Messages in this thread | | | Date | Mon, 24 Oct 2011 08:43:07 -0700 | From | Tejun Heo <> | Subject | Re: [RFC 3/4] lib: devres: add convenience function to remap a resource |
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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
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