From nobody Sun Sep 14 08:41:54 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85C8DC54EED for ; Wed, 25 Jan 2023 21:49:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236570AbjAYVte (ORCPT ); Wed, 25 Jan 2023 16:49:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236666AbjAYVsU (ORCPT ); Wed, 25 Jan 2023 16:48:20 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3117F5D91E for ; Wed, 25 Jan 2023 13:46:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674683182; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TREYAwJageIukWTSjR1QmDBqozeTGEzkTCcOqfCkCRk=; b=AWzMt7RF/14YROnIKj/cY2DoUzkC/JGcAHOtKdojKE2iITzdCBEs9+9l9byyZdctfLqD4Z s90wJGBuFAZpTIG0O7VsB/yt9OzAHPJ9qGB/JR851lQkvuRvtL/EYJ/nFSNtPueK2krhIz 3z9xOFR3ctumHMFnJDZc/G+BFIhKKWo= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-567-bwc2LBG4PqONbHKjuCviSw-1; Wed, 25 Jan 2023 16:46:20 -0500 X-MC-Unique: bwc2LBG4PqONbHKjuCviSw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5237A38041D7; Wed, 25 Jan 2023 21:46:19 +0000 (UTC) Received: from warthog.procyon.org.uk.com (unknown [10.33.36.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7343B1121330; Wed, 25 Jan 2023 21:46:17 +0000 (UTC) From: David Howells To: Steve French Cc: David Howells , Al Viro , Shyam Prasad N , Rohith Surabattula , Tom Talpey , Stefan Metzmacher , Christoph Hellwig , Matthew Wilcox , Jeff Layton , linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Long Li , Namjae Jeon Subject: [RFC 12/13] cifs: Fix problem with encrypted RDMA data read Date: Wed, 25 Jan 2023 21:45:42 +0000 Message-Id: <20230125214543.2337639-13-dhowells@redhat.com> In-Reply-To: <20230125214543.2337639-1-dhowells@redhat.com> References: <20230125214543.2337639-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When the cifs client is talking to the ksmbd server by RDMA and the ksmbd server has "smb3 encryption =3D yes" in its config file, the normal PDU stream is encrypted, but the directly-delivered data isn't in the stream (and isn't encrypted), but is rather delivered by DDP/RDMA packets (at least with IWarp). Currently, the direct delivery fails with: buf can not contain only a part of read data WARNING: CPU: 0 PID: 4619 at fs/cifs/smb2ops.c:4731 handle_read_data+0x3= 93/0x405 ... RIP: 0010:handle_read_data+0x393/0x405 ... smb3_handle_read_data+0x30/0x37 receive_encrypted_standard+0x141/0x224 cifs_demultiplex_thread+0x21a/0x63b kthread+0xe7/0xef ret_from_fork+0x22/0x30 The problem apparently stemming from the fact that it's trying to manage the decryption, but the data isn't in the smallbuf, the bigbuf or the page array). This can be fixed simply by inserting an extra case into handle_read_data() that checks to see if use_rdma_mr is true, and if it is, just setting rdata->got_bytes to the length of data delivered and allowing normal continuation. This can be seen in an IWarp packet trace. With the upstream code, it does a DDP/RDMA packet, which produces the warning above and then retries, retrieving the data inline, spread across several SMBDirect messages that get glued together into a single PDU. With the patch applied, only the DDP/RDMA packet is seen. Note that this doesn't happen if the server isn't told to encrypt stuff and it does also happen with softRoCE. Signed-off-by: David Howells cc: Steve French cc: Tom Talpey cc: Long Li cc: Namjae Jeon cc: Stefan Metzmacher cc: linux-cifs@vger.kernel.org Link: https://lore.kernel.org/r/166855224228.1998592.2212551359609792175.st= git@warthog.procyon.org.uk/ # v1 --- fs/cifs/smb2ops.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 335080893ebc..aba6643e0869 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -4721,6 +4721,9 @@ handle_read_data(struct TCP_Server_Info *server, stru= ct mid_q_entry *mid, if (length < 0) return length; rdata->got_bytes =3D data_len; + } else if (use_rdma_mr) { + /* The data was delivered directly by RDMA. */ + rdata->got_bytes =3D data_len; } else { /* read response payload cannot be in both buf and pages */ WARN_ONCE(1, "buf can not contain only a part of read data");