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From: mina86@mina86.com (Michal Nazarewicz)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 0/9] Remove useless on_each_cpu return value
Date: Tue, 03 Jan 2012 15:25:49 +0100	[thread overview]
Message-ID: <op.v7iidbwz3l0zgt@mpn-glaptop> (raw)
In-Reply-To: <1325600353-10895-1-git-send-email-gilad@benyossef.com>

On Tue, 03 Jan 2012 15:19:04 +0100, Gilad Ben-Yossef <gilad@benyossef.com> wrote:
> on_each_cpu() returns as its own return value the return value of
> smp_call_function(). smp_call_function() in turn returns a hard
> coded value of zero.
>
> Some callers to on_each_cpu() waste cycles and bloat code space
> by checking the return value to on_each_cpu(), probably for
> historical reasons.
>
> This patch set refactors callers to not test on_each_cpu()
> (fixed) return value and then refactors on_each_cpu to
> return void to avoid confusing future users.
>
> In other words, this patch aims to delete 18 source code lines
> while not changing any functionality :-)
>
> I tested as best as I could the x86 changes and compiled some
> of the others, but I don't have access to all the needed hardware
> for testing. Reviewers and testers welcome!

Other then the lack of Signed-off-by in the patches, looks good to me,
even though personally I'd choose a bottom-up approach, ie. make
smp_call_function() return void and from that conclude that
on_each_cpu() can return void.  With those patches, we have a situation,
where smp_call_function() has a return value which is then lost for no
immediately apparent reason lost in on_each_cpu().

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Micha? ?mina86? Nazarewicz    (o o)
ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--

  parent reply	other threads:[~2012-01-03 14:25 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-03 14:19 [RFC PATCH 0/9] Remove useless on_each_cpu return value Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 1/9] arm: avoid using on_each_cpu hard coded ret value Gilad Ben-Yossef
2012-01-09  8:28   ` Uwe Kleine-König
2012-01-03 14:19 ` [RFC PATCH 8/9] smp: refactor on_each_cpu to void returning func Gilad Ben-Yossef
2012-01-03 14:25 ` Michal Nazarewicz [this message]
2012-01-03 16:08   ` [RFC PATCH 0/9] Remove useless on_each_cpu return value Gilad Ben-Yossef
2012-01-06 13:03 ` Peter Zijlstra
2012-01-08 16:10   ` Gilad Ben-Yossef

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