lkml.org 
[lkml]   [2012]   [Mar]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 4/5] fs: fs_struct use seqlock
Replace the open coded seqlock with a real one.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
fs/exec.c | 4 ++--
fs/fhandle.c | 4 ++--
fs/fs_struct.c | 46 ++++++++++++++++++----------------------------
fs/namei.c | 14 +++++++-------
include/linux/fs_struct.h | 16 +++++++---------
kernel/fork.c | 10 +++++-----
6 files changed, 41 insertions(+), 53 deletions(-)
Index: tip/fs/exec.c
===================================================================
--- tip.orig/fs/exec.c
+++ tip/fs/exec.c
@@ -1244,7 +1244,7 @@ static int check_unsafe_exec(struct linu
}

n_fs = 1;
- spin_lock(&p->fs->lock);
+ seq_spin_lock(&p->fs->lock);
rcu_read_lock();
for (t = next_thread(p); t != p; t = next_thread(t)) {
if (t->fs == p->fs)
@@ -1261,7 +1261,7 @@ static int check_unsafe_exec(struct linu
res = 1;
}
}
- spin_unlock(&p->fs->lock);
+ seq_spin_unlock(&p->fs->lock);

return res;
}
Index: tip/fs/fhandle.c
===================================================================
--- tip.orig/fs/fhandle.c
+++ tip/fs/fhandle.c
@@ -117,10 +117,10 @@ static struct vfsmount *get_vfsmount_fro

if (fd == AT_FDCWD) {
struct fs_struct *fs = current->fs;
- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
path = fs->pwd;
mntget(path.mnt);
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
} else {
int fput_needed;
struct file *file = fget_light(fd, &fput_needed);
Index: tip/fs/fs_struct.c
===================================================================
--- tip.orig/fs/fs_struct.c
+++ tip/fs/fs_struct.c
@@ -26,13 +26,11 @@ void set_fs_root(struct fs_struct *fs, s
{
struct path old_root;

- spin_lock(&fs->lock);
- write_seqcount_begin(&fs->seq);
+ write_seqlock(&fs->lock);
old_root = fs->root;
fs->root = *path;
path_get_longterm(path);
- write_seqcount_end(&fs->seq);
- spin_unlock(&fs->lock);
+ write_sequnlock(&fs->lock);
if (old_root.dentry)
path_put_longterm(&old_root);
}
@@ -45,13 +43,11 @@ void set_fs_pwd(struct fs_struct *fs, st
{
struct path old_pwd;

- spin_lock(&fs->lock);
- write_seqcount_begin(&fs->seq);
+ write_seqlock(&fs->lock);
old_pwd = fs->pwd;
fs->pwd = *path;
path_get_longterm(path);
- write_seqcount_end(&fs->seq);
- spin_unlock(&fs->lock);
+ write_sequnlock(&fs->lock);

if (old_pwd.dentry)
path_put_longterm(&old_pwd);
@@ -68,8 +64,7 @@ void chroot_fs_refs(struct path *old_roo
task_lock(p);
fs = p->fs;
if (fs) {
- spin_lock(&fs->lock);
- write_seqcount_begin(&fs->seq);
+ write_seqlock(&fs->lock);
if (fs->root.dentry == old_root->dentry
&& fs->root.mnt == old_root->mnt) {
path_get_longterm(new_root);
@@ -82,8 +77,7 @@ void chroot_fs_refs(struct path *old_roo
fs->pwd = *new_root;
count++;
}
- write_seqcount_end(&fs->seq);
- spin_unlock(&fs->lock);
+ write_sequnlock(&fs->lock);
}
task_unlock(p);
} while_each_thread(g, p);
@@ -106,12 +100,10 @@ void exit_fs(struct task_struct *tsk)
if (fs) {
int kill;
task_lock(tsk);
- spin_lock(&fs->lock);
- write_seqcount_begin(&fs->seq);
+ write_seqlock(&fs->lock);
tsk->fs = NULL;
kill = !--fs->users;
- write_seqcount_end(&fs->seq);
- spin_unlock(&fs->lock);
+ write_sequnlock(&fs->lock);
task_unlock(tsk);
if (kill)
free_fs_struct(fs);
@@ -125,16 +117,15 @@ struct fs_struct *copy_fs_struct(struct
if (fs) {
fs->users = 1;
fs->in_exec = 0;
- spin_lock_init(&fs->lock);
- seqcount_init(&fs->seq);
+ seqlock_init(&fs->lock);
fs->umask = old->umask;

- spin_lock(&old->lock);
+ seq_spin_lock(&old->lock);
fs->root = old->root;
path_get_longterm(&fs->root);
fs->pwd = old->pwd;
path_get_longterm(&fs->pwd);
- spin_unlock(&old->lock);
+ seq_spin_unlock(&old->lock);
}
return fs;
}
@@ -149,10 +140,10 @@ int unshare_fs_struct(void)
return -ENOMEM;

task_lock(current);
- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
kill = !--fs->users;
current->fs = new_fs;
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
task_unlock(current);

if (kill)
@@ -171,8 +162,7 @@ EXPORT_SYMBOL(current_umask);
/* to be mentioned only in INIT_TASK */
struct fs_struct init_fs = {
.users = 1,
- .lock = __SPIN_LOCK_UNLOCKED(init_fs.lock),
- .seq = SEQCNT_ZERO,
+ .lock = __SEQLOCK_UNLOCKED(init_fs.lock),
.umask = 0022,
};

@@ -185,14 +175,14 @@ void daemonize_fs_struct(void)

task_lock(current);

- spin_lock(&init_fs.lock);
+ seq_spin_lock(&init_fs.lock);
init_fs.users++;
- spin_unlock(&init_fs.lock);
+ seq_spin_unlock(&init_fs.lock);

- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
current->fs = &init_fs;
kill = !--fs->users;
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);

task_unlock(current);
if (kill)
Index: tip/fs/namei.c
===================================================================
--- tip.orig/fs/namei.c
+++ tip/fs/namei.c
@@ -427,7 +427,7 @@ static int unlazy_walk(struct nameidata
BUG_ON(!(nd->flags & LOOKUP_RCU));
if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
want_root = 1;
- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
if (nd->root.mnt != fs->root.mnt ||
nd->root.dentry != fs->root.dentry)
goto err_root;
@@ -457,7 +457,7 @@ static int unlazy_walk(struct nameidata
spin_unlock(&parent->d_lock);
if (want_root) {
path_get(&nd->root);
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
}
mntget(nd->path.mnt);

@@ -472,7 +472,7 @@ err_parent:
spin_unlock(&parent->d_lock);
err_root:
if (want_root)
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
return -ECHILD;
}

@@ -566,10 +566,10 @@ static __always_inline void set_root_rcu
unsigned seq;

do {
- seq = read_seqcount_begin(&fs->seq);
+ seq = read_seqbegin(&fs->lock);
nd->root = fs->root;
nd->seq = __read_seqcount_begin(&nd->root.dentry->d_seq);
- } while (read_seqcount_retry(&fs->seq, seq));
+ } while (read_seqretry(&fs->lock, seq));
}
}

@@ -1545,10 +1545,10 @@ static int path_init(int dfd, const char
rcu_read_lock();

do {
- seq = read_seqcount_begin(&fs->seq);
+ seq = read_seqbegin(&fs->lock);
nd->path = fs->pwd;
nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
- } while (read_seqcount_retry(&fs->seq, seq));
+ } while (read_seqretry(&fs->lock, seq));
} else {
get_fs_pwd(current->fs, &nd->path);
}
Index: tip/include/linux/fs_struct.h
===================================================================
--- tip.orig/include/linux/fs_struct.h
+++ tip/include/linux/fs_struct.h
@@ -2,13 +2,11 @@
#define _LINUX_FS_STRUCT_H

#include <linux/path.h>
-#include <linux/spinlock.h>
#include <linux/seqlock.h>

struct fs_struct {
int users;
- spinlock_t lock;
- seqcount_t seq;
+ seqlock_t lock;
int umask;
int in_exec;
struct path root, pwd;
@@ -26,29 +24,29 @@ extern int unshare_fs_struct(void);

static inline void get_fs_root(struct fs_struct *fs, struct path *root)
{
- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
*root = fs->root;
path_get(root);
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
}

static inline void get_fs_pwd(struct fs_struct *fs, struct path *pwd)
{
- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
*pwd = fs->pwd;
path_get(pwd);
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
}

static inline void get_fs_root_and_pwd(struct fs_struct *fs, struct path *root,
struct path *pwd)
{
- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
*root = fs->root;
path_get(root);
*pwd = fs->pwd;
path_get(pwd);
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
}

#endif /* _LINUX_FS_STRUCT_H */
Index: tip/kernel/fork.c
===================================================================
--- tip.orig/kernel/fork.c
+++ tip/kernel/fork.c
@@ -876,13 +876,13 @@ static int copy_fs(unsigned long clone_f
struct fs_struct *fs = current->fs;
if (clone_flags & CLONE_FS) {
/* tsk->fs is already what we want */
- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
if (fs->in_exec) {
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
return -EAGAIN;
}
fs->users++;
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
return 0;
}
tsk->fs = copy_fs_struct(fs);
@@ -1757,13 +1757,13 @@ SYSCALL_DEFINE1(unshare, unsigned long,

if (new_fs) {
fs = current->fs;
- spin_lock(&fs->lock);
+ seq_spin_lock(&fs->lock);
current->fs = new_fs;
if (--fs->users)
new_fs = NULL;
else
new_fs = fs;
- spin_unlock(&fs->lock);
+ seq_spin_unlock(&fs->lock);
}

if (new_fd) {



\
 
 \ /
  Last update: 2012-03-15 12:47    [from the cache]
©2003-2011 Jasper Spaans