1 files changed, 28 insertions, 2 deletions

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 93aa5715f224..78b1deae3fa2 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -44,6 +44,9 @@ static int set_task_ioprio(struct task_struct *task, int ioprio)
         task->ioprio = ioprio;
 
         ioc = task->io_context;
+        /* see wmb() in current_io_context() */
+        smp_read_barrier_depends();
+
         if (ioc && ioc->set_ioprio)
                 ioc->set_ioprio(ioc, ioprio);
 
@@ -111,9 +114,9 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
                                         continue;
                                 ret = set_task_ioprio(p, ioprio);
                                 if (ret)
-                                        break;
+                                        goto free_uid;
                         } while_each_thread(g, p);
-
+free_uid:
                         if (who)
                                 free_uid(user);
                         break;
@@ -137,6 +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;