linuxkit/kernel/patches-4.14.x-rt/0278-fs-namespace-preemption-fix.patch
Tiejun Chen a1d47ff766 update -rt to 4.14.53-rt34
Signed-off-by: Tiejun Chen <tiejun.china@gmail.com>
2018-07-06 14:02:07 +08:00

36 lines
1.1 KiB
Diff

From a45c65024ac8f55ad0dc1ccfa72803fb57500595 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 19 Jul 2009 08:44:27 -0500
Subject: [PATCH 278/418] fs: namespace preemption fix
On RT we cannot loop with preemption disabled here as
mnt_make_readonly() might have been preempted. We can safely enable
preemption while waiting for MNT_WRITE_HOLD to be cleared. Safe on !RT
as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
fs/namespace.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 1eb3bfd8be5a..0a74d6c02928 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -353,8 +353,11 @@ int __mnt_want_write(struct vfsmount *m)
* incremented count after it has set MNT_WRITE_HOLD.
*/
smp_mb();
- while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD)
+ while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) {
+ preempt_enable();
cpu_relax();
+ preempt_disable();
+ }
/*
* After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
* be set to match its requirements. So we must not load that until
--
2.17.1