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From: Joe Perches <joe@perches.com>
To: paulmck@linux.vnet.ibm.com
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
	jiangshanlai@gmail.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	fweisbec@gmail.com, oleg@redhat.com,
	Andy Whitcroft <apw@canonical.com>
Subject: Re: [PATCH tip/core/rcu 20/21] checkpatch: Add warnings for {smp_,}read_barrier_depends()
Date: Fri, 01 Dec 2017 20:45:13 -0800	[thread overview]
Message-ID: <1512189913.19952.184.camel@perches.com> (raw)
In-Reply-To: <20171201214416.GJ7829@linux.vnet.ibm.com>

On Fri, 2017-12-01 at 13:44 -0800, Paul E. McKenney wrote:
> On Fri, Dec 01, 2017 at 12:14:17PM -0800, Joe Perches wrote:
> > On Fri, 2017-12-01 at 11:51 -0800, Paul E. McKenney wrote:
> > > Now that both smp_read_barrier_depends() and read_barrier_depends()
> > > are being de-emphasized, warn if any are added.
> > 
> > This would also warn on existing files when run
> > with ./scripts/checkpatch.pl -f <file>
> > 
> > Do you want it to check new patches only?
> > 
> > If so the test could become "if (!$file && etc...)
> > 
> > > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> > > @@ -5586,6 +5586,12 @@ sub process {
> > >  			}
> > >  		}
> > >  
> > > +# check for smp_read_barrier_depends and read_barrier_depends
> > > +		if ($line =~ /\b(smp_|)read_barrier_depends\(/) {
> > 
> > Must become
> > 
> > +		if ($line =~ /\b(smp_|)read_barrier_depends\s*\(/) {
> > 
> > similar to the lines above this as there are sometimes
> > spaces between function name and argument parentheses.
> 
> Good points!  Like this?
[]
> commit ff155ce179aab891dbe2ca80f82a453383fd165a
> Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Date:   Mon Nov 27 09:37:35 2017 -0800
> 
>     checkpatch: Add warnings for {smp_,}read_barrier_depends()
>     
>     Now that both smp_read_barrier_depends() and read_barrier_depends()
>     are being de-emphasized, warn if any are added.
>     
>     Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>     Cc: Andy Whitcroft <apw@canonical.com>
>     Cc: Joe Perches <joe@perches.com>
>     [ paulmck: Skipped checking files and handled whitespace per Joe Perches. ]
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -5586,6 +5586,12 @@ sub process {
>  			}
>  		}
>  
> +# check for smp_read_barrier_depends and read_barrier_depends
> +		if (!$file && $line =~ /\b(smp_|)read_barrier_depends\s*\(/) {
> +			WARN("READ_BARRIER_DEPENDS",
> +			     "Dependency barriers should only be used in READ_ONCE or DEC Alpha code" . $herecurr);

Almost right.  Missing a '\n' after "DEC Alpha code".
Without the '\n', running checkpatch with --terse outputs badly.

If you really wanted to optimize, you could make the first (smp_|)
become (?:smp_|) to avoid the unused capture group.
Or perhaps this could emit the actual type in the message like:

		if (!$file && $line =~ /\b((?:smp_|)read_barrier_depends)\s*\(/ {
			WARN("READ_BARRIER_DEPENDS",
			     "$1 should only be used in READ_ONCE or DEC Alpha code\n" . $herecurr);

  reply	other threads:[~2017-12-02  4:45 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-01 19:50 [PATCH tip/core/rcu 0/21] De-emphasize {smp_,}read_barrier_depends Paul E. McKenney
2017-12-01 19:50 ` [PATCH tip/core/rcu 01/21] doc: READ_ONCE() now implies smp_barrier_depends() Paul E. McKenney
2017-12-01 19:50 ` [PATCH tip/core/rcu 02/21] mn10300: READ_ONCE() now implies smp_read_barrier_depends() Paul E. McKenney
2017-12-01 19:50 ` [PATCH tip/core/rcu 03/21] drivers/net/ethernet/qlogic/qed: Fix __qed_spq_block() ordering Paul E. McKenney
2017-12-01 19:50 ` [PATCH tip/core/rcu 04/21] fs/dcache: Use release-acquire for name/length update Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 05/21] percpu: READ_ONCE() now implies smp_read_barrier_depends() Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 06/21] rcu: Adjust read-side accessor comments for READ_ONCE() Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 07/21] rtnetlink: Update now-misleading smp_read_barrier_depends() comment Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 08/21] seqlock: Remove now-redundant smp_read_barrier_depends() Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 09/21] uprobes: " Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 10/21] locking: Remove smp_read_barrier_depends() from queued_spin_lock_slowpath() Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 11/21] tracepoint: Remove smp_read_barrier_depends() from comment Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 12/21] lib/assoc_array: Remove smp_read_barrier_depends() Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 13/21] mm/ksm: Remove now-redundant smp_read_barrier_depends() Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 14/21] netfilter: " Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 15/21] keyring: " Paul E. McKenney
2017-12-04  0:59   ` James Morris
2017-12-04 18:54     ` Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 16/21] drivers/infiniband: " Paul E. McKenney
2017-12-02  0:11   ` Jason Gunthorpe
2017-12-02  1:08     ` Paul E. McKenney
2017-12-05 15:08       ` Jason Gunthorpe
2017-12-05 20:06         ` Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 17/21] doc: De-emphasize smp_read_barrier_depends Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 18/21] genetlink: Remove smp_read_barrier_depends() from comment Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 19/21] netlink: " Paul E. McKenney
2017-12-01 19:51 ` [PATCH tip/core/rcu 20/21] checkpatch: Add warnings for {smp_,}read_barrier_depends() Paul E. McKenney
2017-12-01 20:14   ` Joe Perches
2017-12-01 21:44     ` Paul E. McKenney
2017-12-02  4:45       ` Joe Perches [this message]
2017-12-04 19:06         ` Paul E. McKenney
2017-12-04 19:12           ` Joe Perches
2017-12-01 19:51 ` [PATCH tip/core/rcu 21/21] drivers/vhost: Remove now-redundant read_barrier_depends() Paul E. McKenney
2017-12-05 18:31   ` Michael S. Tsirkin
2017-12-05 18:39     ` Peter Zijlstra
2017-12-05 18:57       ` Michael S. Tsirkin
2017-12-05 19:17         ` Peter Zijlstra
2017-12-05 19:24           ` Michael S. Tsirkin
2017-12-05 19:33             ` Paul E. McKenney
2017-12-05 19:51               ` Michael S. Tsirkin
2017-12-05 19:57                 ` Peter Zijlstra
2017-12-05 20:28                   ` Michael S. Tsirkin
2017-12-05 21:17                     ` Peter Zijlstra
2017-12-05 21:42                       ` Michael S. Tsirkin
2017-12-05 20:08                 ` Paul E. McKenney
2017-12-05 21:24                   ` Michael S. Tsirkin
2017-12-05 21:36                     ` Paul E. McKenney
2017-12-05 21:43                       ` Michael S. Tsirkin
2017-12-05 22:02                         ` Paul E. McKenney
2017-12-05 22:09                       ` Peter Zijlstra
2017-12-05 21:57                     ` Peter Zijlstra
2017-12-05 22:09                       ` Michael S. Tsirkin
2017-12-05 23:39                         ` Paul E. McKenney
2017-12-05 19:55             ` Peter Zijlstra
2017-12-04 15:38 ` [PATCH tip/core/rcu 01/21] doc: READ_ONCE() now implies smp_barrier_depends() David Howells
2017-12-04 18:52   ` Paul E. McKenney
2017-12-04 21:54     ` Peter Zijlstra
2017-12-04 22:15       ` Paul E. McKenney
2017-12-04 22:39     ` David Howells
2017-12-04 22:57       ` Peter Zijlstra

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