fs: add do_symlinkat() helper and ksys_symlink() wrapper; remove in-kernel calls to syscall
Using the fs-internal do_symlinkat() helper allows us to get rid of fs-internal calls to the sys_symlinkat() syscall. Introducing the ksys_symlink() wrapper allows us to avoid the in-kernel calls to the sys_symlink() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_symlink(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
parent
0101db7a30
commit
b724e846b4
|
@ -58,6 +58,8 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
|
|||
long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
|
||||
long do_rmdir(int dfd, const char __user *pathname);
|
||||
long do_unlinkat(int dfd, struct filename *name);
|
||||
long do_symlinkat(const char __user *oldname, int newdfd,
|
||||
const char __user *newname);
|
||||
|
||||
/*
|
||||
* namespace.c
|
||||
|
|
12
fs/namei.c
12
fs/namei.c
|
@ -4113,8 +4113,8 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
|
|||
}
|
||||
EXPORT_SYMBOL(vfs_symlink);
|
||||
|
||||
SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
|
||||
int, newdfd, const char __user *, newname)
|
||||
long do_symlinkat(const char __user *oldname, int newdfd,
|
||||
const char __user *newname)
|
||||
{
|
||||
int error;
|
||||
struct filename *from;
|
||||
|
@ -4144,9 +4144,15 @@ out_putname:
|
|||
return error;
|
||||
}
|
||||
|
||||
SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
|
||||
int, newdfd, const char __user *, newname)
|
||||
{
|
||||
return do_symlinkat(oldname, newdfd, newname);
|
||||
}
|
||||
|
||||
SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname)
|
||||
{
|
||||
return sys_symlinkat(oldname, AT_FDCWD, newname);
|
||||
return do_symlinkat(oldname, AT_FDCWD, newname);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
|
@ -979,4 +979,13 @@ static inline long ksys_mkdir(const char __user *pathname, umode_t mode)
|
|||
return do_mkdirat(AT_FDCWD, pathname, mode);
|
||||
}
|
||||
|
||||
extern long do_symlinkat(const char __user *oldname, int newdfd,
|
||||
const char __user *newname);
|
||||
|
||||
static inline long ksys_symlink(const char __user *oldname,
|
||||
const char __user *newname)
|
||||
{
|
||||
return do_symlinkat(oldname, AT_FDCWD, newname);
|
||||
}
|
||||
|
||||
#endif
|
||||
|
|
|
@ -392,7 +392,7 @@ static int __init do_symlink(void)
|
|||
{
|
||||
collected[N_ALIGN(name_len) + body_len] = '\0';
|
||||
clean_path(collected, 0);
|
||||
sys_symlink(collected + N_ALIGN(name_len), collected);
|
||||
ksys_symlink(collected + N_ALIGN(name_len), collected);
|
||||
sys_lchown(collected, uid, gid);
|
||||
do_utime(collected, mtime);
|
||||
state = SkipIt;
|
||||
|
|
Loading…
Reference in a new issue