Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH 03/12] net: igb: avoid using timespec | Date | Thu, 01 Oct 2015 22:01:57 +0200 |
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On Thursday 01 October 2015 21:17:45 Richard Cochran wrote: > On Wed, Sep 30, 2015 at 01:26:33PM +0200, Arnd Bergmann wrote: > > diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c > > index 5982f28d521a..c44df87c38de 100644 > > --- a/drivers/net/ethernet/intel/igb/igb_ptp.c > > +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c > > @@ -143,7 +143,7 @@ static void igb_ptp_write_i210(struct igb_adapter *adapter, > > * sub-nanosecond resolution. > > */ > > wr32(E1000_SYSTIML, ts->tv_nsec); > > - wr32(E1000_SYSTIMH, ts->tv_sec); > > + wr32(E1000_SYSTIMH, (u32)ts->tv_sec); > > This cast is unnecessary, because wr32 is writel, and that parameter > is a u32.
I tried to use this pattern whenever I convert the 64-bit 'long long' tv_sec member of 'struct timespec64' into a 32-bit number, to annotate the loss of range.
I have thought about defining separate helpers like this
/* result will overflow in 2038 for real time */ static inline s32 time64_to_s32_y2038(time64_t time) { return time; }
/* result will overflow in 2106 for real time */ static inline u32 time64_to_u32_y2106(time64_t time) { return time; }
/* monotonic times can safely be represented as 32 bit */ static inline s32 time64_to_s32_monotonic(time64_t time) { return time; }
This would make it even more explicit, but my fear was that I was adding too much complexity like that.
Arnd
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