From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932898Ab1JXPnO (ORCPT ); Mon, 24 Oct 2011 11:43:14 -0400 Received: from mail-qw0-f46.google.com ([209.85.216.46]:55263 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932764Ab1JXPnN (ORCPT ); Mon, 24 Oct 2011 11:43:13 -0400 Date: Mon, 24 Oct 2011 08:43:07 -0700 From: Tejun Heo To: Wolfram Sang Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Greg KH , Grant Likely Subject: Re: [RFC 3/4] lib: devres: add convenience function to remap a resource Message-ID: <20111024154307.GB24914@google.com> References: <1319445729-14841-1-git-send-email-w.sang@pengutronix.de> <1319445729-14841-4-git-send-email-w.sang@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1319445729-14841-4-git-send-email-w.sang@pengutronix.de> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Mon, Oct 24, 2011 at 10:42:08AM +0200, Wolfram Sang wrote: > * the new function is not named 'devm_ioremap_resource' because it does more than > just ioremap, namely request_mem_region. I didn't want to create implicit > knowledge here. Maybe devm_request_and_ioremap_resource()? Maybe it's a bit long but A_to_B names are usually used for trivial conversions. > +int __must_check devm_resource_to_mapped_ptr(struct device *dev, > + struct resource *res, void __iomem **dest) If we're already printing out dev_err(), I think we can live with %NULL return on error. > +{ > + resource_size_t size; > + const char *name; > + > + BUG_ON(!dev || !dest); > + > + *dest = NULL; > + > + if (!res || resource_type(res) != IORESOURCE_MEM) { > + dev_err(dev, "invalid resource\n"); > + return -ENOENT; > + } > + > + size = resource_size(res); > + name = res->name ?: dev_name(dev); > + > + if (!devm_request_mem_region(dev, res->start, size, name)) { > + dev_err(dev, "can't request region for resource %pR\n", res); > + return -EBUSY; > + } > + > + if (res->flags & IORESOURCE_CACHEABLE) > + *dest = devm_ioremap(dev, res->start, size); > + else > + *dest = devm_ioremap_nocache(dev, res->start, size); > + > + if (!*dest) { > + dev_err(dev, "ioremap failed for resource %pR\n", res); > + return -ENOMEM; > + } 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; Thanks. -- tejun