8358496: Concurrent reading from Socket with timeout executes sequentially

Reviewed-by: dfuchs

Author: Alan Bateman

src/java.base/share/classes/sun/nio/ch/NioSocketImpl.java

@@ -288,19 +288,18 @@ private int timedRead(FileDescriptor fd, byte[] b, int off, int len, long nanos)
      * @throws SocketException if the socket is closed or a socket I/O error occurs
      * @throws SocketTimeoutException if the read timeout elapses
      */
-    private int implRead(byte[] b, int off, int len) throws IOException {
+    private int implRead(byte[] b, int off, int len, long remainingNanos) throws IOException {
         int n = 0;
         FileDescriptor fd = beginRead();
         try {
             if (connectionReset)
                 throw new SocketException("Connection reset");
             if (isInputClosed)
                 return -1;
-            int timeout = this.timeout;
-            configureNonBlockingIfNeeded(fd, timeout > 0);
-            if (timeout > 0) {
+            configureNonBlockingIfNeeded(fd, remainingNanos > 0);
+            if (remainingNanos > 0) {
                 // read with timeout
-                n = timedRead(fd, b, off, len, MILLISECONDS.toNanos(timeout));
+                n = timedRead(fd, b, off, len, remainingNanos);
             } else {
                 // read, no timeout
                 n = tryRead(fd, b, off, len);
@@ -335,14 +334,24 @@ private int read(byte[] b, int off, int len) throws IOException {
         if (len == 0) {
             return 0;
         } else {
-            readLock.lock();
+            long remainingNanos = 0;
+            int timeout = this.timeout;
+            if (timeout > 0) {
+                remainingNanos = tryLock(readLock, timeout, MILLISECONDS);
+                if (remainingNanos <= 0) {
+                    assert !readLock.isHeldByCurrentThread();
+                    throw new SocketTimeoutException("Read timed out");
+                }
+            } else {
+                readLock.lock();
+            }
             try {
                 // emulate legacy behavior to return -1, even if socket is closed
                 if (readEOF)
                     return -1;
                 // read up to MAX_BUFFER_SIZE bytes
                 int size = Math.min(len, MAX_BUFFER_SIZE);
-                int n = implRead(b, off, size);
+                int n = implRead(b, off, size, remainingNanos);
                 if (n == -1)
                     readEOF = true;
                 return n;