87 lines
2.3 KiB
Diff
87 lines
2.3 KiB
Diff
Subject: fs: dcache: Use cpu_chill() in trylock loops
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Wed, 07 Mar 2012 21:00:34 +0100
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.0/patches-4.0.4-rt1.tar.xz
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Retry loops on RT might loop forever when the modifying side was
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preempted. Use cpu_chill() instead of cpu_relax() to let the system
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make progress.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: stable-rt@vger.kernel.org
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---
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fs/autofs4/autofs_i.h | 1 +
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fs/autofs4/expire.c | 2 +-
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fs/dcache.c | 5 +++--
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fs/namespace.c | 3 ++-
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4 files changed, 7 insertions(+), 4 deletions(-)
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--- a/fs/autofs4/autofs_i.h
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+++ b/fs/autofs4/autofs_i.h
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@@ -34,6 +34,7 @@
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#include <linux/sched.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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+#include <linux/delay.h>
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#include <asm/current.h>
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#include <asm/uaccess.h>
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--- a/fs/autofs4/expire.c
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+++ b/fs/autofs4/expire.c
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@@ -150,7 +150,7 @@ static struct dentry *get_next_positive_
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parent = p->d_parent;
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if (!spin_trylock(&parent->d_lock)) {
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spin_unlock(&p->d_lock);
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- cpu_relax();
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+ cpu_chill();
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goto relock;
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}
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spin_unlock(&p->d_lock);
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--- a/fs/dcache.c
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+++ b/fs/dcache.c
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@@ -19,6 +19,7 @@
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/fsnotify.h>
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+#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/hash.h>
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@@ -555,7 +556,7 @@ static struct dentry *dentry_kill(struct
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failed:
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spin_unlock(&dentry->d_lock);
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- cpu_relax();
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+ cpu_chill();
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return dentry; /* try again with same dentry */
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}
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@@ -2361,7 +2362,7 @@ void d_delete(struct dentry * dentry)
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if (dentry->d_lockref.count == 1) {
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if (!spin_trylock(&inode->i_lock)) {
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spin_unlock(&dentry->d_lock);
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- cpu_relax();
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+ cpu_chill();
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goto again;
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}
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dentry->d_flags &= ~DCACHE_CANT_MOUNT;
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--- a/fs/namespace.c
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+++ b/fs/namespace.c
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@@ -14,6 +14,7 @@
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#include <linux/mnt_namespace.h>
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#include <linux/user_namespace.h>
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#include <linux/namei.h>
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+#include <linux/delay.h>
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#include <linux/security.h>
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#include <linux/idr.h>
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#include <linux/init.h> /* init_rootfs */
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@@ -355,7 +356,7 @@ int __mnt_want_write(struct vfsmount *m)
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smp_mb();
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while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) {
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preempt_enable();
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- cpu_relax();
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+ cpu_chill();
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preempt_disable();
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}
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/*
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