Messages in this thread | | | Date | Fri, 30 Jun 2023 15:29:50 +0200 | Subject | Re: [PATCH 2/2] include/uapi pps.h: drop not needed PPS_MAX_SOURCES define | From | Rodolfo Giometti <> |
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On 30/06/23 14:53, Greg Kroah-Hartman wrote: > On Fri, Jun 30, 2023 at 09:50:33AM +0200, Rodolfo Giometti wrote: >> On 30/06/23 09:31, Greg Kroah-Hartman wrote: >>> On Fri, Jun 30, 2023 at 09:18:26AM +0200, Rodolfo Giometti wrote: >>>> Userspace PPS clients should not known about how many PPS sources can >>>> be defined within the system (nor the rfc2783 say so), so we can >>>> safely drop this define since is not used anymore in the kernel too. >>>> >>>> Signed-off-by: Rodolfo Giometti <giometti@enneenne.com> >>>> --- >>>> drivers/pps/pps.c | 6 +++--- >>>> include/uapi/linux/pps.h | 1 - >>>> 2 files changed, 3 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c >>>> index 5d19baae6a38..1a6131608036 100644 >>>> --- a/drivers/pps/pps.c >>>> +++ b/drivers/pps/pps.c >>>> @@ -354,7 +354,7 @@ int pps_register_cdev(struct pps_device *pps) >>>> * Get new ID for the new PPS source. After idr_alloc() calling >>>> * the new source will be freely available into the kernel. >>>> */ >>>> - err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL); >>>> + err = idr_alloc(&pps_idr, pps, 0, MINORMASK, GFP_KERNEL); >>>> if (err < 0) { >>>> if (err == -ENOSPC) { >>>> pr_err("%s: too many PPS sources in the system\n", >>>> @@ -449,7 +449,7 @@ EXPORT_SYMBOL(pps_lookup_dev); >>>> static void __exit pps_exit(void) >>>> { >>>> class_destroy(pps_class); >>>> - unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES); >>>> + unregister_chrdev_region(pps_devt, MINORMASK); >>>> } >>>> static int __init pps_init(void) >>>> @@ -463,7 +463,7 @@ static int __init pps_init(void) >>>> } >>>> pps_class->dev_groups = pps_groups; >>>> - err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps"); >>>> + err = alloc_chrdev_region(&pps_devt, 0, MINORMASK, "pps"); >>>> if (err < 0) { >>>> pr_err("failed to allocate char device region\n"); >>>> goto remove_class; >>>> diff --git a/include/uapi/linux/pps.h b/include/uapi/linux/pps.h >>>> index 90f2e86020ba..8a4096f18af1 100644 >>>> --- a/include/uapi/linux/pps.h >>>> +++ b/include/uapi/linux/pps.h >>>> @@ -26,7 +26,6 @@ >>>> #include <linux/types.h> >>>> #define PPS_VERSION "5.3.6" >>>> -#define PPS_MAX_SOURCES MINORMASK >>> >>> Why change this in patch 1, and then delete this here? >>> >>> That makes no sense. >> >> I did it in two steps to be clear that the first step is about a better >> redefinition of the PPS_MAX_SOURCES define, while the second step is about >> the fact it's now that define is useless. > > Better to just convert everything in patch one, and then in patch 2 > delete the .h #define. That way, when userspace breaks, you can revert > just the last patch :)
I'm puzzled since I did as you say... patch 1/2 increases PPS_MAX_SOURCES value while patch 2/2 drops PPS_MAX_SOURCES define.
>>> And if this is exported to userspace, removing it should break things, >>> right? If not, why was it there in the first place? >> >> In reality such define is not stated within the PPS RFC2783, so userspace >> programs whose relies on such define are broken. > > RFC's do not document Linux kernel apis.
It's true, but well written PPS clients should relay only on PPS API which in turn doesn't states that define. :P
> So if any userspace code breaks, you have to put this back, sorry.
If you think that patch 2 is not good, no problem, just drop it, but please just consider applying patch 1, since increasing PPS_MAX_SOURCES value is good.
Ciao,
Rodolfo
-- GNU/Linux Solutions e-mail: giometti@enneenne.com Linux Device Driver giometti@linux.it Embedded Systems phone: +39 349 2432127 UNIX programming skype: rodolfo.giometti
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