Messages in this thread | | | Date | Mon, 19 May 2014 16:17:12 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH 2/5] dma-mapping: Add devm_ interface for dma_map_single() |
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Hello, Eli.
On Sat, May 17, 2014 at 03:19:21PM +0300, Eli Billauer wrote: > >>+ if (dma_mapping_error(dev, dma_handle)) { > >>+ devres_free(dr); > >>+ return 0; > >Can't we just keep returning dma_handle? Even if that means invoking > >->mapping_error() twice? It's yucky to have subtly different error > >return especially because in most cases it won't fail. > Yucky it is indeed. There are however two problems with keeping the existing > API: > > * What to do if devres_alloc() fails. How do I signal back an error? The > only way I can think of is returning zero. But if the caller should know > that zero means failure, I've already broken the API. I might as well return > zero for any kind of failure.
What can't it just do the following?
if (dma_mapping_error(dev, dma_handle)) { devres_free(dr); return dma_handle; }
The caller would have to invoke dma_mapping_error() again but is that a problem?
Thanks.
-- tejun
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