af_unix: get rid of splice_read remnants
... including the rest of misguided 73ed5d25dc -
the real solution there was to quit unlocking/relocking the
socket. Unfortunately, the other kludge ("use freezable
sleep in ->recvmsg(); whaddya mean 'somebody might hold
a lock when calling it'?" is not so easily killed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 9e28d9d..0fdb887 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2240,33 +2240,21 @@ static unsigned int unix_skb_len(const struct sk_buff *skb)
return skb->len - UNIXCB(skb).consumed;
}
-struct unix_stream_read_state {
- int (*recv_actor)(struct sk_buff *, int, int,
- struct unix_stream_read_state *);
- struct socket *socket;
- struct msghdr *msg;
- struct pipe_inode_info *pipe;
- size_t size;
- int flags;
-};
-
-static int unix_stream_read_generic(struct unix_stream_read_state *state,
- bool freezable)
+static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
+ size_t size, int flags)
{
struct scm_cookie scm;
- struct socket *sock = state->socket;
struct sock *sk = sock->sk;
struct unix_sock *u = unix_sk(sk);
int copied = 0;
- int flags = state->flags;
int noblock = flags & MSG_DONTWAIT;
bool check_creds = false;
int target;
int err = 0;
long timeo;
int skip;
- size_t size = state->size;
unsigned int last_len;
+ bool freezable = !(msg->msg_iter.type & ITER_PIPE);
if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
err = -EINVAL;
@@ -2295,7 +2283,6 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state,
do {
int chunk;
- bool drop_skb;
struct sk_buff *skb, *last;
redo:
@@ -2369,20 +2356,16 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state,
}
/* Copy address just once */
- if (state->msg && state->msg->msg_name) {
+ if (msg->msg_name) {
DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
- state->msg->msg_name);
- unix_copy_addr(state->msg, skb->sk);
+ msg->msg_name);
+ unix_copy_addr(msg, skb->sk);
sunaddr = NULL;
}
chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
- skb_get(skb);
- chunk = state->recv_actor(skb, skip, chunk, state);
- drop_skb = !unix_skb_len(skb);
- /* skb is only safe to use if !drop_skb */
- consume_skb(skb);
- if (chunk < 0) {
+ if (skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
+ msg, chunk)) {
if (copied == 0)
copied = -EFAULT;
break;
@@ -2390,18 +2373,6 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state,
copied += chunk;
size -= chunk;
- if (drop_skb) {
- /* the skb was touched by a concurrent reader;
- * we should not expect anything from this skb
- * anymore and assume it invalid - we can be
- * sure it was dropped from the socket queue
- *
- * let's report a short read
- */
- err = 0;
- break;
- }
-
/* Mark read part of skb as used */
if (!(flags & MSG_PEEK)) {
UNIXCB(skb).consumed += chunk;
@@ -2443,39 +2414,12 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state,
} while (size);
mutex_unlock(&u->iolock);
- if (state->msg)
- scm_recv(sock, state->msg, &scm, flags);
- else
- scm_destroy(&scm);
+ if (msg)
+ scm_recv(sock, msg, &scm, flags);
out:
return copied ? : err;
}
-static int unix_stream_read_actor(struct sk_buff *skb,
- int skip, int chunk,
- struct unix_stream_read_state *state)
-{
- int ret;
-
- ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
- state->msg, chunk);
- return ret ?: chunk;
-}
-
-static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
- size_t size, int flags)
-{
- struct unix_stream_read_state state = {
- .recv_actor = unix_stream_read_actor,
- .socket = sock,
- .msg = msg,
- .size = size,
- .flags = flags
- };
-
- return unix_stream_read_generic(&state, true);
-}
-
static int unix_shutdown(struct socket *sock, int mode)
{
struct sock *sk = sock->sk;
