From patchwork Wed Jan 25 21:45:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13116305 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 25B22C54E94 for ; Wed, 25 Jan 2023 21:47:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236147AbjAYVrt (ORCPT ); Wed, 25 Jan 2023 16:47:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236356AbjAYVre (ORCPT ); Wed, 25 Jan 2023 16:47:34 -0500 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 0AEAD5CE60 for ; Wed, 25 Jan 2023 13:46:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674683178; 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=lFNFB5o9hIqypPIx6Vklcw5xd9odjnjhSbsuxZfyh1E=; b=R2paPiCkFWfryQqo8zpskeeFjr5wzTJQPFHN22D/C0V4g9gOzRdDNl+mpoIxadxPmHZQF1 jeMLs4GGchNsBz7le7KXJDY3VWiY23vbnNlTLH6MhBLN2dTVu8QX+cIynjTuP93AFy7tAz HfbRZVox7ApG4MIQByc2jY4VCKwdwmk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-182-VEP3o4fkOeKuedE9PRErFg-1; Wed, 25 Jan 2023 16:46:14 -0500 X-MC-Unique: VEP3o4fkOeKuedE9PRErFg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1A5C1857F44; Wed, 25 Jan 2023 21:46:14 +0000 (UTC) Received: from warthog.procyon.org.uk.com (unknown [10.33.36.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1E83F1400AFC; Wed, 25 Jan 2023 21:46:12 +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, Steve French , linux-rdma@vger.kernel.org Subject: [RFC 10/13] cifs: Build the RDMA SGE list directly from an iterator Date: Wed, 25 Jan 2023 21:45:40 +0000 Message-Id: <20230125214543.2337639-11-dhowells@redhat.com> In-Reply-To: <20230125214543.2337639-1-dhowells@redhat.com> References: <20230125214543.2337639-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 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 cc: Steve French cc: Shyam Prasad N cc: Rohith Surabattula cc: Tom Talpey cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: linux-rdma@vger.kernel.org Link: https://lore.kernel.org/r/166697260361.61150.5064013393408112197.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/166732032518.3186319.1859601819981624629.stgit@warthog.procyon.org.uk/ # rfc --- fs/cifs/smbdirect.c | 163 +++++++++++++++++--------------------------- fs/cifs/smbdirect.h | 3 +- 2 files changed, 65 insertions(+), 101 deletions(-) diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c index 7f0a9a8ce9f7..fad75c5ac5b8 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); } /* @@ -1933,42 +1941,6 @@ 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; - - /* We're not expecting a user-backed iter */ - WARN_ON(iov_iter_extract_will_pin(iter)); - - 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), 0); - 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 @@ -2129,10 +2101,10 @@ static void destroy_mr_list(struct smbd_connection *info) cancel_work_sync(&info->mr_recovery_work); list_for_each_entry_safe(mr, tmp, &info->mr_list, list) { if (mr->state == MR_INVALIDATED) - ib_dma_unmap_sg(info->id->device, mr->sgl, - mr->sgl_count, mr->dir); + ib_dma_unmap_sg(info->id->device, mr->sgt.sgl, + mr->sgt.nents, mr->dir); ib_dereg_mr(mr->mr); - kfree(mr->sgl); + kfree(mr->sgt.sgl); kfree(mr); } } @@ -2167,11 +2139,10 @@ static int allocate_mr_list(struct smbd_connection *info) info->mr_type, info->max_frmr_depth); goto out; } - smbdirect_mr->sgl = kcalloc( - info->max_frmr_depth, - sizeof(struct scatterlist), - GFP_KERNEL); - if (!smbdirect_mr->sgl) { + smbdirect_mr->sgt.sgl = kcalloc(info->max_frmr_depth, + sizeof(struct scatterlist), + GFP_KERNEL); + if (!smbdirect_mr->sgt.sgl) { log_rdma_mr(ERR, "failed to allocate sgl\n"); ib_dereg_mr(smbdirect_mr->mr); goto out; @@ -2190,7 +2161,7 @@ static int allocate_mr_list(struct smbd_connection *info) list_for_each_entry_safe(smbdirect_mr, tmp, &info->mr_list, list) { ib_dereg_mr(smbdirect_mr->mr); - kfree(smbdirect_mr->sgl); + kfree(smbdirect_mr->sgt.sgl); kfree(smbdirect_mr); } return -ENOMEM; @@ -2244,22 +2215,20 @@ static struct smbd_mr *get_mr(struct smbd_connection *info) /* * Transcribe the pages from an iterator into an MR scatterlist. - * @iter: The iterator to transcribe - * @_remaining_data_length: remaining data to send in this payload */ static int smbd_iter_to_mr(struct smbd_connection *info, struct iov_iter *iter, - struct scatterlist *sgl, - unsigned int num_pages) + struct sg_table *sgt, + unsigned int max_sg) { - struct sg_table sgtable = { .sgl = sgl }; int ret; - sg_init_table(sgl, num_pages); + memset(sgt->sgl, 0, max_sg * sizeof(struct scatterlist)); - ret = netfs_extract_iter_to_sg(iter, iov_iter_count(iter), - &sgtable, num_pages, 0); + ret = netfs_extract_iter_to_sg(iter, iov_iter_count(iter), sgt, max_sg, 0); WARN_ON(ret < 0); + if (sgt->nents > 0) + sg_mark_end(&sgt->sgl[sgt->nents - 1]); return ret; } @@ -2296,25 +2265,27 @@ struct smbd_mr *smbd_register_mr(struct smbd_connection *info, dir = writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE; smbdirect_mr->dir = dir; smbdirect_mr->need_invalidate = need_invalidate; - smbdirect_mr->sgl_count = num_pages; + smbdirect_mr->sgt.nents = 0; + smbdirect_mr->sgt.orig_nents = 0; - log_rdma_mr(INFO, "num_pages=0x%x count=0x%zx\n", - num_pages, iov_iter_count(iter)); - smbd_iter_to_mr(info, iter, smbdirect_mr->sgl, num_pages); + log_rdma_mr(INFO, "num_pages=0x%x count=0x%zx depth=%u\n", + num_pages, iov_iter_count(iter), info->max_frmr_depth); + smbd_iter_to_mr(info, iter, &smbdirect_mr->sgt, info->max_frmr_depth); - rc = ib_dma_map_sg(info->id->device, smbdirect_mr->sgl, num_pages, dir); + rc = ib_dma_map_sg(info->id->device, smbdirect_mr->sgt.sgl, + smbdirect_mr->sgt.nents, dir); if (!rc) { log_rdma_mr(ERR, "ib_dma_map_sg num_pages=%x dir=%x rc=%x\n", num_pages, dir, rc); goto dma_map_error; } - rc = ib_map_mr_sg(smbdirect_mr->mr, smbdirect_mr->sgl, num_pages, - NULL, PAGE_SIZE); - if (rc != num_pages) { + rc = ib_map_mr_sg(smbdirect_mr->mr, smbdirect_mr->sgt.sgl, + smbdirect_mr->sgt.nents, NULL, PAGE_SIZE); + if (rc != smbdirect_mr->sgt.nents) { log_rdma_mr(ERR, - "ib_map_mr_sg failed rc = %d num_pages = %x\n", - rc, num_pages); + "ib_map_mr_sg failed rc = %d nents = %x\n", + rc, smbdirect_mr->sgt.nents); goto map_mr_error; } @@ -2346,8 +2317,8 @@ struct smbd_mr *smbd_register_mr(struct smbd_connection *info, /* If all failed, attempt to recover this MR by setting it MR_ERROR*/ map_mr_error: - ib_dma_unmap_sg(info->id->device, smbdirect_mr->sgl, - smbdirect_mr->sgl_count, smbdirect_mr->dir); + ib_dma_unmap_sg(info->id->device, smbdirect_mr->sgt.sgl, + smbdirect_mr->sgt.nents, smbdirect_mr->dir); dma_map_error: smbdirect_mr->state = MR_ERROR; @@ -2414,8 +2385,8 @@ int smbd_deregister_mr(struct smbd_mr *smbdirect_mr) if (smbdirect_mr->state == MR_INVALIDATED) { ib_dma_unmap_sg( - info->id->device, smbdirect_mr->sgl, - smbdirect_mr->sgl_count, + info->id->device, smbdirect_mr->sgt.sgl, + smbdirect_mr->sgt.nents, smbdirect_mr->dir); smbdirect_mr->state = MR_READY; if (atomic_inc_return(&info->mr_ready_count) == 1) @@ -2607,13 +2578,6 @@ static ssize_t smb_extract_iter_to_rdma(struct iov_iter *iter, size_t len, ssize_t ret; int before = rdma->nr_sge; - if (iov_iter_is_discard(iter) || - iov_iter_is_pipe(iter) || - user_backed_iter(iter)) { - WARN_ON_ONCE(1); - return -EIO; - } - switch (iov_iter_type(iter)) { case ITER_BVEC: ret = smb_extract_bvec_to_rdma(iter, rdma, len); @@ -2625,7 +2589,8 @@ static ssize_t smb_extract_iter_to_rdma(struct iov_iter *iter, size_t len, ret = smb_extract_xarray_to_rdma(iter, rdma, len); break; default: - BUG(); + WARN_ON_ONCE(1); + return -EIO; } if (ret > 0) { diff --git a/fs/cifs/smbdirect.h b/fs/cifs/smbdirect.h index be2cf18b7fec..83f239f376f0 100644 --- a/fs/cifs/smbdirect.h +++ b/fs/cifs/smbdirect.h @@ -288,8 +288,7 @@ struct smbd_mr { struct list_head list; enum mr_state state; struct ib_mr *mr; - struct scatterlist *sgl; - int sgl_count; + struct sg_table sgt; enum dma_data_direction dir; union { struct ib_reg_wr wr;