From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/3] mmc: dw_mmc: add dw_mmc-k3 for k3 platform
Date: Mon, 30 Dec 2013 21:27:41 +0100 [thread overview]
Message-ID: <201312302127.41690.arnd@arndb.de> (raw)
In-Reply-To: <52C1AB34.3010402@linaro.org>
On Monday 30 December 2013, zhangfei wrote:
> >>>> +static int dw_mci_k3_suspend(struct device *dev)
> >>>> +{
> >>>> + struct dw_mci *host = dev_get_drvdata(dev);
> >>>> + int ret = 0;
> >>>> +
> >>>> + ret = dw_mci_suspend(host);
> >>>
> >>> You should never initialize local variables when they are set later in the
> >>> function (the ret = 0 part above). For more complex functions, this prevents
> >>> gcc from warning you about accidentally uninitialized uses.
>
> I am sorry I may fall into the dead end, but still quite not understand
> this rule.
> I alwayes thought it would be a good habit to init local variables before.
> Do you mean it should NOT init local variable as much as possible and
> only init on demand, like solving the gcc warning.
> Why not init the them at start in case random value cause unpredicted error?
The gcc warnings are 100% correct, we can use them as a tool to write better
code. If you write code that has no warnings with a modern compiler, you will
never use random values, but if you always initialize the local variables,
you can end up accidentally using '0' where you shouldn't have.
See http://rusty.ozlabs.org/?p=232 for an excellent article on the topic
by former Linaro assignee Rusty Russell.
Arnd
next prev parent reply other threads:[~2013-12-30 20:27 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-28 14:34 [PATCH v6 0/3] mmc: dw_mmc: add dw_mmc-k3 Zhangfei Gao
2013-12-28 14:34 ` [PATCH 1/3] mmc: dw_mmc: use slot-gpio to handle cd pin Zhangfei Gao
2013-12-28 14:34 ` [PATCH 2/3] mmc: dw_mmc: add dw_mmc-k3 for k3 platform Zhangfei Gao
2013-12-29 21:05 ` Arnd Bergmann
2013-12-29 23:55 ` Jaehoon Chung
2013-12-30 2:32 ` Zhangfei Gao
2013-12-30 17:19 ` zhangfei
2013-12-30 20:27 ` Arnd Bergmann [this message]
2013-12-31 4:43 ` zhangfei
2013-12-31 13:20 ` Gerhard Sittig
2014-01-02 2:19 ` zhangfei
2014-01-02 3:07 ` Zhangfei Gao
2013-12-28 14:34 ` [PATCH 3/3] clk: hisilicon: add hi3620_mmc_clks Zhangfei Gao
-- strict thread matches above, loose matches on Subject: below --
2014-01-09 14:35 [PATCH v7 0/3] mmc: dw_mmc: add dw_mmc-k3 Zhangfei Gao
2014-01-09 14:35 ` [PATCH 2/3] mmc: dw_mmc: add dw_mmc-k3 for k3 platform Zhangfei Gao
2014-01-09 14:45 ` Arnd Bergmann
2014-01-10 13:39 ` Seungwon Jeon
2014-01-10 14:12 ` zhangfei
2014-01-13 2:09 ` Seungwon Jeon
2014-01-13 2:37 ` zhangfei
2014-01-13 5:32 ` Seungwon Jeon
2014-01-13 8:30 ` zhangfei
2014-01-14 9:38 ` Seungwon Jeon
2014-01-14 9:47 ` zhangfei
2013-12-14 2:12 [PATCH v5 0/3] mmc: dw_mmc: add dw_mmc-k3 Zhangfei Gao
2013-12-14 2:12 ` [PATCH 2/3] mmc: dw_mmc: add dw_mmc-k3 for k3 platform Zhangfei Gao
2013-12-16 3:50 ` Seungwon Jeon
2013-12-16 5:05 ` zhangfei
2013-12-16 7:29 ` Seungwon Jeon
2013-12-16 8:08 ` zhangfei
2013-12-16 9:18 ` Seungwon Jeon
2013-12-16 11:07 ` zhangfei
2013-12-16 13:12 ` Zhangfei Gao
2013-12-20 2:31 ` zhangfei
2013-12-26 4:33 ` Jaehoon Chung
2013-12-27 6:13 ` zhangfei
2013-12-11 14:02 [PATCH v4 0/3] mmc: dw_mmc: add dw_mmc-k3 Zhangfei Gao
2013-12-11 14:02 ` [PATCH 2/3] mmc: dw_mmc: add dw_mmc-k3 for k3 platform Zhangfei Gao
2013-12-11 14:49 ` Arnd Bergmann
2013-12-11 15:36 ` zhangfei
2013-12-11 15:53 ` zhangfei
2013-12-11 20:12 ` Arnd Bergmann
2013-12-12 13:27 ` zhangfei
2013-12-12 14:13 ` Zhangfei Gao
2013-12-12 20:40 ` Arnd Bergmann
2013-12-13 2:57 ` zhangfei
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