diff options
author | gVisor bot <gvisor-bot@google.com> | 2019-09-13 00:47:41 +0000 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2019-09-13 00:47:41 +0000 |
commit | c65b5a8d44c27127001097108af9032ad6bb4286 (patch) | |
tree | 4dea9b46753220163901cf3b6e591d18fa7bf46c /pkg/tcpip/transport/tcp | |
parent | 0c071bcbb200129890af02123fb3eaf117303172 (diff) | |
parent | 7c6ab6a219f37a1d4c18ced4a602458fcf363f85 (diff) |
Merge release-20190806.1-142-g7c6ab6a (automated)
Diffstat (limited to 'pkg/tcpip/transport/tcp')
-rw-r--r-- | pkg/tcpip/transport/tcp/endpoint.go | 68 |
1 files changed, 37 insertions, 31 deletions
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go index ac927569a..dd931f88c 100644 --- a/pkg/tcpip/transport/tcp/endpoint.go +++ b/pkg/tcpip/transport/tcp/endpoint.go @@ -806,7 +806,7 @@ func (e *endpoint) isEndpointWritableLocked() (int, *tcpip.Error) { } // Write writes data to the endpoint's peer. -func (e *endpoint) Write(p tcpip.Payload, opts tcpip.WriteOptions) (int64, <-chan struct{}, *tcpip.Error) { +func (e *endpoint) Write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-chan struct{}, *tcpip.Error) { // Linux completely ignores any address passed to sendto(2) for TCP sockets // (without the MSG_FASTOPEN flag). Corking is unimplemented, so opts.More // and opts.EndOfRecord are also ignored. @@ -821,47 +821,52 @@ func (e *endpoint) Write(p tcpip.Payload, opts tcpip.WriteOptions) (int64, <-cha return 0, nil, err } - e.sndBufMu.Unlock() - e.mu.RUnlock() - - // Nothing to do if the buffer is empty. - if p.Size() == 0 { - return 0, nil, nil + // We can release locks while copying data. + // + // This is not possible if atomic is set, because we can't allow the + // available buffer space to be consumed by some other caller while we + // are copying data in. + if !opts.Atomic { + e.sndBufMu.Unlock() + e.mu.RUnlock() } - // Copy in memory without holding sndBufMu so that worker goroutine can - // make progress independent of this operation. - v, perr := p.Get(avail) - if perr != nil { + // Fetch data. + v, perr := p.Payload(avail) + if perr != nil || len(v) == 0 { + if opts.Atomic { // See above. + e.sndBufMu.Unlock() + e.mu.RUnlock() + } + // Note that perr may be nil if len(v) == 0. return 0, nil, perr } - e.mu.RLock() - e.sndBufMu.Lock() + if !opts.Atomic { // See above. + e.mu.RLock() + e.sndBufMu.Lock() - // Because we released the lock before copying, check state again - // to make sure the endpoint is still in a valid state for a - // write. - avail, err = e.isEndpointWritableLocked() - if err != nil { - e.sndBufMu.Unlock() - e.mu.RUnlock() - return 0, nil, err - } + // Because we released the lock before copying, check state again + // to make sure the endpoint is still in a valid state for a write. + avail, err = e.isEndpointWritableLocked() + if err != nil { + e.sndBufMu.Unlock() + e.mu.RUnlock() + return 0, nil, err + } - // Discard any excess data copied in due to avail being reduced due to a - // simultaneous write call to the socket. - if avail < len(v) { - v = v[:avail] + // Discard any excess data copied in due to avail being reduced due + // to a simultaneous write call to the socket. + if avail < len(v) { + v = v[:avail] + } } // Add data to the send queue. - l := len(v) s := newSegmentFromView(&e.route, e.id, v) - e.sndBufUsed += l - e.sndBufInQueue += seqnum.Size(l) + e.sndBufUsed += len(v) + e.sndBufInQueue += seqnum.Size(len(v)) e.sndQueue.PushBack(s) - e.sndBufMu.Unlock() // Release the endpoint lock to prevent deadlocks due to lock // order inversion when acquiring workMu. @@ -875,7 +880,8 @@ func (e *endpoint) Write(p tcpip.Payload, opts tcpip.WriteOptions) (int64, <-cha // Let the protocol goroutine do the work. e.sndWaker.Assert() } - return int64(l), nil, nil + + return int64(len(v)), nil, nil } // Peek reads data without consuming it from the endpoint. |