[PATCH -next 20/22] net: socket: add __compat_sys_getsockopt() helper; remove in-kernel call to compat syscall

From: Dominik Brodowski
Date: Fri Mar 16 2018 - 13:07:12 EST


Using the net-internal helper __compat_sys_getsockopt() allows us to avoid
the internal calls to the compat_sys_getsockopt() syscall.

Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
---
net/compat.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/net/compat.c b/net/compat.c
index 75bfcbbb2e3e..cdf5b0c1b962 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -509,8 +509,9 @@ int compat_sock_get_timestampns(struct sock *sk, struct timespec __user *usersta
}
EXPORT_SYMBOL(compat_sock_get_timestampns);

-COMPAT_SYSCALL_DEFINE5(getsockopt, int, fd, int, level, int, optname,
- char __user *, optval, int __user *, optlen)
+static int __compat_sys_getsockopt(int fd, int level, int optname,
+ char __user *optval,
+ int __user *optlen)
{
int err;
struct socket *sock = sockfd_lookup(fd, &err);
@@ -536,6 +537,12 @@ COMPAT_SYSCALL_DEFINE5(getsockopt, int, fd, int, level, int, optname,
return err;
}

+COMPAT_SYSCALL_DEFINE5(getsockopt, int, fd, int, level, int, optname,
+ char __user *, optval, int __user *, optlen)
+{
+ return __compat_sys_getsockopt(fd, level, optname, optval, optlen);
+}
+
struct compat_group_req {
__u32 gr_interface;
struct __kernel_sockaddr_storage gr_group
@@ -874,8 +881,9 @@ COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args)
compat_ptr(a[3]), a[4]);
break;
case SYS_GETSOCKOPT:
- ret = compat_sys_getsockopt(a0, a1, a[2],
- compat_ptr(a[3]), compat_ptr(a[4]));
+ ret = __compat_sys_getsockopt(a0, a1, a[2],
+ compat_ptr(a[3]),
+ compat_ptr(a[4]));
break;
case SYS_SENDMSG:
ret = compat_sys_sendmsg(a0, compat_ptr(a1), a[2]);
--
2.16.2