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author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-10-19 23:19:35 -0600 |
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committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-11-18 02:15:12 +0100 |
commit | 7f576b2593a978451416424e75f69ad1e3ae4efe (patch) | |
tree | aec27836d4be841b9aa495e2fb577b06d1f964fb /net/sched/act_sample.c | |
parent | e9a688bcb19348862afe30d7c85bc37c4c293471 (diff) | |
download | linux-next-7f576b2593a978451416424e75f69ad1e3ae4efe.tar.gz |
random: add helpers for random numbers with given floor or range
Now that we have get_random_u32_below(), it's nearly trivial to make
inline helpers to compute get_random_u32_above() and
get_random_u32_inclusive(), which will help clean up open coded loops
and manual computations throughout the tree.
One snag is that in order to make get_random_u32_inclusive() operate on
closed intervals, we have to do some (unlikely) special case handling if
get_random_u32_inclusive(0, U32_MAX) is called. The least expensive way
of doing this is actually to adjust the slowpath of
get_random_u32_below() to have its undefined 0 result just return the
output of get_random_u32(). We can make this basically free by calling
get_random_u32() before the branch, so that the branch latency gets
interleaved.
Cc: stable@vger.kernel.org # to ease future backports that use this api
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'net/sched/act_sample.c')
0 files changed, 0 insertions, 0 deletions