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Thu, 7 Dec 2023 21:22:52 +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 v3 13/59] netfs: Add support for DIO buffering Date: Thu, 7 Dec 2023 21:21:20 +0000 Message-ID: <20231207212206.1379128-14-dhowells@redhat.com> In-Reply-To: <20231207212206.1379128-1-dhowells@redhat.com> References: <20231207212206.1379128-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 X-Rspamd-Queue-Id: E30084001C X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: ydwx4xr4yx4pbxypqepp85ku9wayo5ge X-HE-Tag: 1701984187-192979 X-HE-Meta: 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 y6LNzVza /ViZRgUzZlAZxx34Btbp2bF3Pu9EaUtGjWHJuEW4Syjp5D7z9B7sZoMlnrkeFqxOgjtsEnWJimiybAhp34aBCuado4o0tIsVATPLGEeW1Hy0UfEWnU8g/RQMqqZVksrLwc/+z9RG+u9Drybg9Y9YxpqNZgpyRhMKu9nlUw6bcZ0cZULdmA5rVKrwAfbhr8oR28GxmH4fACixrEceaHJlkrgT3Tk4tAYv98rzClpSXk6zkKeFV1KT7fbxD0VRcbPvDz0q0hcJ1Crk64oNo+CcJkxg+5wDNtFMu7KAGyqmu2dxLjGc= 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 */