From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: "DebBarma, Tarun Kanti" <tarun.kanti@ti.com>
Cc: "felipe.balbi@nokia.com" <felipe.balbi@nokia.com>,
Ohad Ben-Cohen <ohad@wizery.com>, Kalle Valo <kalle.valo@iki.fi>,
"Pandita, Vikram" <vikram.pandita@ti.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"Quadros Roger (Nokia-MS/Helsinki)" <roger.quadros@nokia.com>,
Tony Lindgren <tony@atomide.com>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
Mark Brown <broonie@opensource.wolfsonmicro.com>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
Nicolas Pitre <nico@fluxnic.net>, San Mehat <san@google.com>,
"Chikkature Rajashekar, Madhusudhan" <madhu.cr@ti.com>,
"Coelho Luciano (Nokia-MS/Helsinki)" <Luciano.Coelho@nokia.com>,
"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
Ido Yariv <ido@wizery.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 3/8] wireless: wl1271: add platform driver to get board data
Date: Wed, 11 Aug 2010 22:21:56 +0100 [thread overview]
Message-ID: <20100811212156.GB827@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <5A47E75E594F054BAF48C5E4FC4B92AB0324110AC1@dbde02.ent.ti.com>
On Thu, Aug 12, 2010 at 12:22:54AM +0530, DebBarma, Tarun Kanti wrote:
> True; however if we go by that argument than we can also assume pdata
> is valid, so that we would not need the below check.
If pdev was ever NULL in a probe function, the kernel deserves to OOPS
so that you have a backtrace to fix the bugger.
Basically, a probe function is only called when the driver finds a
matching device to bind to - so the device _must_ already exist and
be valid. It's basically guaranteed. So checking for a NULL pdev is
not only a waste of space, it's a waste of CPU time and developer time
writing the check as well.
On the other hand, platform data passed in via a platform device _is_
liable to be NULL if whatever created the platform device didn't
set the platform data up. So we can't guarantee that the platform
data will exist. So a NULL check is appropriate here.
So, if an API in normal operation requires non-NULL data to be passed,
don't bother checking for a NULL pointer. If you're passed a NULL
pointer in this situation, you deserve to OOPS so you get a backtrace
to fix the problem rather than silently ignoring the problem.
next prev parent reply other threads:[~2010-08-11 21:23 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-11 18:21 [PATCH v4 0/8] native support for wl1271 on ZOOM Ohad Ben-Cohen
2010-08-11 18:21 ` [PATCH v4 1/8] wireless: wl1271: make wl12xx.h common to both spi and sdio Ohad Ben-Cohen
2010-08-11 18:21 ` [PATCH v4 2/8] wireless: wl1271: support return value for the set power func Ohad Ben-Cohen
2010-08-11 18:35 ` DebBarma, Tarun Kanti
2010-08-11 22:19 ` Ohad Ben-Cohen
2010-08-11 18:21 ` [PATCH v4 3/8] wireless: wl1271: add platform driver to get board data Ohad Ben-Cohen
2010-08-11 18:42 ` DebBarma, Tarun Kanti
2010-08-11 18:47 ` Felipe Balbi
2010-08-11 18:52 ` DebBarma, Tarun Kanti
2010-08-11 18:57 ` Felipe Balbi
2010-08-11 19:27 ` DebBarma, Tarun Kanti
2010-08-11 21:25 ` Russell King - ARM Linux
2010-08-11 22:15 ` Ohad Ben-Cohen
2010-08-12 6:40 ` Ohad Ben-Cohen
2010-08-12 9:55 ` Russell King - ARM Linux
2010-08-13 0:01 ` Ohad Ben-Cohen
2010-08-16 4:21 ` DebBarma, Tarun Kanti
2010-08-12 5:21 ` Felipe Balbi
2010-08-11 21:21 ` Russell King - ARM Linux [this message]
2010-08-11 20:10 ` Ohad Ben-Cohen
2010-08-11 21:34 ` Vitaly Wool
2010-08-11 22:18 ` Ohad Ben-Cohen
2010-08-12 5:27 ` Felipe Balbi
2010-08-11 18:21 ` [PATCH v4 4/8] wireless: wl1271: take irq info from private " Ohad Ben-Cohen
2010-08-11 18:21 ` [PATCH v4 5/8] wireless: wl1271: make ref_clock configurable by board Ohad Ben-Cohen
2010-08-11 18:21 ` [PATCH v4 6/8] omap: hsmmc: remove unused variable Ohad Ben-Cohen
2010-08-11 18:21 ` [PATCH v4 7/8] omap: zoom: add fixed regulator device for wlan Ohad Ben-Cohen
2010-08-11 18:21 ` [PATCH v4 8/8] omap: zoom: add mmc3/wl1271 device support Ohad Ben-Cohen
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