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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: Dominik Brodowski <linux@dominikbrodowski.net>
hifive-unleashed-5.1
Dominik Brodowski 2018-03-13 19:18:52 +01:00
parent 7a09e1eb9c
commit 211b634b7f
3 changed files with 17 additions and 8 deletions
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3
include/linux/socket.h
View File

@ -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 */

3
net/compat.c
View File

@ -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]);

19
net/socket.c
View File

@ -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 @@ out:
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 @@ out:
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);
}
/*
@ -2484,8 +2489,8 @@ 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],
(struct sockaddr __user *)a[4], a[5]);
err = __sys_sendto(a0, (void __user *)a1, a[2], a[3],
(struct sockaddr __user *)a[4], a[5]);
break;
case SYS_RECV:
err = sys_recv(a0, (void __user *)a1, a[2], a[3]);