time: ntp: make 64-bit constants more robust

Impact: cleanup, no functionality changed

 - make PPM_SCALE an explicit s64 constant, to
   remove (s64) casts from usage sites.

kernel/time/ntp.o:

   text	   data	    bss	    dec	    hex	filename
   2536	    114	    136	   2786	    ae2	ntp.o.before
   2536	    114	    136	   2786	    ae2	ntp.o.after

md5:
   40a7728d1188aa18e83e21a81fa7b150  ntp.o.before.asm
   40a7728d1188aa18e83e21a81fa7b150  ntp.o.after.asm

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/linux/timex.h b/include/linux/timex.h
index 998a55d..aa3475f 100644 (file)
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -190,7 +190,7 @@ struct timex {
  * offset and maximum frequency tolerance.
  */
 #define SHIFT_USEC 16          /* frequency offset scale (shift) */
-#define PPM_SCALE (NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
+#define PPM_SCALE ((s64)NSEC_PER_USEC << (NTP_SCALE_SHIFT - SHIFT_USEC))
 #define PPM_SCALE_INV_SHIFT 19
 #define PPM_SCALE_INV ((1ll << (PPM_SCALE_INV_SHIFT + NTP_SCALE_SHIFT)) / \
                       PPM_SCALE + 1)

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 4346ed6..7447d57 100644 (file)
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -408,7 +408,7 @@ static inline void process_adjtimex_modes(struct timex *txc, struct timespec *ts
                time_status &= ~STA_NANO;
 
        if (txc->modes & ADJ_FREQUENCY) {
-               time_freq = (s64)txc->freq * PPM_SCALE;
+               time_freq = txc->freq * PPM_SCALE;
                time_freq = min(time_freq, MAXFREQ_SCALED);
                time_freq = max(time_freq, -MAXFREQ_SCALED);
        }
@@ -505,7 +505,7 @@ int do_adjtimex(struct timex *txc)
                result = TIME_ERROR;
 
        txc->freq          = shift_right((time_freq >> PPM_SCALE_INV_SHIFT) *
-                                        (s64)PPM_SCALE_INV, NTP_SCALE_SHIFT);
+                                        PPM_SCALE_INV, NTP_SCALE_SHIFT);
        txc->maxerror      = time_maxerror;
        txc->esterror      = time_esterror;
        txc->status        = time_status;