cifs: add ability to send an echo request

[firefly-linux-kernel-4.4.55.git] / fs / cifs / cifssmb.c

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 3652cc60314ceea3f19ac3ec1714e93b94b85433..54b9f5d8d1dbf94a422d212039b45ea3862c5098 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -706,6 +706,53 @@ CIFSSMBTDis(const int xid, struct cifsTconInfo *tcon)
        return rc;
 }
 
+/*
+ * This is a no-op for now. We're not really interested in the reply, but
+ * rather in the fact that the server sent one and that server->lstrp
+ * gets updated.
+ *
+ * FIXME: maybe we should consider checking that the reply matches request?
+ */
+static void
+cifs_echo_callback(struct mid_q_entry *mid)
+{
+       struct TCP_Server_Info *server = mid->callback_data;
+
+       DeleteMidQEntry(mid);
+       atomic_dec(&server->inFlight);
+       wake_up(&server->request_q);
+}
+
+int
+CIFSSMBEcho(struct TCP_Server_Info *server)
+{
+       ECHO_REQ *smb;
+       int rc = 0;
+
+       cFYI(1, "In echo request");
+
+       rc = small_smb_init(SMB_COM_ECHO, 0, NULL, (void **)&smb);
+       if (rc)
+               return rc;
+
+       /* set up echo request */
+       smb->hdr.Tid = cpu_to_le16(0xffff);
+       smb->hdr.WordCount = cpu_to_le16(1);
+       smb->EchoCount = cpu_to_le16(1);
+       smb->ByteCount = cpu_to_le16(1);
+       smb->Data[0] = 'a';
+       smb->hdr.smb_buf_length += 3;
+
+       rc = cifs_call_async(server, (struct smb_hdr *)smb,
+                               cifs_echo_callback, server);
+       if (rc)
+               cFYI(1, "Echo request failed: %d", rc);
+
+       cifs_small_buf_release(smb);
+
+       return rc;
+}
+
 int
 CIFSSMBLogoff(const int xid, struct cifsSesInfo *ses)
 {