Commit fd4e82f5 authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

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

Using the net-internal helper __compat_sys_recvfrom() allows us to avoid
the internal calls to the compat_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@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 d27e9afc

net/compat.c

+16 −7
Original line number Diff line number Diff line
@@ -753,18 +753,25 @@ COMPAT_SYSCALL_DEFINE3(recvmsg, int, fd, struct compat_msghdr __user *, msg, uns 
			     flags | MSG_CMSG_COMPAT, false);

}



static inline long __compat_sys_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);

}



COMPAT_SYSCALL_DEFINE4(recv, int, fd, void __user *, buf, compat_size_t, len, unsigned int, flags)

{

	return __sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, NULL,

			      NULL);

	return __compat_sys_recvfrom(fd, buf, len, flags, NULL, NULL);

}



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 __compat_sys_recvfrom(fd, buf, len, flags, addr, addrlen);

}



COMPAT_SYSCALL_DEFINE5(recvmmsg, int, fd, struct compat_mmsghdr __user *, mmsg,
@@ -845,11 +852,13 @@ COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args) 
				   compat_ptr(a[4]), a[5]);

		break;

	case SYS_RECV:

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

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

					    NULL, NULL);

		break;

	case SYS_RECVFROM:

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

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

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

					    compat_ptr(a[4]),

					    compat_ptr(a[5]));

		break;

	case SYS_SHUTDOWN:

		ret = __sys_shutdown(a0, a1);