Using the net-internal helper __sys_recvfrom() allows us to avoid the internal calls to the sys_recvfrom() syscall. 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@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: David S. Miller <davem@xxxxxxxxxxxxx> Cc: netdev@xxxxxxxxxxxxxxx Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> --- include/linux/socket.h | 6 ++++++ net/compat.c | 3 ++- net/socket.c | 21 +++++++++++++-------- 3 files changed, 21 insertions(+), 9 deletions(-) diff --git a/include/linux/socket.h b/include/linux/socket.h index 9286a5a8c60c..40cc93b91628 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -353,4 +353,10 @@ extern int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen unsigned int flags, struct timespec *timeout); extern int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, unsigned int flags); + +/* helpers which do the actual work for syscalls */ +extern int __sys_recvfrom(int fd, void __user *ubuf, size_t size, + unsigned int flags, struct sockaddr __user *addr, + int __user *addr_len); + #endif /* _LINUX_SOCKET_H */ diff --git a/net/compat.c b/net/compat.c index 22381719718c..2d8186c277b2 100644 --- a/net/compat.c +++ b/net/compat.c @@ -760,7 +760,8 @@ COMPAT_SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, buf, compat_size_t, len unsigned int, flags, struct sockaddr __user *, addr, int __user *, addrlen) { - return sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, addr, addrlen); + return __sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, addr, + addrlen); } COMPAT_SYSCALL_DEFINE5(recvmmsg, int, fd, struct compat_mmsghdr __user *, mmsg, diff --git a/net/socket.c b/net/socket.c index a93c99b518ca..712d99d8680f 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1767,10 +1767,8 @@ SYSCALL_DEFINE4(send, int, fd, void __user *, buff, size_t, len, * sender. We verify the buffers are writable and if needed move the * sender address from kernel to user space. */ - -SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size, - unsigned int, flags, struct sockaddr __user *, addr, - int __user *, addr_len) +int __sys_recvfrom(int fd, void __user *ubuf, size_t size, unsigned int flags, + struct sockaddr __user *addr, int __user *addr_len) { struct socket *sock; struct iovec iov; @@ -1810,6 +1808,13 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size, return err; } +SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size, + unsigned int, flags, struct sockaddr __user *, addr, + int __user *, addr_len) +{ + return __sys_recvfrom(fd, ubuf, size, flags, addr, addr_len); +} + /* * Receive a datagram from a socket. */ @@ -1817,7 +1822,7 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size, SYSCALL_DEFINE4(recv, int, fd, void __user *, ubuf, size_t, size, unsigned int, flags) { - return sys_recvfrom(fd, ubuf, size, flags, NULL, NULL); + return __sys_recvfrom(fd, ubuf, size, flags, NULL, NULL); } /* @@ -2486,9 +2491,9 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args) err = sys_recv(a0, (void __user *)a1, a[2], a[3]); break; case SYS_RECVFROM: - err = sys_recvfrom(a0, (void __user *)a1, a[2], a[3], - (struct sockaddr __user *)a[4], - (int __user *)a[5]); + err = __sys_recvfrom(a0, (void __user *)a1, a[2], a[3], + (struct sockaddr __user *)a[4], + (int __user *)a[5]); break; case SYS_SHUTDOWN: err = sys_shutdown(a0, a1); -- 2.16.3
