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Message-ID: <20090520230659.GC5956@ghostprotocols.net>
Date: Wed, 20 May 2009 20:06:59 -0300
From: Arnaldo Carvalho de Melo <acme@...hat.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, Chris Van Hoof <vanhoof@...hat.com>,
Clark Williams <williams@...hat.com>
Subject: [RFC 2/2] net: Allow protocols to provide an unlocked_recvmsg
sk_prot method
So that the socket layer kwows which protocol uses locking and can ask
for an unlocked recvmsg call inside recvmmsg, that takes the lock for a
batch of packets.
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
include/linux/socket.h | 3 ++
include/net/sock.h | 5 ++++
net/core/sock.c | 11 +++++++--
net/ipv4/udp.c | 52 ++++++++++++++++++++++++++++++++++++++++-------
net/socket.c | 39 ++++++++++++++++++++++++-----------
5 files changed, 87 insertions(+), 23 deletions(-)
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 50c6c44..7ef30a3 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -265,6 +265,9 @@ struct ucred {
#define MSG_ERRQUEUE 0x2000 /* Fetch message from error queue */
#define MSG_NOSIGNAL 0x4000 /* Do not generate SIGPIPE */
#define MSG_MORE 0x8000 /* Sender will send more */
+#ifdef __KERNEL__
+#define MSG_UNLOCKED 0x10000 /* Don't lock the sock */
+#endif
#define MSG_EOF MSG_FIN
diff --git a/include/net/sock.h b/include/net/sock.h
index da2ea5f..43c231c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -637,6 +637,11 @@ struct proto {
struct msghdr *msg,
size_t len, int noblock, int flags,
int *addr_len);
+ int (*unlocked_recvmsg)(struct kiocb *iocb,
+ struct sock *sk,
+ struct msghdr *msg,
+ size_t len, int noblock,
+ int flags, int *addr_len);
int (*sendpage)(struct sock *sk, struct page *page,
int offset, size_t size, int flags);
int (*bind)(struct sock *sk,
diff --git a/net/core/sock.c b/net/core/sock.c
index 9730820..2640ab7 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1918,11 +1918,16 @@ int sock_common_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t size, int flags)
{
struct sock *sk = sock->sk;
- int addr_len = 0;
int err;
+ int addr_len = 0;
+
+ BUG_ON((flags & MSG_UNLOCKED) &&
+ sk->sk_prot->unlocked_recvmsg == NULL);
- err = sk->sk_prot->recvmsg(iocb, sk, msg, size, flags & MSG_DONTWAIT,
- flags & ~MSG_DONTWAIT, &addr_len);
+ err = ((flags & MSG_UNLOCKED) ?
+ sk->sk_prot->unlocked_recvmsg :
+ sk->sk_prot->recvmsg)(iocb, sk, msg, size, flags & MSG_DONTWAIT,
+ flags & ~MSG_DONTWAIT, &addr_len);
if (err >= 0)
msg->msg_namelen = addr_len;
return err;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 7a1d1ce..4c6e994 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -871,13 +871,35 @@ int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
return 0;
}
+static void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb)
+{
+ lock_sock(sk);
+ skb_free_datagram(sk, skb);
+ release_sock(sk);
+}
+
+static int skb_kill_datagram_locked(struct sock *sk, struct sk_buff *skb,
+ unsigned int flags)
+{
+ int ret;
+ lock_sock(sk);
+ ret = skb_kill_datagram(sk, skb, flags);
+ release_sock(sk);
+ return ret;
+}
+
/*
* This should be easy, if there is something there we
* return it, otherwise we block.
*/
-int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
- size_t len, int noblock, int flags, int *addr_len)
+static int __udp_recvmsg(struct kiocb *iocb, struct sock *sk,
+ struct msghdr *msg, size_t len, int noblock,
+ int flags, int *addr_len,
+ void (*free_datagram)(struct sock *,
+ struct sk_buff *),
+ int (*kill_datagram)(struct sock *,
+ struct sk_buff *, unsigned int))
{
struct inet_sock *inet = inet_sk(sk);
struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
@@ -955,23 +977,36 @@ try_again:
err = ulen;
out_free:
- lock_sock(sk);
- skb_free_datagram(sk, skb);
- release_sock(sk);
+ free_datagram(sk, skb);
out:
return err;
csum_copy_err:
- lock_sock(sk);
- if (!skb_kill_datagram(sk, skb, flags))
+ if (!kill_datagram(sk, skb, flags))
UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
- release_sock(sk);
if (noblock)
return -EAGAIN;
goto try_again;
}
+int udp_recvmsg(struct kiocb *iocb, struct sock *sk,
+ struct msghdr *msg, size_t len, int noblock,
+ int flags, int *addr_len)
+{
+ return __udp_recvmsg(iocb, sk, msg, len, noblock, flags, addr_len,
+ skb_free_datagram_locked,
+ skb_kill_datagram_locked);
+}
+
+int udp_unlocked_recvmsg(struct kiocb *iocb, struct sock *sk,
+ struct msghdr *msg, size_t len, int noblock,
+ int flags, int *addr_len)
+{
+ return __udp_recvmsg(iocb, sk, msg, len, noblock, flags, addr_len,
+ skb_free_datagram, skb_kill_datagram);
+}
+
int udp_disconnect(struct sock *sk, int flags)
{
@@ -1564,6 +1599,7 @@ struct proto udp_prot = {
.getsockopt = udp_getsockopt,
.sendmsg = udp_sendmsg,
.recvmsg = udp_recvmsg,
+ .unlocked_recvmsg = udp_unlocked_recvmsg,
.sendpage = udp_sendpage,
.backlog_rcv = __udp_queue_rcv_skb,
.hash = udp_lib_hash,
diff --git a/net/socket.c b/net/socket.c
index f0249cb..3ab1520 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2084,29 +2084,23 @@ out:
* Linux recvmmsg interface
*/
-SYSCALL_DEFINE4(recvmmsg, int, fd, struct mmsghdr __user *, mmsg,
- unsigned int, vlen, unsigned int, flags)
+static int __sys_recvmmsg(struct socket *sock, struct mmsghdr __user *mmsg,
+ unsigned vlen, unsigned flags)
{
- int fput_needed, err, datagrams = 0;
- struct socket *sock = sockfd_lookup_light(fd, &err, &fput_needed);
+ int err, datagrams = 0;
struct mmsghdr __user *entry = mmsg;
- if (!sock)
- goto out;
-
while (datagrams < vlen) {
err = __sys_recvmsg(sock, (struct msghdr __user *)entry, flags);
if (err < 0)
- goto out_put;
+ break;
err = __put_user(err, &entry->msg_len);
if (err)
- goto out_put;
+ break;
++entry;
++datagrams;
}
-out_put:
- fput_light(sock->file, fput_needed);
-out:
+
/*
* We may return less entries than requested (vlen) if the
* sock is non block and there aren't enough datagrams.
@@ -2116,6 +2110,27 @@ out:
return err;
}
+SYSCALL_DEFINE4(recvmmsg, int, fd, struct mmsghdr __user *, mmsg,
+ unsigned int, vlen, unsigned int, flags)
+{
+ int fput_needed, err;
+ struct socket *sock = sockfd_lookup_light(fd, &err, &fput_needed);
+
+ if (!sock)
+ goto out;
+
+ if (sock->sk->sk_prot->unlocked_recvmsg) {
+ lock_sock(sock->sk);
+ err = __sys_recvmmsg(sock, mmsg, vlen, flags | MSG_UNLOCKED);
+ release_sock(sock->sk);
+ } else
+ err = __sys_recvmmsg(sock, mmsg, vlen, flags);
+
+ fput_light(sock->file, fput_needed);
+out:
+ return err;
+}
+
#ifdef __ARCH_WANT_SYS_SOCKETCALL
/* Argument list sizes for sys_socketcall */
--
1.6.0.6
--
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