On 11/25/2013 11:00 AM, Russell King - ARM Linux wrote: > On Mon, Nov 25, 2013 at 09:45:18AM -0800, Dan Williams wrote: >> Regardless of whether the driver was dma_request_channel as a >> fallback, it will currently use NULL to indicate an allocation >> failure. > > At the moment, dma_request_slave_channel()'s return values are valid > pointer or NULL. I'd suggest as that's how it's been established, > that function is left alone - changing the return values in this kind > of invisible way is Really Bad(tm) because you can't check that it's > right in any future users - unless you're prepared to review every > single new user of this function for the next few years or more. > > Instead, leaving it as is and introducing a new function name with > the different return error method is the right way to do this. Uggh. So here's the history of my patch series: a) Started modifying dma_request_slave_channel() since there are very few users right now, and it seemed simple to convert them all. b) Found that some places mixed dma_request_slave_channel() and dma_request_channel(). Converting dma_request_channel()'s return value in the same way seemed prohibitive since it's much more widely used and has been around for longer. c) Rewrote patch to introduce a new function instead, since that didn't require converting any existing drivers. d) Received review feedback that I really should convert the existing function's return code. e) Started work on that using the return-value-conversion idea from Dan, which allowed the two "return value styles" to co-exist easily, since I figured that would be accepted. Now you're telling me I should do what I already did in the patch, but Dan is telling me to do the opposite:-( How do we resolve this? Is there an option both you and Dan can accept? -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
