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Commit 211b634b authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

net: socket: add __sys_sendto() helper; remove in-kernel call to syscall 

Using the net-internal helper __sys_sendto() allows us to avoid the
internal calls to the sys_sendto() 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@light.dominikbrodowski.net



Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
parent 7a09e1eb

include/linux/socket.h

+3 −0
Original line number Diff line number Diff line
@@ -358,5 +358,8 @@ extern int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, 
extern int __sys_recvfrom(int fd, void __user *ubuf, size_t size,

			  unsigned int flags, struct sockaddr __user *addr,

			  int __user *addr_len);

extern int __sys_sendto(int fd, void __user *buff, size_t len,

			unsigned int flags, struct sockaddr __user *addr,

			int addr_len);



#endif /* _LINUX_SOCKET_H */

net/compat.c

+2 −1
Original line number Diff line number Diff line
@@ -838,7 +838,8 @@ COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args) 
		ret = sys_send(a0, compat_ptr(a1), a[2], a[3]);

		break;

	case SYS_SENDTO:

		ret = sys_sendto(a0, compat_ptr(a1), a[2], a[3], compat_ptr(a[4]), a[5]);

		ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3],

				   compat_ptr(a[4]), a[5]);

		break;

	case SYS_RECV:

		ret = compat_sys_recv(a0, compat_ptr(a1), a[2], a[3]);

net/socket.c

+12 −7
Original line number Diff line number Diff line
@@ -1711,10 +1711,8 @@ SYSCALL_DEFINE3(getpeername, int, fd, struct sockaddr __user *, usockaddr, 
 *	space and check the user space data area is readable before invoking

 *	the protocol.

 */



SYSCALL_DEFINE6(sendto, int, fd, void __user *, buff, size_t, len,

		unsigned int, flags, struct sockaddr __user *, addr,

		int, addr_len)

int __sys_sendto(int fd, void __user *buff, size_t len, unsigned int flags,

		 struct sockaddr __user *addr,  int addr_len)

{

	struct socket *sock;

	struct sockaddr_storage address;
@@ -1752,6 +1750,13 @@ SYSCALL_DEFINE6(sendto, int, fd, void __user *, buff, size_t, len, 
	return err;

}



SYSCALL_DEFINE6(sendto, int, fd, void __user *, buff, size_t, len,

		unsigned int, flags, struct sockaddr __user *, addr,

		int, addr_len)

{

	return __sys_sendto(fd, buff, len, flags, addr, addr_len);

}



/*

 *	Send a datagram down a socket.

 */
@@ -1759,7 +1764,7 @@ SYSCALL_DEFINE6(sendto, int, fd, void __user *, buff, size_t, len, 
SYSCALL_DEFINE4(send, int, fd, void __user *, buff, size_t, len,

		unsigned int, flags)

{

	return sys_sendto(fd, buff, len, flags, NULL, 0);

	return __sys_sendto(fd, buff, len, flags, NULL, 0);

}



/*
@@ -2484,7 +2489,7 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args) 
		err = sys_send(a0, (void __user *)a1, a[2], a[3]);

		break;

	case SYS_SENDTO:

		err = sys_sendto(a0, (void __user *)a1, a[2], a[3],

		err = __sys_sendto(a0, (void __user *)a1, a[2], a[3],

				   (struct sockaddr __user *)a[4], a[5]);

		break;

	case SYS_RECV: