[PATCH v2 1/3] fs: add ksys_lsetxattr() wrapper

From: Roberto Sassu
Date: Thu May 09 2019 - 07:29:19 EST


Similarly to commit 03450e271a16 ("fs: add ksys_fchmod() and do_fchmodat()
helpers and ksys_chmod() wrapper; remove in-kernel calls to syscall"), this
patch introduces the ksys_lsetxattr() helper to avoid in-kernel calls to
the sys_lsetxattr() syscall.

Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
---
fs/xattr.c | 9 ++++++++-
include/linux/syscalls.h | 3 +++
2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 0d6a6a4af861..422b3d481edb 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -484,11 +484,18 @@ SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
}

+int ksys_lsetxattr(const char __user *pathname,
+ const char __user *name, const void __user *value,
+ size_t size, int flags)
+{
+ return path_setxattr(pathname, name, value, size, flags, 0);
+}
+
SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
const char __user *, name, const void __user *, value,
size_t, size, int, flags)
{
- return path_setxattr(pathname, name, value, size, flags, 0);
+ return ksys_lsetxattr(pathname, name, value, size, flags);
}

SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e446806a561f..b639f13cd1f8 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1260,6 +1260,9 @@ int ksys_ipc(unsigned int call, int first, unsigned long second,
unsigned long third, void __user * ptr, long fifth);
int compat_ksys_ipc(u32 call, int first, int second,
u32 third, u32 ptr, u32 fifth);
+int ksys_lsetxattr(const char __user *pathname,
+ const char __user *name, const void __user *value,
+ size_t size, int flags);

/*
* The following kernel syscall equivalents are just wrappers to fs-internal
--
2.17.1