[PATCH] arm_mpam: resctrl: Catch and propagate error from get_cpu_cacheinfo_id()

[Andre Przywara]

get_cpu_cacheinfo_id() can fail, in which case it returns a negative
error value.

Check the returned value for this error condition, before passing the
value on to other code, which would hide the negative number in some high
value in the unsigned type.

Fixes: 36528c7681b8 ("arm_mpam: resctrl: Add support for 'MB' resource")
Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
 drivers/resctrl/mpam_resctrl.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
index 9d223057953ab..a5e661eff86d7 100644
--- a/drivers/resctrl/mpam_resctrl.c
+++ b/drivers/resctrl/mpam_resctrl.c
@@ -786,7 +786,10 @@ static u32 get_mba_min(struct mpam_props *cprops)
 /* Find the L3 cache that has affinity with this CPU */
 static int find_l3_equivalent_bitmask(int cpu, cpumask_var_t tmp_cpumask)
 {
-	u32 cache_id = get_cpu_cacheinfo_id(cpu, 3);
+	int cache_id = get_cpu_cacheinfo_id(cpu, 3);
+
+	if (cache_id < 0)
+		return -ENOENT;
 
 	lockdep_assert_cpus_held();
 
-- 
2.43.0