This is a note to let you know that I've just added the patch titled
AF_VSOCK: Shrink the area influenced by prepare_to_wait
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: af_vsock-shrink-the-area-influenced-by-prepare_to_wait.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From f7f9b5e7f8eccfd68ffa7b8d74b07c478bb9e7f0 Mon Sep 17 00:00:00 2001
From: Claudio Imbrenda imbrenda@linux.vnet.ibm.com Date: Tue, 22 Mar 2016 17:05:52 +0100 Subject: AF_VSOCK: Shrink the area influenced by prepare_to_wait
From: Claudio Imbrenda imbrenda@linux.vnet.ibm.com
commit f7f9b5e7f8eccfd68ffa7b8d74b07c478bb9e7f0 upstream.
When a thread is prepared for waiting by calling prepare_to_wait, sleeping is not allowed until either the wait has taken place or finish_wait has been called. The existing code in af_vsock imposed unnecessary no-sleep assumptions to a broad list of backend functions. This patch shrinks the influence of prepare_to_wait to the area where it is strictly needed, therefore relaxing the no-sleep restriction there.
Signed-off-by: Claudio Imbrenda imbrenda@linux.vnet.ibm.com Signed-off-by: David S. Miller davem@davemloft.net Cc: "Jorgen S. Hansen" jhansen@vmware.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/vmw_vsock/af_vsock.c | 158 +++++++++++++++++++++++++---------------------- 1 file changed, 85 insertions(+), 73 deletions(-)
--- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1209,10 +1209,14 @@ static int vsock_stream_connect(struct s
if (signal_pending(current)) { err = sock_intr_errno(timeout); - goto out_wait_error; + sk->sk_state = SS_UNCONNECTED; + sock->state = SS_UNCONNECTED; + goto out_wait; } else if (timeout == 0) { err = -ETIMEDOUT; - goto out_wait_error; + sk->sk_state = SS_UNCONNECTED; + sock->state = SS_UNCONNECTED; + goto out_wait; }
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); @@ -1220,20 +1224,17 @@ static int vsock_stream_connect(struct s
if (sk->sk_err) { err = -sk->sk_err; - goto out_wait_error; - } else + sk->sk_state = SS_UNCONNECTED; + sock->state = SS_UNCONNECTED; + } else { err = 0; + }
out_wait: finish_wait(sk_sleep(sk), &wait); out: release_sock(sk); return err; - -out_wait_error: - sk->sk_state = SS_UNCONNECTED; - sock->state = SS_UNCONNECTED; - goto out_wait; }
static int vsock_accept(struct socket *sock, struct socket *newsock, int flags) @@ -1270,18 +1271,20 @@ static int vsock_accept(struct socket *s listener->sk_err == 0) { release_sock(listener); timeout = schedule_timeout(timeout); + finish_wait(sk_sleep(listener), &wait); lock_sock(listener);
if (signal_pending(current)) { err = sock_intr_errno(timeout); - goto out_wait; + goto out; } else if (timeout == 0) { err = -EAGAIN; - goto out_wait; + goto out; }
prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE); } + finish_wait(sk_sleep(listener), &wait);
if (listener->sk_err) err = -listener->sk_err; @@ -1301,19 +1304,15 @@ static int vsock_accept(struct socket *s */ if (err) { vconnected->rejected = true; - release_sock(connected); - sock_put(connected); - goto out_wait; + } else { + newsock->state = SS_CONNECTED; + sock_graft(connected, newsock); }
- newsock->state = SS_CONNECTED; - sock_graft(connected, newsock); release_sock(connected); sock_put(connected); }
-out_wait: - finish_wait(sk_sleep(listener), &wait); out: release_sock(listener); return err; @@ -1557,11 +1556,11 @@ static int vsock_stream_sendmsg(struct s if (err < 0) goto out;
- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
while (total_written < len) { ssize_t written;
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); while (vsock_stream_has_space(vsk) == 0 && sk->sk_err == 0 && !(sk->sk_shutdown & SEND_SHUTDOWN) && @@ -1570,27 +1569,33 @@ static int vsock_stream_sendmsg(struct s /* Don't wait for non-blocking sockets. */ if (timeout == 0) { err = -EAGAIN; - goto out_wait; + finish_wait(sk_sleep(sk), &wait); + goto out_err; }
err = transport->notify_send_pre_block(vsk, &send_data); - if (err < 0) - goto out_wait; + if (err < 0) { + finish_wait(sk_sleep(sk), &wait); + goto out_err; + }
release_sock(sk); timeout = schedule_timeout(timeout); lock_sock(sk); if (signal_pending(current)) { err = sock_intr_errno(timeout); - goto out_wait; + finish_wait(sk_sleep(sk), &wait); + goto out_err; } else if (timeout == 0) { err = -EAGAIN; - goto out_wait; + finish_wait(sk_sleep(sk), &wait); + goto out_err; }
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); } + finish_wait(sk_sleep(sk), &wait);
/* These checks occur both as part of and after the loop * conditional since we need to check before and after @@ -1598,16 +1603,16 @@ static int vsock_stream_sendmsg(struct s */ if (sk->sk_err) { err = -sk->sk_err; - goto out_wait; + goto out_err; } else if ((sk->sk_shutdown & SEND_SHUTDOWN) || (vsk->peer_shutdown & RCV_SHUTDOWN)) { err = -EPIPE; - goto out_wait; + goto out_err; }
err = transport->notify_send_pre_enqueue(vsk, &send_data); if (err < 0) - goto out_wait; + goto out_err;
/* Note that enqueue will only write as many bytes as are free * in the produce queue, so we don't need to ensure len is @@ -1620,7 +1625,7 @@ static int vsock_stream_sendmsg(struct s len - total_written); if (written < 0) { err = -ENOMEM; - goto out_wait; + goto out_err; }
total_written += written; @@ -1628,14 +1633,13 @@ static int vsock_stream_sendmsg(struct s err = transport->notify_send_post_enqueue( vsk, written, &send_data); if (err < 0) - goto out_wait; + goto out_err;
}
-out_wait: +out_err: if (total_written > 0) err = total_written; - finish_wait(sk_sleep(sk), &wait); out: release_sock(sk); return err; @@ -1716,21 +1720,61 @@ vsock_stream_recvmsg(struct socket *sock if (err < 0) goto out;
- prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
while (1) { - s64 ready = vsock_stream_has_data(vsk); + s64 ready;
- if (ready < 0) { - /* Invalid queue pair content. XXX This should be - * changed to a connection reset in a later change. - */ + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + ready = vsock_stream_has_data(vsk);
- err = -ENOMEM; - goto out_wait; - } else if (ready > 0) { + if (ready == 0) { + if (sk->sk_err != 0 || + (sk->sk_shutdown & RCV_SHUTDOWN) || + (vsk->peer_shutdown & SEND_SHUTDOWN)) { + finish_wait(sk_sleep(sk), &wait); + break; + } + /* Don't wait for non-blocking sockets. */ + if (timeout == 0) { + err = -EAGAIN; + finish_wait(sk_sleep(sk), &wait); + break; + } + + err = transport->notify_recv_pre_block( + vsk, target, &recv_data); + if (err < 0) { + finish_wait(sk_sleep(sk), &wait); + break; + } + release_sock(sk); + timeout = schedule_timeout(timeout); + lock_sock(sk); + + if (signal_pending(current)) { + err = sock_intr_errno(timeout); + finish_wait(sk_sleep(sk), &wait); + break; + } else if (timeout == 0) { + err = -EAGAIN; + finish_wait(sk_sleep(sk), &wait); + break; + } + } else { ssize_t read;
+ finish_wait(sk_sleep(sk), &wait); + + if (ready < 0) { + /* Invalid queue pair content. XXX This should + * be changed to a connection reset in a later + * change. + */ + + err = -ENOMEM; + goto out; + } + err = transport->notify_recv_pre_dequeue( vsk, target, &recv_data); if (err < 0) @@ -1750,42 +1794,12 @@ vsock_stream_recvmsg(struct socket *sock vsk, target, read, !(flags & MSG_PEEK), &recv_data); if (err < 0) - goto out_wait; + goto out;
if (read >= target || flags & MSG_PEEK) break;
target -= read; - } else { - if (sk->sk_err != 0 || (sk->sk_shutdown & RCV_SHUTDOWN) - || (vsk->peer_shutdown & SEND_SHUTDOWN)) { - break; - } - /* Don't wait for non-blocking sockets. */ - if (timeout == 0) { - err = -EAGAIN; - break; - } - - err = transport->notify_recv_pre_block( - vsk, target, &recv_data); - if (err < 0) - break; - - release_sock(sk); - timeout = schedule_timeout(timeout); - lock_sock(sk); - - if (signal_pending(current)) { - err = sock_intr_errno(timeout); - break; - } else if (timeout == 0) { - err = -EAGAIN; - break; - } - - prepare_to_wait(sk_sleep(sk), &wait, - TASK_INTERRUPTIBLE); } }
@@ -1797,8 +1811,6 @@ vsock_stream_recvmsg(struct socket *sock if (copied > 0) err = copied;
-out_wait: - finish_wait(sk_sleep(sk), &wait); out: release_sock(sk); return err;
Patches currently in stable-queue which might be from imbrenda@linux.vnet.ibm.com are
queue-4.4/af_vsock-shrink-the-area-influenced-by-prepare_to_wait.patch queue-4.4/vsock-use-new-wait-api-for-vsock_stream_sendmsg.patch