2020-03-28 16:43:49

by George Spelvin

[permalink] [raw]
Subject: [RFC PATCH v1 12/50] Treewide: Extirpate prandom_u32_state(rnd) % range

There's no prandom_u32_state_max, so we're using reciprocal_scale()
here directly.

(Also add a missing "const" to drivers/gpu/drm/i915/selftests/scatterist.c)

Signed-off-by: George Spelvin <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: [email protected]
Cc: Davidlohr Bueso <[email protected]>
Cc: Chris Wilson <[email protected]>
---
drivers/gpu/drm/i915/selftests/scatterlist.c | 4 ++--
lib/interval_tree_test.c | 7 ++++---
2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/selftests/scatterlist.c b/drivers/gpu/drm/i915/selftests/scatterlist.c
index d599186d5b714..be9ff9d03eada 100644
--- a/drivers/gpu/drm/i915/selftests/scatterlist.c
+++ b/drivers/gpu/drm/i915/selftests/scatterlist.c
@@ -195,13 +195,13 @@ static unsigned int random_page_size_pages(unsigned long n,
struct rnd_state *rnd)
{
/* 4K, 64K, 2M */
- static unsigned int page_count[] = {
+ static const unsigned int page_count[] = {
BIT(12) >> PAGE_SHIFT,
BIT(16) >> PAGE_SHIFT,
BIT(21) >> PAGE_SHIFT,
};

- return page_count[(prandom_u32_state(rnd) % 3)];
+ return page_count[reciprocal_scale(prandom_u32_state(rnd), 3)];
}

static inline bool page_contiguous(struct page *first,
diff --git a/lib/interval_tree_test.c b/lib/interval_tree_test.c
index f37f4d44faa90..8c129c8c638b9 100644
--- a/lib/interval_tree_test.c
+++ b/lib/interval_tree_test.c
@@ -43,8 +43,8 @@ static void init(void)
int i;

for (i = 0; i < nnodes; i++) {
- u32 b = (prandom_u32_state(&rnd) >> 4) % max_endpoint;
- u32 a = (prandom_u32_state(&rnd) >> 4) % b;
+ u32 b = reciprocal_scale(prandom_u32_state(&rnd), max_endpoint);
+ u32 a = reciprocal_scale(prandom_u32_state(&rnd), b);

nodes[i].start = a;
nodes[i].last = b;
@@ -56,7 +56,8 @@ static void init(void)
* which is pointless.
*/
for (i = 0; i < nsearches; i++)
- queries[i] = (prandom_u32_state(&rnd) >> 4) % max_endpoint;
+ queries[i] = reciprocal_scale(prandom_u32_state(&rnd),
+ max_endpoint);
}

static int interval_tree_test_init(void)
--
2.26.0