From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Tue, 29 Aug 2006 07:17:41 +0000 (+0200)
Subject: [PATCH] Don't need to disable interrupts for tasklist_lock
X-Git-Tag: v2.6.19-rc1~640^2~25
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cf342e52e3117391868fb4bd900ce772a27a5a1a;p=linux-2.6

[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 0fd1089d7b..03dc4f269b 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;
 }