Messages in this thread | | | Subject | Re: [Intel PMC TGPIO Driver 1/5] drivers/ptp: Add Enhanced handling of reserve fields | From | Jacob Keller <> | Date | Fri, 31 Jan 2020 08:54:19 -0800 |
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On 12/11/2019 1:48 PM, christopher.s.hall@intel.com wrote: > From: Christopher Hall <christopher.s.hall@intel.com> > > Add functions that parameterize checking and zeroing of reserve fields in > ioctl arguments. Eliminates need to change this code when repurposing > reserve fields. >
Nice!
> Signed-off-by: Christopher Hall <christopher.s.hall@intel.com> > --- > drivers/ptp/ptp_chardev.c | 60 +++++++++++++++++++++------------------ > 1 file changed, 33 insertions(+), 27 deletions(-) > > diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c > index 9d72ab593f13..f9ad6df57fa5 100644 > --- a/drivers/ptp/ptp_chardev.c > +++ b/drivers/ptp/ptp_chardev.c > @@ -12,6 +12,7 @@ > #include <linux/timekeeping.h> > > #include <linux/nospec.h> > +#include <linux/string.h> > > #include "ptp_private.h" > > @@ -106,6 +107,28 @@ int ptp_open(struct posix_clock *pc, fmode_t fmode) > return 0; > } > > +/* Returns -1 if any reserved fields are non-zero */ > +static inline int _check_rsv_field(unsigned int *field, size_t size) > +{ > + unsigned int *iter; > + int ret = 0; > + > + for (iter = field; iter < field+size && ret == 0; ++iter) > + ret = *iter == 0 ? 0 : -1; > + > + return ret; > +} > +#define check_rsv_field(field) _check_rsv_field(field, ARRAY_SIZE(field)) > +
This assumes that reserved fields will always be arrays. Seems like a reasonable restriction to me.
Are the reserved fields always integers? Seems so. Ok.
> +static inline void _zero_rsv_field(unsigned int *field, size_t size) > +{ > + unsigned int *iter; > + > + for (iter = field; iter < field+size; ++iter) > + *iter = 0; > +} > +#define zero_rsv_field(field) _zero_rsv_field(field, ARRAY_SIZE(field)) > + > long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) > { > struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); > @@ -154,7 +177,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) > req.extts.flags |= PTP_STRICT_FLAGS; > /* Make sure no reserved bit is set. */ > if ((req.extts.flags & ~PTP_EXTTS_VALID_FLAGS) || > - req.extts.rsv[0] || req.extts.rsv[1]) { > + check_rsv_field(req.extts.rsv)) { > err = -EINVAL; > break; > } > @@ -166,8 +189,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) > } > } else if (cmd == PTP_EXTTS_REQUEST) { > req.extts.flags &= PTP_EXTTS_V1_VALID_FLAGS; > - req.extts.rsv[0] = 0; > - req.extts.rsv[1] = 0; > + zero_rsv_field(req.extts.rsv); > } > if (req.extts.index >= ops->n_ext_ts) { > err = -EINVAL; > @@ -188,17 +210,13 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) > break; > } > if (((req.perout.flags & ~PTP_PEROUT_VALID_FLAGS) || > - req.perout.rsv[0] || req.perout.rsv[1] || > - req.perout.rsv[2] || req.perout.rsv[3]) && > - cmd == PTP_PEROUT_REQUEST2) { > + check_rsv_field(req.perout.rsv)) && > + cmd == PTP_PEROUT_REQUEST2) { > err = -EINVAL; > break; > } else if (cmd == PTP_PEROUT_REQUEST) { > req.perout.flags &= PTP_PEROUT_V1_VALID_FLAGS; > - req.perout.rsv[0] = 0; > - req.perout.rsv[1] = 0; > - req.perout.rsv[2] = 0; > - req.perout.rsv[3] = 0; > + zero_rsv_field(req.perout.rsv); > } > if (req.perout.index >= ops->n_per_out) { > err = -EINVAL; > @@ -258,7 +276,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) > break; > } > if (extoff->n_samples > PTP_MAX_SAMPLES > - || extoff->rsv[0] || extoff->rsv[1] || extoff->rsv[2]) { > + || check_rsv_field(extoff->rsv)) { > err = -EINVAL; > break; > } > @@ -318,17 +336,11 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) > err = -EFAULT; > break; > } > - if ((pd.rsv[0] || pd.rsv[1] || pd.rsv[2] > - || pd.rsv[3] || pd.rsv[4]) > - && cmd == PTP_PIN_GETFUNC2) { > + if (check_rsv_field(pd.rsv) && cmd == PTP_PIN_GETFUNC2) {
Not that it's a big deal, but I think this might read more clearly if this was "cmd == PTP_PIN_GETFUNC2 && check_rsv_field(pd.rsv)"
Thanks, Jake
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