On 05/10/2013 02:16 AM, Wolfram Sang wrote: > devm_ioremap_resource does sanity checks on the given resource. No need to > duplicate this in the driver. > diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > - if (!res) { > - dev_err(&pdev->dev, "No mem resource for DMA\n"); > - return -EINVAL; > - } > - > tdma->base_addr = devm_ioremap_resource(&pdev->dev, res); One issue here is that it's not obvious just from reading the code that's left behind that the "missing" error-checking of the platform_get_resource() return value is OK because devm_ioremap_resource() will check it "for us". Everyone now has to mentally maintain a list of exceptions where it's OK not to error-check. A similar situation exists for e.g. kzalloc already spewing an error when allocations fail, and so drivers don't need to print a diagnostic in that case, but it's helpful if they do in most other cases, but that's another issue. Would it be better to introduce a new devm_ioremap_pdev_resource(pdev, index) that replaced both those two API calls with a single one. That way, only the author/reader of the new devm_ioremap_pdev_resource() would have to remember that caveat, and a single comment could be added so people unfamiliar with the code remember, without duplicating the comment in every driver. -- 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