teach set_nameidata() to handle setting the root as well

That way we don't need the callers to mess with manually setting any fields
of nameidata instances.  Old set_nameidata() gets renamed (__set_nameidata()),
new becomes an inlined helper that takes a struct path pointer and deals
with setting nd->root and putting ND_ROOT_PRESET in nd->state when new
argument is non-NULL.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2021-04-01 22:28:03 -04:00
Родитель bcba1e7d0d
Коммит 06422964c8
1 изменённых файлов: 16 добавлений и 12 удалений

Просмотреть файл

@ -577,7 +577,7 @@ struct nameidata {
#define ND_ROOT_GRABBED 2
#define ND_JUMPED 4
static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
static void __set_nameidata(struct nameidata *p, int dfd, struct filename *name)
{
struct nameidata *old = current->nameidata;
p->stack = p->internal;
@ -587,10 +587,20 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
p->path.dentry = NULL;
p->total_link_count = old ? old->total_link_count : 0;
p->saved = old;
p->state = 0;
current->nameidata = p;
}
static inline void set_nameidata(struct nameidata *p, int dfd, struct filename *name,
const struct path *root)
{
__set_nameidata(p, dfd, name);
p->state = 0;
if (unlikely(root)) {
p->state = ND_ROOT_PRESET;
p->root = *root;
}
}
static void restore_nameidata(void)
{
struct nameidata *now = current->nameidata, *old = now->saved;
@ -2454,11 +2464,7 @@ int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct nameidata nd;
if (IS_ERR(name))
return PTR_ERR(name);
set_nameidata(&nd, dfd, name);
if (unlikely(root)) {
nd.root = *root;
nd.state = ND_ROOT_PRESET;
}
set_nameidata(&nd, dfd, name, root);
retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
if (unlikely(retval == -ECHILD))
retval = path_lookupat(&nd, flags, path);
@ -2499,7 +2505,7 @@ static struct filename *filename_parentat(int dfd, struct filename *name,
if (IS_ERR(name))
return name;
set_nameidata(&nd, dfd, name);
set_nameidata(&nd, dfd, name, NULL);
retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
if (unlikely(retval == -ECHILD))
retval = path_parentat(&nd, flags, parent);
@ -3530,7 +3536,7 @@ struct file *do_filp_open(int dfd, struct filename *pathname,
int flags = op->lookup_flags;
struct file *filp;
set_nameidata(&nd, dfd, pathname);
set_nameidata(&nd, dfd, pathname, NULL);
filp = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(filp == ERR_PTR(-ECHILD)))
filp = path_openat(&nd, op, flags);
@ -3555,9 +3561,7 @@ struct file *do_file_open_root(const struct path *root,
if (IS_ERR(filename))
return ERR_CAST(filename);
set_nameidata(&nd, -1, filename);
nd.root = *root;
nd.state = ND_ROOT_PRESET;
set_nameidata(&nd, -1, filename, root);
file = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
file = path_openat(&nd, op, flags);