[PATCH] Don't need to disable interrupts for tasklist_lock

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 0fd1089..03dc4f2 100644 (file)
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -81,7 +81,12 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio)
        }
 
        ret = -ESRCH;
-       read_lock_irq(&tasklist_lock);
+       /*
+        * We want IOPRIO_WHO_PGRP/IOPRIO_WHO_USER to be "atomic",
+        * so we can't use rcu_read_lock(). See re-copy of ->ioprio
+        * in copy_process().
+        */
+       read_lock(&tasklist_lock);
        switch (which) {
                case IOPRIO_WHO_PROCESS:
                        if (!who)
@@ -124,7 +129,7 @@ free_uid:
                        ret = -EINVAL;
        }
 
-       read_unlock_irq(&tasklist_lock);
+       read_unlock(&tasklist_lock);
        return ret;
 }
 
@@ -170,7 +175,7 @@ asmlinkage long sys_ioprio_get(int which, int who)
        int ret = -ESRCH;
        int tmpio;
 
-       read_lock_irq(&tasklist_lock);
+       read_lock(&tasklist_lock);
        switch (which) {
                case IOPRIO_WHO_PROCESS:
                        if (!who)
@@ -221,7 +226,7 @@ asmlinkage long sys_ioprio_get(int which, int who)
                        ret = -EINVAL;
        }
 
-       read_unlock_irq(&tasklist_lock);
+       read_unlock(&tasklist_lock);
        return ret;
 }