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-rw-r--r--net/ceph/crush/mapper.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/net/ceph/crush/mapper.c b/net/ceph/crush/mapper.c
index 5fcfb98f309e..511ade95339a 100644
--- a/net/ceph/crush/mapper.c
+++ b/net/ceph/crush/mapper.c
@@ -253,9 +253,15 @@ static __u64 crush_ln(unsigned int xin)
/* normalize input */
iexpon = 15;
- while (!(x & 0x18000)) {
- x <<= 1;
- iexpon--;
+
+ /*
+ * figure out number of bits we need to shift and
+ * do it in one step instead of iteratively
+ */
+ if (!(x & 0x18000)) {
+ int bits = __builtin_clz(x & 0x1FFFF) - 16;
+ x <<= bits;
+ iexpon = 15 - bits;
}
index1 = (x >> 8) << 1;