From: tj@kernel.org (Tejun Heo)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC 3/4] lib: devres: add convenience function to remap a resource
Date: Mon, 24 Oct 2011 13:19:07 -0700 [thread overview]
Message-ID: <20111024201907.GD24914@google.com> (raw)
In-Reply-To: <20111024200933.GB6326@pengutronix.de>
On Mon, Oct 24, 2011 at 10:09:33PM +0200, Wolfram Sang wrote:
> > So, for library functions, it's nice if the function doesn't hold any
> > extra resource on error return. devres has grouping to support this.
> > You just need to wrap allocations inside a group and remove it on
> > success and release on error. ie.
> >
> > if (!devres_open_group(dev, NULL, GFP_KERNEL))
> > return NULL;
> > if (alloc_resource(0) < 0)
> > goto fail;
> > if (alloc_resource(1) < 0)
> > goto fail;
> > devres_remove_group(dev, NULL);
> > return 0;
> > fail:
> > devres_release_group(dev, NULL);
> > return 0;
>
> I am not sure I got what you mean here, but wouldn't it be easier to simply
> call devm_release_mem_region() when devm_ioremap comes back with a NULL
> pointer?
Oh, yeah, that would work too. :)
Thanks.
--
tejun
WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org>
To: unlisted-recipients:; (no To-header on input)
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, Greg KH <gregkh@suse.de>,
Grant Likely <grant.likely@secretlab.ca>
Subject: Re: [RFC 3/4] lib: devres: add convenience function to remap a resource
Date: Mon, 24 Oct 2011 13:19:07 -0700 [thread overview]
Message-ID: <20111024201907.GD24914@google.com> (raw)
In-Reply-To: <20111024200933.GB6326@pengutronix.de>
On Mon, Oct 24, 2011 at 10:09:33PM +0200, Wolfram Sang wrote:
> > So, for library functions, it's nice if the function doesn't hold any
> > extra resource on error return. devres has grouping to support this.
> > You just need to wrap allocations inside a group and remove it on
> > success and release on error. ie.
> >
> > if (!devres_open_group(dev, NULL, GFP_KERNEL))
> > return NULL;
> > if (alloc_resource(0) < 0)
> > goto fail;
> > if (alloc_resource(1) < 0)
> > goto fail;
> > devres_remove_group(dev, NULL);
> > return 0;
> > fail:
> > devres_release_group(dev, NULL);
> > return 0;
>
> I am not sure I got what you mean here, but wouldn't it be easier to simply
> call devm_release_mem_region() when devm_ioremap comes back with a NULL
> pointer?
Oh, yeah, that would work too. :)
Thanks.
--
tejun
next prev parent reply other threads:[~2011-10-24 20:19 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-24 8:42 [RFC 0/4] simplify remapping a resource for drivers Wolfram Sang
2011-10-24 8:42 ` Wolfram Sang
2011-10-24 8:42 ` [RFC 1/4] Documentation: devres: add allocation functions to list of supported calls Wolfram Sang
2011-10-24 15:25 ` Tejun Heo
2011-10-24 15:25 ` Tejun Heo
2011-10-24 8:42 ` [RFC 2/4] lib: devres: add annotations for #endif Wolfram Sang
2011-10-24 8:42 ` [RFC 3/4] lib: devres: add convenience function to remap a resource Wolfram Sang
2011-10-24 11:56 ` Grant Likely
2011-10-24 11:56 ` Grant Likely
2011-10-24 15:44 ` Tejun Heo
2011-10-24 15:44 ` Tejun Heo
2011-10-24 15:43 ` Tejun Heo
2011-10-24 15:43 ` Tejun Heo
2011-10-24 20:09 ` Wolfram Sang
2011-10-24 20:09 ` Wolfram Sang
2011-10-24 20:19 ` Tejun Heo [this message]
2011-10-24 20:19 ` Tejun Heo
2011-10-24 8:42 ` [RFC 4/4] watchdog: imx2: simplify resource allocation Wolfram Sang
2011-10-24 11:56 ` Grant Likely
2011-10-24 11:56 ` Grant Likely
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