From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: walter harms <wharms@bfs.de>
Cc: Julia Lawall <julia@diku.dk>, Vasiliy Kulikov <segooon@gmail.com>,
Ryan Mallon <ryan@bluewatersys.com>,
kernel-janitors@vger.kernel.org,
Nicolas Ferre <nicolas.ferre@atmel.com>,
Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>,
Andrew Victor <linux@maxim.org.za>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] arch/arm/mach-at91/clock.c: Add missing IS_ERR test
Date: Tue, 25 Jan 2011 10:43:33 +0000 [thread overview]
Message-ID: <20110125104333.GE11507@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <4D3EA6EC.5050305@bfs.de>
On Tue, Jan 25, 2011 at 11:33:16AM +0100, walter harms wrote:
> Would it be more easy to return NULL in the error case of clk_get() instead
> of ERR_PTR(-ENOENT) ?
>
> So the default could be return NULL and an architecture depending solution
> replacing that.
That's not how the API is defined. The API defines error-pointers to be
errors, everything should be considered valid. Please don't go down the
route of doing something architecturally different from that.
What if, say, you couldn't return the struct clk because maybe it could
only be controlled by one user? Returning an EBUSY error pointer would
indicate this condition. What if the module providing the struct clk
hasn't finished initializing - that's another reason for EBUSY rather
than ENOENT.
Error codes are useful to describe why something failed. NULL pointers
can't do that.
next prev parent reply other threads:[~2011-01-25 10:44 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-24 19:55 [PATCH 0/4] Add missing IS_ERR test Julia Lawall
2011-01-24 19:55 ` [PATCH 1/4] fs/btrfs/inode.c: " Julia Lawall
2011-01-24 19:55 ` [PATCH 2/4] arch/arm/mach-at91/clock.c: " Julia Lawall
2011-01-24 19:56 ` Ryan Mallon
2011-01-24 20:00 ` Julia Lawall
2011-01-24 20:05 ` Vasiliy Kulikov
2011-01-24 20:09 ` Julia Lawall
2011-01-24 20:14 ` Vasiliy Kulikov
2011-01-25 10:33 ` walter harms
2011-01-25 10:43 ` Russell King - ARM Linux [this message]
2011-01-25 11:12 ` walter harms
2011-01-25 11:17 ` Russell King - ARM Linux
2011-01-25 11:18 ` Julia Lawall
2011-01-25 11:26 ` Russell King - ARM Linux
2011-01-25 11:31 ` Julia Lawall
2011-01-24 20:11 ` Ryan Mallon
2011-01-24 20:28 ` Julia Lawall
2011-01-24 20:38 ` Ryan Mallon
2011-01-24 21:01 ` Julia Lawall
2011-01-24 21:06 ` Ryan Mallon
2011-01-24 21:31 ` Julia Lawall
2011-01-24 21:51 ` Ryan Mallon
2011-01-24 23:23 ` Russell King - ARM Linux
2011-01-25 1:44 ` Jean-Christophe PLAGNIOL-VILLARD
2011-01-25 6:12 ` Julia Lawall
2011-01-25 17:23 ` Jean-Christophe PLAGNIOL-VILLARD
2011-01-24 19:55 ` [PATCH 3/4] drivers/video/bf537-lq035.c: " Julia Lawall
2011-01-24 20:43 ` Mike Frysinger
2011-01-25 6:12 ` Paul Mundt
2011-01-25 8:36 ` Hennerich, Michael
2011-01-24 19:55 ` [PATCH 4/4] arch/arm/mach-omap2/smartreflex.c: " Julia Lawall
2011-01-24 21:24 ` Kevin Hilman
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