From: Christoph Hellwig <hch@lst.de>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [PATCH v8 03/10] iomap: Complete partial direct I/O writes synchronously
Date: Wed, 6 Jun 2018 12:26:13 +0200 [thread overview]
Message-ID: <20180606102613.GA11138@lst.de> (raw)
In-Reply-To: <20180605121024.t6indzioavvfonxk@twin.jikos.cz>
On Tue, Jun 05, 2018 at 02:10:24PM +0200, David Sterba wrote:
> On Mon, Jun 04, 2018 at 09:31:16PM +0200, Andreas Gruenbacher wrote:
> > @@ -1062,8 +1063,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> > if (ret < 0)
> > iomap_dio_set_error(dio, ret);
> >
> > + smp_mb__before_atomic();
> > if (!atomic_dec_and_test(&dio->ref)) {
>
> The barrier should be documented. I tried to do a quick look around the
> code if it's clear why it's there but it's not. Thanks.
It doesn't really make sense. smp_mb__before_atomic is for relaxed
atomic operations, which atomic_dec_and_test is not.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: David Sterba <dsterba@suse.cz>
Cc: Andreas Gruenbacher <agruenba@redhat.com>,
cluster-devel@redhat.com, Christoph Hellwig <hch@lst.de>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v8 03/10] iomap: Complete partial direct I/O writes synchronously
Date: Wed, 6 Jun 2018 12:26:13 +0200 [thread overview]
Message-ID: <20180606102613.GA11138@lst.de> (raw)
In-Reply-To: <20180605121024.t6indzioavvfonxk@twin.jikos.cz>
On Tue, Jun 05, 2018 at 02:10:24PM +0200, David Sterba wrote:
> On Mon, Jun 04, 2018 at 09:31:16PM +0200, Andreas Gruenbacher wrote:
> > @@ -1062,8 +1063,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> > if (ret < 0)
> > iomap_dio_set_error(dio, ret);
> >
> > + smp_mb__before_atomic();
> > if (!atomic_dec_and_test(&dio->ref)) {
>
> The barrier should be documented. I tried to do a quick look around the
> code if it's clear why it's there but it's not. Thanks.
It doesn't really make sense. smp_mb__before_atomic is for relaxed
atomic operations, which atomic_dec_and_test is not.
next prev parent reply other threads:[~2018-06-06 10:26 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-04 19:31 [Cluster-devel] [PATCH v8 00/10] gfs2 iomap write support Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 01/10] iomap: inline data should be an iomap type, not a flag Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 02/10] iomap: Mark newly allocated buffer heads as new Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 03/10] iomap: Complete partial direct I/O writes synchronously Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-05 12:10 ` [Cluster-devel] " David Sterba
2018-06-05 12:10 ` David Sterba
2018-06-05 12:32 ` [Cluster-devel] " Andreas Grünbacher
2018-06-05 12:32 ` Andreas Grünbacher
2018-06-06 10:26 ` Christoph Hellwig [this message]
2018-06-06 10:26 ` Christoph Hellwig
2018-06-06 11:44 ` [Cluster-devel] " Andreas Gruenbacher
2018-06-06 11:44 ` Andreas Gruenbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 04/10] fs: factor out a __generic_write_end helper Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 05/10] iomap: Generic inline data handling Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-05 5:34 ` [Cluster-devel] " Christoph Hellwig
2018-06-05 5:34 ` Christoph Hellwig
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 06/10] iomap: Add page_write_end iomap hook Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-05 7:56 ` [Cluster-devel] " Andreas Grünbacher
2018-06-05 7:56 ` Andreas Grünbacher
2018-06-05 12:07 ` [Cluster-devel] " David Sterba
2018-06-05 12:07 ` David Sterba
2018-06-05 12:17 ` [Cluster-devel] " Andreas Grünbacher
2018-06-05 12:17 ` Andreas Grünbacher
2018-06-05 12:29 ` [Cluster-devel] " David Sterba
2018-06-05 12:29 ` David Sterba
2018-06-05 12:50 ` [Cluster-devel] " Andreas Grünbacher
2018-06-05 12:50 ` Andreas Grünbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 07/10] gfs2: iomap buffered write support Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 08/10] gfs2: gfs2_extent_length cleanup Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 09/10] gfs2: iomap direct I/O support Andreas Gruenbacher
2018-06-04 19:31 ` Andreas Gruenbacher
2018-06-04 19:31 ` [Cluster-devel] [PATCH v8 10/10] gfs2: Remove gfs2_write_{begin, end} Andreas Gruenbacher
2018-06-04 19:31 ` [PATCH v8 10/10] gfs2: Remove gfs2_write_{begin,end} Andreas Gruenbacher
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