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netem: remove unnecessary 64 bit modulus

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Fix compilation on 32 bit platforms (where doing modulus operation
with 64 bit requires extra glibc functions) by truncation.
The jitter for table distribution is limited to a 32 bit value
because random numbers are scaled as 32 bit value.

Also fix some whitespace.

Fixes: 99803171ef ("netem: add uapi to express delay and jitter in nanoseconds")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stephen Hemminger 2017-11-14 11:27:02 -08:00 committed by David S. Miller
parent bce552fd6f
commit 9b0ed89172
1 changed files with 3 additions and 3 deletions
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6
net/sched/sch_netem.c
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@ -312,9 +312,9 @@ static bool loss_event(struct netem_sched_data *q)
* std deviation sigma. Uses table lookup to approximate the desired
* distribution, and a uniformly-distributed pseudo-random source.
*/
static s64 tabledist(s64 mu, s64 sigma,
static s64 tabledist(s64 mu, s32 sigma,
struct crndstate *state,
const struct disttable *dist)
const struct disttable *dist)
{
s64 x;
long t;
@ -327,7 +327,7 @@ static s64 tabledist(s64 mu, s64 sigma,
/* default uniform distribution */
if (dist == NULL)
return (rnd % (2*sigma)) - sigma + mu;
return (rnd % (2 * sigma)) - sigma + mu;
t = dist->table[rnd % dist->size];
x = (sigma % NETEM_DIST_SCALE) * t;