthorpe
2017-03-21 17:24   ` [PATCH rdma-core 0/6] Sparse code changes Doug Ledford

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