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authorThomas Gleixner <tglx@linutronix.de>2012-03-07 21:00:34 +0100
committerClark Williams <williams@redhat.com>2012-04-04 09:14:59 -0500
commitabd5ca54f2008c5fffb70a23a9078f4d0b61a2d4 (patch)
tree875861986700d2b891155580cc69397c9f9818bb
parent8043a0ec8ccbdb4d0e029228b4e8448061cb9529 (diff)
fs: dcache: Use cpu_chill() in trylock loops
Retry loops on RT might loop forever when the modifying side was preempted. Use cpu_chill() instead of cpu_relax() to let the system make progress. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
-rw-r--r--fs/autofs4/autofs_i.h1
-rw-r--r--fs/autofs4/expire.c2
-rw-r--r--fs/dcache.c7
-rw-r--r--fs/namespace.c3
4 files changed, 8 insertions, 5 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 308a98bdb5f7..67ed18635597 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -34,6 +34,7 @@
#include <linux/sched.h>
#include <linux/mount.h>
#include <linux/namei.h>
+#include <linux/delay.h>
#include <asm/current.h>
#include <asm/uaccess.h>
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 450f529a4eae..43afbb02856e 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -170,7 +170,7 @@ again:
parent = p->d_parent;
if (!spin_trylock(&parent->d_lock)) {
spin_unlock(&p->d_lock);
- cpu_relax();
+ cpu_chill();
goto relock;
}
spin_unlock(&p->d_lock);
diff --git a/fs/dcache.c b/fs/dcache.c
index f7908aef484a..83e8ecda6384 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -37,6 +37,7 @@
#include <linux/rculist_bl.h>
#include <linux/prefetch.h>
#include <linux/ratelimit.h>
+#include <linux/delay.h>
#include "internal.h"
/*
@@ -410,7 +411,7 @@ static inline struct dentry *dentry_kill(struct dentry *dentry, int ref)
if (inode && !spin_trylock(&inode->i_lock)) {
relock:
spin_unlock(&dentry->d_lock);
- cpu_relax();
+ cpu_chill();
return dentry; /* try again with same dentry */
}
if (IS_ROOT(dentry))
@@ -796,7 +797,7 @@ relock:
if (!spin_trylock(&dentry->d_lock)) {
spin_unlock(&dcache_lru_lock);
- cpu_relax();
+ cpu_chill();
goto relock;
}
@@ -1975,7 +1976,7 @@ again:
if (dentry->d_count == 1) {
if (inode && !spin_trylock(&inode->i_lock)) {
spin_unlock(&dentry->d_lock);
- cpu_relax();
+ cpu_chill();
goto again;
}
dentry->d_flags &= ~DCACHE_CANT_MOUNT;
diff --git a/fs/namespace.c b/fs/namespace.c
index 63fd6d78be27..311264b1002d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -31,6 +31,7 @@
#include <linux/idr.h>
#include <linux/fs_struct.h>
#include <linux/fsnotify.h>
+#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "pnode.h"
@@ -346,7 +347,7 @@ int mnt_want_write(struct vfsmount *mnt)
*/
while (mnt->mnt_flags & MNT_WRITE_HOLD) {
preempt_enable();
- cpu_relax();
+ cpu_chill();
preempt_disable();
}
/*