From 64e9a97981b95631be1e41705c2aea9a545a7213 Mon Sep 17 00:00:00 2001
From: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
Date: Tue, 10 Mar 2020 00:54:12 +0900
Subject: [PATCH] cgroup2: fix conversion

* TestConvertCPUSharesToCgroupV2Value(0) was returning 70369281052672, while the correct value is 0
* ConvertBlkIOToCgroupV2Value(0) was returning 32, while the correct value is 0
* ConvertBlkIOToCgroupV2Value(1000) was returning 4, while the correct value is 10000

Fix #2244
Follow-up to #2212 #2213

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
---
 libcontainer/cgroups/utils.go      |  8 +++++++-
 libcontainer/cgroups/utils_test.go | 28 ++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/libcontainer/cgroups/utils.go b/libcontainer/cgroups/utils.go
index 861716e82..704941cdf 100644
--- a/libcontainer/cgroups/utils.go
+++ b/libcontainer/cgroups/utils.go
@@ -592,7 +592,10 @@ func isEINVAL(err error) bool {
 // the formula for BlkIOWeight is y = (1 + (x - 10) * 9999 / 990)
 // convert linearly from [10-1000] to [1-10000]
 func ConvertBlkIOToCgroupV2Value(blkIoWeight uint16) uint64 {
-	return uint64(1 + (blkIoWeight-10)*9999/990)
+	if blkIoWeight == 0 {
+		return 0
+	}
+	return uint64(1 + (uint64(blkIoWeight)-10)*9999/990)
 }
 
 // Since the OCI spec is designed for cgroup v1, in some cases
@@ -601,5 +604,8 @@ func ConvertBlkIOToCgroupV2Value(blkIoWeight uint16) uint64 {
 // convert from [2-262144] to [1-10000]
 // 262144 comes from Linux kernel definition "#define MAX_SHARES (1UL << 18)"
 func ConvertCPUSharesToCgroupV2Value(cpuShares uint64) uint64 {
+	if cpuShares == 0 {
+		return 0
+	}
 	return (1 + ((cpuShares-2)*9999)/262142)
 }
diff --git a/libcontainer/cgroups/utils_test.go b/libcontainer/cgroups/utils_test.go
index 3214b9de0..3dfa6a0d4 100644
--- a/libcontainer/cgroups/utils_test.go
+++ b/libcontainer/cgroups/utils_test.go
@@ -457,3 +457,31 @@ func TestGetHugePageSizeImpl(t *testing.T) {
 		}
 	}
 }
+
+func TestConvertBlkIOToCgroupV2Value(t *testing.T) {
+	cases := map[uint16]uint64{
+		0:    0,
+		10:   1,
+		1000: 10000,
+	}
+	for i, expected := range cases {
+		got := ConvertBlkIOToCgroupV2Value(i)
+		if got != expected {
+			t.Errorf("expected ConvertBlkIOToCgroupV2Value(%d) to be %d, got %d", i, expected, got)
+		}
+	}
+}
+
+func TestConvertCPUSharesToCgroupV2Value(t *testing.T) {
+	cases := map[uint64]uint64{
+		0:      0,
+		2:      1,
+		262144: 10000,
+	}
+	for i, expected := range cases {
+		got := ConvertCPUSharesToCgroupV2Value(i)
+		if got != expected {
+			t.Errorf("expected ConvertCPUSharesToCgroupV2Value(%d) to be %d, got %d", i, expected, got)
+		}
+	}
+}