Hi Julia, On Fri, Nov 6, 2015 at 5:44 PM, Julia Lawall <julia.lawall@xxxxxxx> wrote: > On Fri, 6 Nov 2015, Julian Calaby wrote: > >> Hi Linus, >> >> On Fri, Nov 6, 2015 at 11:56 AM, Linus Torvalds >> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: >> > On Thu, Nov 5, 2015 at 4:43 PM, Linus Torvalds >> > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: >> >> >> >> Not that this *matters*, but it's a bit odd to have to cast constants >> >> to perfectly regular C types. >> > >> > Looking around with "git grep", there's a few more of these. >> > >> > - btrfs seems to like "(unsigned long)-1" >> > >> > There's a few other users of that too, including more sparc uses. >> > >> > - scsi/qla seems to like "(unsigned long)<hexnumber>" >> > >> > - fmdrv_common.h seems to like "((unsigned long)1<<x)" for bitmaps >> > >> > along with a smattering of random noise all over of "(unsigned long) >> > n" where 'n' is some integer. >> > >> > Apparently people aren't as aware of the normal "ul" postfix syntax as >> > I would have expected. That said, it's a hundred-odd cases in all of >> > the kernel, so it's still fairly rare. >> >> Maybe this is something the kernel-janitors team should look at? (CC'd) > > Do you have some concrete examples of the code that is undesirable? Joe Perches produced a patch for checkpatch to check for this [1] Linus was complaining [2] about people producing constants with casts to basic C types in them. For instance: #define IOMMU_ERROR_CODE (~(unsigned long) 0) This could be replaced with #define IOMMU_ERROR_CODE (~0ul) or potentially #define IOMMU_ERROR_CODE (-1ul) It's not overly common, but it looks wrong. Thanks, Julian Calaby [1] https://lkml.org/lkml/2015/11/6/48 [2] https://lkml.org/lkml/2015/11/5/785 -- Julian Calaby Email: julian.calaby@xxxxxxxxx Profile: http://www.google.com/profiles/julian.calaby/ -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
