3 files changed, 5 insertions, 42 deletions

diff --git a/pkg/sentry/socket/netstack/BUILD b/pkg/sentry/socket/netstack/BUILD
index b2206900b..22abca120 100644
--- a/pkg/sentry/socket/netstack/BUILD
+++ b/pkg/sentry/socket/netstack/BUILD
@@ -18,7 +18,6 @@ go_library(
     ],
     deps = [
         "//pkg/abi/linux",
-        "//pkg/amutex",
         "//pkg/binary",
         "//pkg/context",
         "//pkg/log",
diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 57f224120..94fb425b2 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -36,7 +36,6 @@ import (
 
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/amutex"
 	"gvisor.dev/gvisor/pkg/binary"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/log"
@@ -459,18 +458,10 @@ func (i *ioSequencePayload) DropFirst(n int) {
 // Write implements fs.FileOperations.Write.
 func (s *SocketOperations) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, _ int64) (int64, error) {
 	f := &ioSequencePayload{ctx: ctx, src: src}
-	n, resCh, err := s.Endpoint.Write(f, tcpip.WriteOptions{})
+	n, err := s.Endpoint.Write(f, tcpip.WriteOptions{})
 	if err == tcpip.ErrWouldBlock {
 		return 0, syserror.ErrWouldBlock
 	}
-
-	if resCh != nil {
-		if err := amutex.Block(ctx, resCh); err != nil {
-			return 0, err
-		}
-		n, _, err = s.Endpoint.Write(f, tcpip.WriteOptions{})
-	}
-
 	if err != nil {
 		return 0, syserr.TranslateNetstackError(err).ToError()
 	}
@@ -526,24 +517,12 @@ func (r *readerPayload) Payload(size int) ([]byte, *tcpip.Error) {
 // ReadFrom implements fs.FileOperations.ReadFrom.
 func (s *SocketOperations) ReadFrom(ctx context.Context, _ *fs.File, r io.Reader, count int64) (int64, error) {
 	f := &readerPayload{ctx: ctx, r: r, count: count}
-	n, resCh, err := s.Endpoint.Write(f, tcpip.WriteOptions{
+	n, err := s.Endpoint.Write(f, tcpip.WriteOptions{
 		// Reads may be destructive but should be very fast,
 		// so we can't release the lock while copying data.
 		Atomic: true,
 	})
 	if err == tcpip.ErrWouldBlock {
-		return 0, syserror.ErrWouldBlock
-	}
-
-	if resCh != nil {
-		if err := amutex.Block(ctx, resCh); err != nil {
-			return 0, err
-		}
-		n, _, err = s.Endpoint.Write(f, tcpip.WriteOptions{
-			Atomic: true, // See above.
-		})
-	}
-	if err == tcpip.ErrWouldBlock {
 		return n, syserror.ErrWouldBlock
 	} else if err != nil {
 		return int64(n), f.err // Propagate error.
@@ -2836,13 +2815,7 @@ func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []b
 	}
 
 	v := &ioSequencePayload{t, src}
-	n, resCh, err := s.Endpoint.Write(v, opts)
-	if resCh != nil {
-		if err := t.Block(resCh); err != nil {
-			return 0, syserr.FromError(err)
-		}
-		n, _, err = s.Endpoint.Write(v, opts)
-	}
+	n, err := s.Endpoint.Write(v, opts)
 	dontWait := flags&linux.MSG_DONTWAIT != 0
 	if err == nil && (n >= v.src.NumBytes() || dontWait) {
 		// Complete write.
@@ -2861,7 +2834,7 @@ func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []b
 	v.DropFirst(int(n))
 	total := n
 	for {
-		n, _, err = s.Endpoint.Write(v, opts)
+		n, err = s.Endpoint.Write(v, opts)
 		v.DropFirst(int(n))
 		total += n
 
diff --git a/pkg/sentry/socket/netstack/netstack_vfs2.go b/pkg/sentry/socket/netstack/netstack_vfs2.go
index b756bfca0..6f70b02fc 100644
--- a/pkg/sentry/socket/netstack/netstack_vfs2.go
+++ b/pkg/sentry/socket/netstack/netstack_vfs2.go
@@ -16,7 +16,6 @@ package netstack
 
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/amutex"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/marshal"
 	"gvisor.dev/gvisor/pkg/marshal/primitive"
@@ -131,18 +130,10 @@ func (s *SocketVFS2) Write(ctx context.Context, src usermem.IOSequence, opts vfs
 	}
 
 	f := &ioSequencePayload{ctx: ctx, src: src}
-	n, resCh, err := s.Endpoint.Write(f, tcpip.WriteOptions{})
+	n, err := s.Endpoint.Write(f, tcpip.WriteOptions{})
 	if err == tcpip.ErrWouldBlock {
 		return 0, syserror.ErrWouldBlock
 	}
-
-	if resCh != nil {
-		if err := amutex.Block(ctx, resCh); err != nil {
-			return 0, err
-		}
-		n, _, err = s.Endpoint.Write(f, tcpip.WriteOptions{})
-	}
-
 	if err != nil {
 		return 0, syserr.TranslateNetstackError(err).ToError()
 	}