From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 11/31] dma: add channel request API that supports deferred probe Date: Mon, 18 Nov 2013 10:42:08 -0700 Message-ID: <528A5170.3090809@wwwdotorg.org> References: <1384548866-13141-1-git-send-email-swarren@wwwdotorg.org> <1384548866-13141-12-git-send-email-swarren@wwwdotorg.org> <1384766276.14845.155.camel@smile> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1384766276.14845.155.camel@smile> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Shevchenko, Andriy" , "Williams, Dan J" Cc: Stephen Warren , "treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org" , "pdeschrijver-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org" , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "Koul, Vinod" List-Id: linux-tegra@vger.kernel.org On 11/18/2013 02:18 AM, Shevchenko, Andriy wrote: > On Fri, 2013-11-15 at 13:01 -0800, Dan Williams wrote: >> On Fri, Nov 15, 2013 at 12:54 PM, Stephen Warren wrote: > >>> Eventually, all drivers should be converted to this new API, the old API >>> removed, and the new API renamed to the more desirable name. > > I really would like to see more sensible and shorter names for the API > functions. I'm not sure if you're suggesting that you: a) Really want to API renaming I mention above to happen at some time. b) We need to pick a better name now, for the new API this patch introduces. If so, do you have any better suggestion? >>> --- a/drivers/dma/acpi-dma.c >>> +++ b/drivers/dma/acpi-dma.c >>> @@ -334,7 +334,7 @@ static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data) >>> * @dev: struct device to get DMA request from >>> * @index: index of FixedDMA descriptor for @dev >>> * >>> - * Returns pointer to appropriate dma channel on success or NULL on error. >>> + * Returns pointer to appropriate dma channel on success or an error pointer. >>> */ >>> struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev, >>> size_t index) >>> @@ -349,10 +349,10 @@ struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev, > > We use default value of chan if it's not found. Perhaps you have to > change it as well to something like ERR_PTR(-ENOENT). Ah yes. I think I'll keep the default value of chan = NULL, and just change the return statement to something like: return chan ? chan : ERR_PTR(-ENOENT); That way, the fact that adma->acpi_dma_xlate() returns NULL-or-valid-pointer and the check of chan against NULL inside the list_for_each_entry() won't have to change.