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Subject[PATCH 4.19 07/24] Revert "net: simplify sock_poll_wait"
Date
4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Karsten Graul <kgraul@linux.ibm.com>

[ Upstream commit 89ab066d4229acd32e323f1569833302544a4186 ]

This reverts commit dd979b4df817e9976f18fb6f9d134d6bc4a3c317.

This broke tcp_poll for SMC fallback: An AF_SMC socket establishes an
internal TCP socket for the initial handshake with the remote peer.
Whenever the SMC connection can not be established this TCP socket is
used as a fallback. All socket operations on the SMC socket are then
forwarded to the TCP socket. In case of poll, the file->private_data
pointer references the SMC socket because the TCP socket has no file
assigned. This causes tcp_poll to wait on the wrong socket.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
crypto/af_alg.c | 2 +-
include/net/sock.h | 12 +++++++++---
net/atm/common.c | 2 +-
net/caif/caif_socket.c | 2 +-
net/core/datagram.c | 2 +-
net/dccp/proto.c | 2 +-
net/ipv4/tcp.c | 2 +-
net/iucv/af_iucv.c | 2 +-
net/nfc/llcp_sock.c | 2 +-
net/rxrpc/af_rxrpc.c | 2 +-
net/smc/af_smc.c | 2 +-
net/tipc/socket.c | 2 +-
net/unix/af_unix.c | 4 ++--
13 files changed, 22 insertions(+), 16 deletions(-)

--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1071,7 +1071,7 @@ __poll_t af_alg_poll(struct file *file,
struct af_alg_ctx *ctx = ask->private;
__poll_t mask;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
mask = 0;

if (!ctx->more || ctx->used)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2057,14 +2057,20 @@ static inline bool skwq_has_sleeper(stru
/**
* sock_poll_wait - place memory barrier behind the poll_wait call.
* @filp: file
+ * @sock: socket to wait on
* @p: poll_table
*
* See the comments in the wq_has_sleeper function.
+ *
+ * Do not derive sock from filp->private_data here. An SMC socket establishes
+ * an internal TCP socket that is used in the fallback case. All socket
+ * operations on the SMC socket are then forwarded to the TCP socket. In case of
+ * poll, the filp->private_data pointer references the SMC socket because the
+ * TCP socket has no file assigned.
*/
-static inline void sock_poll_wait(struct file *filp, poll_table *p)
+static inline void sock_poll_wait(struct file *filp, struct socket *sock,
+ poll_table *p)
{
- struct socket *sock = filp->private_data;
-
if (!poll_does_not_wait(p)) {
poll_wait(filp, &sock->wq->wait, p);
/* We need to be sure we are in sync with the
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -653,7 +653,7 @@ __poll_t vcc_poll(struct file *file, str
struct atm_vcc *vcc;
__poll_t mask;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
mask = 0;

vcc = ATM_SD(sock);
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -941,7 +941,7 @@ static __poll_t caif_poll(struct file *f
__poll_t mask;
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
mask = 0;

/* exceptional events? */
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -838,7 +838,7 @@ __poll_t datagram_poll(struct file *file
struct sock *sk = sock->sk;
__poll_t mask;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
mask = 0;

/* exceptional events? */
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -325,7 +325,7 @@ __poll_t dccp_poll(struct file *file, st
__poll_t mask;
struct sock *sk = sock->sk;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
if (sk->sk_state == DCCP_LISTEN)
return inet_csk_listen_poll(sk);

--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -507,7 +507,7 @@ __poll_t tcp_poll(struct file *file, str
const struct tcp_sock *tp = tcp_sk(sk);
int state;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);

state = inet_sk_state_load(sk);
if (state == TCP_LISTEN)
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1505,7 +1505,7 @@ __poll_t iucv_sock_poll(struct file *fil
struct sock *sk = sock->sk;
__poll_t mask = 0;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);

if (sk->sk_state == IUCV_LISTEN)
return iucv_accept_poll(sk);
--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -556,7 +556,7 @@ static __poll_t llcp_sock_poll(struct fi

pr_debug("%p\n", sk);

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);

if (sk->sk_state == LLCP_LISTEN)
return llcp_accept_poll(sk);
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -741,7 +741,7 @@ static __poll_t rxrpc_poll(struct file *
struct rxrpc_sock *rx = rxrpc_sk(sk);
__poll_t mask;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
mask = 0;

/* the socket is readable if there are any messages waiting on the Rx
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1543,7 +1543,7 @@ static __poll_t smc_poll(struct file *fi
mask |= EPOLLERR;
} else {
if (sk->sk_state != SMC_CLOSED)
- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
if (sk->sk_err)
mask |= EPOLLERR;
if ((sk->sk_shutdown == SHUTDOWN_MASK) ||
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -715,7 +715,7 @@ static __poll_t tipc_poll(struct file *f
struct tipc_sock *tsk = tipc_sk(sk);
__poll_t revents = 0;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);

if (sk->sk_shutdown & RCV_SHUTDOWN)
revents |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2640,7 +2640,7 @@ static __poll_t unix_poll(struct file *f
struct sock *sk = sock->sk;
__poll_t mask;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
mask = 0;

/* exceptional events? */
@@ -2677,7 +2677,7 @@ static __poll_t unix_dgram_poll(struct f
unsigned int writable;
__poll_t mask;

- sock_poll_wait(file, wait);
+ sock_poll_wait(file, sock, wait);
mask = 0;

/* exceptional events? */

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