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[PATCH] fs/namei.c: replace multiple current->fs by shortcut variable 

Replace current->fs by fs helper variable to reduce some indirection
overhead and (at least at the moment, before the current_thread_info() %gs
PDA improvement is available) get rid of more costly current references.
Reduces fs/namei.o from 37786 to 37082 Bytes (704 Bytes saved).

[akpm@osdl.org: cleanup]
Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andreas Mohr 2006-09-29 02:01:22 -07:00 committed by Linus Torvalds
parent c16a02d6f5
commit e518ddb7ba
1 changed files with 47 additions and 39 deletions
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86
fs/namei.c
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@ -518,18 +518,20 @@ static int __emul_lookup_dentry(const char *, struct nameidata *);
static __always_inline int
walk_init_root(const char *name, struct nameidata *nd)
{
read_lock(&current->fs->lock);
if (current->fs->altroot && !(nd->flags & LOOKUP_NOALT)) {
nd->mnt = mntget(current->fs->altrootmnt);
nd->dentry = dget(current->fs->altroot);
read_unlock(&current->fs->lock);
struct fs_struct *fs = current->fs;
read_lock(&fs->lock);
if (fs->altroot && !(nd->flags & LOOKUP_NOALT)) {
nd->mnt = mntget(fs->altrootmnt);
nd->dentry = dget(fs->altroot);
read_unlock(&fs->lock);
if (__emul_lookup_dentry(name,nd))
return 0;
read_lock(&current->fs->lock);
read_lock(&fs->lock);
}
nd->mnt = mntget(current->fs->rootmnt);
nd->dentry = dget(current->fs->root);
read_unlock(&current->fs->lock);
nd->mnt = mntget(fs->rootmnt);
nd->dentry = dget(fs->root);
read_unlock(&fs->lock);
return 1;
}
@ -724,17 +726,19 @@ int follow_down(struct vfsmount **mnt, struct dentry **dentry)
static __always_inline void follow_dotdot(struct nameidata *nd)
{
struct fs_struct *fs = current->fs;
while(1) {
struct vfsmount *parent;
struct dentry *old = nd->dentry;
read_lock(&current->fs->lock);
if (nd->dentry == current->fs->root &&
nd->mnt == current->fs->rootmnt) {
read_unlock(&current->fs->lock);
read_lock(&fs->lock);
if (nd->dentry == fs->root &&
nd->mnt == fs->rootmnt) {
read_unlock(&fs->lock);
break;
}
read_unlock(&current->fs->lock);
read_unlock(&fs->lock);
spin_lock(&dcache_lock);
if (nd->dentry != nd->mnt->mnt_root) {
nd->dentry = dget(nd->dentry->d_parent);
@ -1042,15 +1046,17 @@ static int __emul_lookup_dentry(const char *name, struct nameidata *nd)
struct vfsmount *old_mnt = nd->mnt;
struct qstr last = nd->last;
int last_type = nd->last_type;
struct fs_struct *fs = current->fs;
/*
* NAME was not found in alternate root or it's a directory. Try to find
* it in the normal root:
* NAME was not found in alternate root or it's a directory.
* Try to find it in the normal root:
*/
nd->last_type = LAST_ROOT;
read_lock(&current->fs->lock);
nd->mnt = mntget(current->fs->rootmnt);
nd->dentry = dget(current->fs->root);
read_unlock(&current->fs->lock);
read_lock(&fs->lock);
nd->mnt = mntget(fs->rootmnt);
nd->dentry = dget(fs->root);
read_unlock(&fs->lock);
if (path_walk(name, nd) == 0) {
if (nd->dentry->d_inode) {
dput(old_dentry);
@ -1074,6 +1080,7 @@ void set_fs_altroot(void)
struct vfsmount *mnt = NULL, *oldmnt;
struct dentry *dentry = NULL, *olddentry;
int err;
struct fs_struct *fs = current->fs;
if (!emul)
goto set_it;
@ -1083,12 +1090,12 @@ void set_fs_altroot(void)
dentry = nd.dentry;
}
set_it:
write_lock(&current->fs->lock);
oldmnt = current->fs->altrootmnt;
olddentry = current->fs->altroot;
current->fs->altrootmnt = mnt;
current->fs->altroot = dentry;
write_unlock(&current->fs->lock);
write_lock(&fs->lock);
oldmnt = fs->altrootmnt;
olddentry = fs->altroot;
fs->altrootmnt = mnt;
fs->altroot = dentry;
write_unlock(&fs->lock);
if (olddentry) {
dput(olddentry);
mntput(oldmnt);
@ -1102,29 +1109,30 @@ static int fastcall do_path_lookup(int dfd, const char *name,
int retval = 0;
int fput_needed;
struct file *file;
struct fs_struct *fs = current->fs;
nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags;
nd->depth = 0;
if (*name=='/') {
read_lock(&current->fs->lock);
if (current->fs->altroot && !(nd->flags & LOOKUP_NOALT)) {
nd->mnt = mntget(current->fs->altrootmnt);
nd->dentry = dget(current->fs->altroot);
read_unlock(&current->fs->lock);
read_lock(&fs->lock);
if (fs->altroot && !(nd->flags & LOOKUP_NOALT)) {
nd->mnt = mntget(fs->altrootmnt);
nd->dentry = dget(fs->altroot);
read_unlock(&fs->lock);
if (__emul_lookup_dentry(name,nd))
goto out; /* found in altroot */
read_lock(&current->fs->lock);
read_lock(&fs->lock);
}
nd->mnt = mntget(current->fs->rootmnt);
nd->dentry = dget(current->fs->root);
read_unlock(&current->fs->lock);
nd->mnt = mntget(fs->rootmnt);
nd->dentry = dget(fs->root);
read_unlock(&fs->lock);
} else if (dfd == AT_FDCWD) {
read_lock(&current->fs->lock);
nd->mnt = mntget(current->fs->pwdmnt);
nd->dentry = dget(current->fs->pwd);
read_unlock(&current->fs->lock);
read_lock(&fs->lock);
nd->mnt = mntget(fs->pwdmnt);
nd->dentry = dget(fs->pwd);
read_unlock(&fs->lock);
} else {
struct dentry *dentry;