[PATCH 4.20 065/117] smb3: add credits we receive from oplock/break PDUs

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>

commit 2e5700bdde438ed708b36d8acd0398dc73cbf759 upstream.

Otherwise we gradually leak credits leading to potential
hung session.

Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
CC: Stable <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/cifs/smb2misc.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -648,6 +648,13 @@ smb2_is_valid_oplock_break(char *buffer,
 	if (rsp->sync_hdr.Command != SMB2_OPLOCK_BREAK)
 		return false;
 
+	if (rsp->sync_hdr.CreditRequest) {
+		spin_lock(&server->req_lock);
+		server->credits += le16_to_cpu(rsp->sync_hdr.CreditRequest);
+		spin_unlock(&server->req_lock);
+		wake_up(&server->request_q);
+	}
+
 	if (rsp->StructureSize !=
 				smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
 		if (le16_to_cpu(rsp->StructureSize) == 44)