Update bcachefs sources to dbe591cee299 bcachefs: Add missing smp_rmb()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 21 insertions, 0 deletions

diff --git a/libbcachefs/util.c b/libbcachefs/util.c
index bf555ae7..553de8d8 100644
--- a/libbcachefs/util.c
+++ b/libbcachefs/util.c
@@ -653,6 +653,27 @@ int bch2_bio_alloc_pages(struct bio *bio, size_t size, gfp_t gfp_mask)
 	return 0;
 }
 
+u64 bch2_get_random_u64_below(u64 ceil)
+{
+	if (ceil <= U32_MAX)
+		return __get_random_u32_below(ceil);
+
+	/* this is the same (clever) algorithm as in __get_random_u32_below() */
+	u64 rand = get_random_u64();
+	u64 mult = ceil * rand;
+
+	if (unlikely(mult < ceil)) {
+		u64 bound;
+		div64_u64_rem(-ceil, ceil, &bound);
+		while (unlikely(mult < bound)) {
+			rand = get_random_u64();
+			mult = ceil * rand;
+		}
+	}
+
+	return mul_u64_u64_shr(ceil, rand, 64);
+}
+
 void memcpy_to_bio(struct bio *dst, struct bvec_iter dst_iter, const void *src)
 {
 	struct bio_vec bv;