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Thu, 21 Dec 2023 13:24:59 +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 v5 15/40] netfs: Add support for DIO buffering Date: Thu, 21 Dec 2023 13:23:10 +0000 Message-ID: <20231221132400.1601991-16-dhowells@redhat.com> In-Reply-To: <20231221132400.1601991-1-dhowells@redhat.com> References: <20231221132400.1601991-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 X-Rspamd-Queue-Id: 16BA7140016 X-Rspam-User: X-Stat-Signature: gotcb8nqst5deswcx7s1yiowp3im7oi3 X-Rspamd-Server: rspam01 X-HE-Tag: 1703165105-182225 X-HE-Meta: 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 wFQ420BT diYGoRx8/MxkyKWl2T70kx1cVKvUNheTnPP5PBJJgMaE2EPTvT2SvBVaW3yVs5QsJKrWVBLwwFiw8E+WFymEruoLf3Xj29dzb1/YstG366avIAH5p9+f07Q1Ka4nz+KSA0AJyOMtC8iyTF+pPr4Z4KTf4MQiqvUfA5aUlYnKfU+Qb9XuE0neG6rYrbva1DwgQR75yiZlFw6RwAz/2Uenlm1NtlVNEI2ypikvod33ct5bQjR8MVIoce4Tb9E6vGcGtlXdtD1DO5KqHEfChtt/2buKZw3LFx2kcKB/uZSAvna2/dAw= 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 Reviewed-by: 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 */