From patchwork Fri Oct 28 15:56:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13023914 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 84170ECAAA1 for ; Fri, 28 Oct 2022 15:59:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230167AbiJ1P7I (ORCPT ); Fri, 28 Oct 2022 11:59:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229877AbiJ1P5x (ORCPT ); Fri, 28 Oct 2022 11:57:53 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B496213469 for ; Fri, 28 Oct 2022 08:56:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666972610; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nYX9C4tV+uCYpsSIy4eEzmHqt/2Pk0X68HjqPEsanbk=; b=eF7eVBJCQEUKMvwqicZaWYKUkEIMo9Zm+xAiPRlQB8ViyVSO9zcxZ5JjRyvPsvuu7zj2GV U2M2AFn7WqE4JfGPcKvHP/6FML4sUtSxDc++/crxC0hicgGufPzQskMDxGOXEqItJBlF9r 32BxGYr+1cOOml3Xu/oPsV4NpOxiIp4= 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-198-Hfz3-hoFOkeCyx0xKcYQpw-1; Fri, 28 Oct 2022 11:56:46 -0400 X-MC-Unique: Hfz3-hoFOkeCyx0xKcYQpw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9FF2229AA389; Fri, 28 Oct 2022 15:56:45 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.73]) by smtp.corp.redhat.com (Postfix) with ESMTP id 35B0AC15BA8; Fri, 28 Oct 2022 15:56:44 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [RFC PATCH 8/9] cifs: Build the RDMA SGE list directly from an iterator From: David Howells To: Steve French , Al Viro Cc: dhowells@redhat.com, Shyam Prasad N , Rohith Surabattula , Tom Talpey , Christoph Hellwig , Matthew Wilcox , Jeff Layton , linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Fri, 28 Oct 2022 16:56:43 +0100 Message-ID: <166697260361.61150.5064013393408112197.stgit@warthog.procyon.org.uk> In-Reply-To: <166697254399.61150.1256557652599252121.stgit@warthog.procyon.org.uk> References: <166697254399.61150.1256557652599252121.stgit@warthog.procyon.org.uk> User-Agent: StGit/1.5 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org In the depths of the cifs RDMA code, extract part of an iov iterator directly into an SGE list without going through an intermediate scatterlist. Note that this doesn't support extraction from an IOBUF- or UBUF-type iterator (ie. user-supplied buffer). The assumption is that the higher layers will extract those to a BVEC-type iterator first and do whatever is required to stop the pages from going away. Signed-off-by: David Howells --- fs/cifs/smbdirect.c | 89 ++++++++++++++++++--------------------------------- 1 file changed, 32 insertions(+), 57 deletions(-) diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c index 7f1a1e190650..c4465d6a2fc6 100644 --- a/fs/cifs/smbdirect.c +++ b/fs/cifs/smbdirect.c @@ -828,16 +828,16 @@ static int smbd_post_send(struct smbd_connection *info, return rc; } -static int smbd_post_send_sgl(struct smbd_connection *info, - struct scatterlist *sgl, int data_length, int remaining_data_length) +static int smbd_post_send_iter(struct smbd_connection *info, + struct iov_iter *iter, + int *_remaining_data_length) { - int num_sgs; int i, rc; int header_length; + int data_length; struct smbd_request *request; struct smbd_data_transfer *packet; int new_credits; - struct scatterlist *sg; wait_credit: /* Wait for send credits. A SMBD packet needs one credit */ @@ -881,6 +881,30 @@ static int smbd_post_send_sgl(struct smbd_connection *info, } request->info = info; + memset(request->sge, 0, sizeof(request->sge)); + + /* Fill in the data payload to find out how much data we can add */ + if (iter) { + struct smb_extract_to_rdma extract = { + .nr_sge = 1, + .max_sge = SMBDIRECT_MAX_SEND_SGE, + .sge = request->sge, + .device = info->id->device, + .local_dma_lkey = info->pd->local_dma_lkey, + .direction = DMA_TO_DEVICE, + }; + + rc = smb_extract_iter_to_rdma(iter, *_remaining_data_length, + &extract); + if (rc < 0) + goto err_dma; + data_length = rc; + request->num_sge = extract.nr_sge; + *_remaining_data_length -= data_length; + } else { + data_length = 0; + request->num_sge = 1; + } /* Fill in the packet header */ packet = smbd_request_payload(request); @@ -902,7 +926,7 @@ static int smbd_post_send_sgl(struct smbd_connection *info, else packet->data_offset = cpu_to_le32(24); packet->data_length = cpu_to_le32(data_length); - packet->remaining_data_length = cpu_to_le32(remaining_data_length); + packet->remaining_data_length = cpu_to_le32(*_remaining_data_length); packet->padding = 0; log_outgoing(INFO, "credits_requested=%d credits_granted=%d data_offset=%d data_length=%d remaining_data_length=%d\n", @@ -918,7 +942,6 @@ static int smbd_post_send_sgl(struct smbd_connection *info, if (!data_length) header_length = offsetof(struct smbd_data_transfer, padding); - request->num_sge = 1; request->sge[0].addr = ib_dma_map_single(info->id->device, (void *)packet, header_length, @@ -932,23 +955,6 @@ static int smbd_post_send_sgl(struct smbd_connection *info, request->sge[0].length = header_length; request->sge[0].lkey = info->pd->local_dma_lkey; - /* Fill in the packet data payload */ - num_sgs = sgl ? sg_nents(sgl) : 0; - for_each_sg(sgl, sg, num_sgs, i) { - request->sge[i+1].addr = - ib_dma_map_page(info->id->device, sg_page(sg), - sg->offset, sg->length, DMA_TO_DEVICE); - if (ib_dma_mapping_error( - info->id->device, request->sge[i+1].addr)) { - rc = -EIO; - request->sge[i+1].addr = 0; - goto err_dma; - } - request->sge[i+1].length = sg->length; - request->sge[i+1].lkey = info->pd->local_dma_lkey; - request->num_sge++; - } - rc = smbd_post_send(info, request); if (!rc) return 0; @@ -987,8 +993,10 @@ static int smbd_post_send_sgl(struct smbd_connection *info, */ static int smbd_post_send_empty(struct smbd_connection *info) { + int remaining_data_length = 0; + info->count_send_empty++; - return smbd_post_send_sgl(info, NULL, 0, 0); + return smbd_post_send_iter(info, NULL, &remaining_data_length); } /* @@ -1932,39 +1940,6 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg) return rc; } -/* - * Send the contents of an iterator - * @iter: The iterator to send - * @_remaining_data_length: remaining data to send in this payload - */ -static int smbd_post_send_iter(struct smbd_connection *info, - struct iov_iter *iter, - int *_remaining_data_length) -{ - struct scatterlist sgl[SMBDIRECT_MAX_SEND_SGE - 1]; - unsigned int max_payload = info->max_send_size - sizeof(struct smbd_data_transfer); - ssize_t rc; - - do { - struct sg_table sgtable = { .sgl = sgl }; - size_t maxlen = min_t(size_t, *_remaining_data_length, max_payload); - - sg_init_table(sgtable.sgl, ARRAY_SIZE(sgl)); - rc = netfs_extract_iter_to_sg(iter, maxlen, - &sgtable, ARRAY_SIZE(sgl)); - if (rc < 0) - break; - if (WARN_ON_ONCE(sgtable.nents == 0)) - return -EIO; - - sg_mark_end(&sgl[sgtable.nents - 1]); - *_remaining_data_length -= rc; - rc = smbd_post_send_sgl(info, sgl, rc, *_remaining_data_length); - } while (rc == 0 && iov_iter_count(iter) > 0); - - return rc; -} - /* * Send data to transport * Each rqst is transported as a SMBDirect payload