[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>

1 files changed, 9 insertions, 4 deletions

diff --git a/fs/ioprio.c b/fs/ioprio.c
index 0fd1089d7bf6..03dc4f269b76 100644
--- 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;
 }