On Sat, 7 Nov 2015, Julian Calaby wrote: > 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. The checkpatch solution indeed looks fine in this case. julia > 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 > -- 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
