From patchwork Fri Oct 13 16:03:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13421277 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 46F68CDB482 for ; Fri, 13 Oct 2023 16:06:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232840AbjJMQGf (ORCPT ); Fri, 13 Oct 2023 12:06:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232860AbjJMQGI (ORCPT ); Fri, 13 Oct 2023 12:06:08 -0400 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 2DB62139 for ; Fri, 13 Oct 2023 09:05:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1697213108; 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=ntUQ/reWYDAgg2miRGVf+hR8qevYgo6i7or36auU25I=; b=SF/m7ZQQs7yp9sAUKawbm3bMQ0lGHkCQEo5/E0YBQFoLryNVNU/IJIoLUseXF6WFa2M2QL knUeGx1562wxPo6DEXXf3T6IBMzh9ALu/MBmAKbpXOYZzMghXh/gTwLrRHNYHqsMUMrJ3G dH07IvGsEVPX1zgym3Q+Urj+O5no0A8= Received: from mimecast-mx02.redhat.com (mx-ext.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-681--Tly13tIP_OoFZmS3aBALw-1; Fri, 13 Oct 2023 12:05:05 -0400 X-MC-Unique: -Tly13tIP_OoFZmS3aBALw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6FBB83C40C20; Fri, 13 Oct 2023 16:05:04 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id E4F5C1C06535; Fri, 13 Oct 2023 16:05:01 +0000 (UTC) From: David Howells To: Jeff Layton , Steve French Cc: David Howells , Matthew Wilcox , Marc Dionne , Paulo Alcantara , Shyam Prasad N , Tom Talpey , Dominique Martinet , Ilya Dryomov , Christian Brauner , linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-cachefs@redhat.com Subject: [RFC PATCH 11/53] netfs: Add support for DIO buffering Date: Fri, 13 Oct 2023 17:03:40 +0100 Message-ID: <20231013160423.2218093-12-dhowells@redhat.com> In-Reply-To: <20231013160423.2218093-1-dhowells@redhat.com> References: <20231013160423.2218093-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Add a bvec array pointer and an iterator to netfs_io_request for either holding a copy of a DIO iterator or a list of all the bits of buffer pointed to by a DIO iterator. There are two problems: Firstly, if an iovec-class iov_iter is passed to ->read_iter() or ->write_iter(), this cannot be passed directly to kernel_sendmsg() or kernel_recvmsg() as that may cause locking recursion if a fault is generated, so we need to keep track of the pages involved separately. Secondly, if the I/O is asynchronous, we must copy the iov_iter describing the buffer before returning to the caller as it may be immediately deallocated. Signed-off-by: David Howells cc: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/objects.c | 10 ++++++++++ include/linux/netfs.h | 3 +++ 2 files changed, 13 insertions(+) diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c index 8e92b8401aaa..4396318081bf 100644 --- a/fs/netfs/objects.c +++ b/fs/netfs/objects.c @@ -78,6 +78,7 @@ static void netfs_free_request(struct work_struct *work) { struct netfs_io_request *rreq = container_of(work, struct netfs_io_request, work); + unsigned int i; trace_netfs_rreq(rreq, netfs_rreq_trace_free); netfs_proc_del_rreq(rreq); @@ -86,6 +87,15 @@ static void netfs_free_request(struct work_struct *work) rreq->netfs_ops->free_request(rreq); if (rreq->cache_resources.ops) rreq->cache_resources.ops->end_operation(&rreq->cache_resources); + if (rreq->direct_bv) { + for (i = 0; i < rreq->direct_bv_count; i++) { + if (rreq->direct_bv[i].bv_page) { + if (rreq->direct_bv_unpin) + unpin_user_page(rreq->direct_bv[i].bv_page); + } + } + kvfree(rreq->direct_bv); + } kfree_rcu(rreq, rcu); netfs_stat_d(&netfs_n_rh_rreq); } diff --git a/include/linux/netfs.h b/include/linux/netfs.h index bd0437088f0e..66479a61ad00 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -191,7 +191,9 @@ struct netfs_io_request { struct list_head subrequests; /* Contributory I/O operations */ struct iov_iter iter; /* Unencrypted-side iterator */ struct iov_iter io_iter; /* I/O (Encrypted-side) iterator */ + struct bio_vec *direct_bv; /* DIO buffer list (when handling iovec-iter) */ void *netfs_priv; /* Private data for the netfs */ + unsigned int direct_bv_count; /* Number of elements in bv[] */ unsigned int debug_id; unsigned int rsize; /* Maximum read size (0 for none) */ atomic_t nr_outstanding; /* Number of ops in progress */ @@ -200,6 +202,7 @@ struct netfs_io_request { size_t len; /* Length of the request */ short error; /* 0 or error that occurred */ enum netfs_io_origin origin; /* Origin of the request */ + bool direct_bv_unpin; /* T if direct_bv[] must be unpinned */ loff_t i_size; /* Size of the file */ loff_t start; /* Start position */ pgoff_t no_unlock_folio; /* Don't unlock this folio after read */