1 files changed, 23 insertions, 0 deletions

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 06578311c63f..78b1deae3fa2 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -140,6 +140,29 @@ out:
         return ret;
 }
 
+int ioprio_best(unsigned short aprio, unsigned short bprio)
+{
+        unsigned short aclass = IOPRIO_PRIO_CLASS(aprio);
+        unsigned short bclass = IOPRIO_PRIO_CLASS(bprio);
+
+        if (!ioprio_valid(aprio))
+                return bprio;
+        if (!ioprio_valid(bprio))
+                return aprio;
+
+        if (aclass == IOPRIO_CLASS_NONE)
+                aclass = IOPRIO_CLASS_BE;
+        if (bclass == IOPRIO_CLASS_NONE)
+                bclass = IOPRIO_CLASS_BE;
+
+        if (aclass == bclass)
+                return min(aprio, bprio);
+        if (aclass > bclass)
+                return bprio;
+        else
+                return aprio;
+}
+
 asmlinkage long sys_ioprio_get(int which, int who)
 {
         struct task_struct *g, *p;