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Wed, 13 Dec 2023 15:24:47 +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 , Eric Van Hensbergen , Ilya Dryomov , Christian Brauner , linux-cachefs@redhat.com, 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 Subject: [PATCH v4 13/39] netfs: Add support for DIO buffering Date: Wed, 13 Dec 2023 15:23:23 +0000 Message-ID: <20231213152350.431591-14-dhowells@redhat.com> In-Reply-To: <20231213152350.431591-1-dhowells@redhat.com> References: <20231213152350.431591-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 5A7BC1C0009 X-Stat-Signature: 3xk6ckgjg5e7f8eur193dxb9pmyp4hzb X-Rspam-User: X-HE-Tag: 1702481097-960492 X-HE-Meta: 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 H+Dm1ERv QmUisOaBkSvI27M/zLpg3X/uRSECdIp3p3wTwbkJWlzz9GvjS8xi8qcAMzYczgoLfmxfxQtWqYbU4Mau/lB/5n4DCGctBe+1sm/EpP6OJdfCuCoFjehG6ZFhmkDldm69SozzwJVjM7ES4+9asXgohjW41ffVUR8mGpDSSWfi9zgMH4IHU03LzSMn52mBqFSgkuxrd/clU82mgh/Czu00pwX09MDOdATSCjgf4qTplEnrW9xIgKdiBABKi5uJDAd863MnzwGRH475Oxwd+ltjHhnVOiu1RyNKvEk54yR4ehPsdK6Q= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 | 4 ++++ 2 files changed, 14 insertions(+) diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c index 1bd20bdad983..4df5e5eeada6 100644 --- a/fs/netfs/objects.c +++ b/fs/netfs/objects.c @@ -76,6 +76,7 @@ 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); @@ -84,6 +85,15 @@ 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 3da962e977f5..bbb33ccbf719 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -190,6 +190,9 @@ struct netfs_io_request { struct iov_iter iter; /* Unencrypted-side iterator */ struct iov_iter io_iter; /* I/O (Encrypted-side) iterator */ void *netfs_priv; /* Private data for the netfs */ + struct bio_vec *direct_bv /* DIO buffer list (when handling iovec-iter) */ + __counted_by(direct_bv_count); + unsigned int direct_bv_count; /* Number of elements in direct_bv[] */ unsigned int debug_id; atomic_t nr_outstanding; /* Number of ops in progress */ atomic_t nr_copy_ops; /* Number of copy-to-cache ops in progress */ @@ -197,6 +200,7 @@ 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 */