Here's the final set of patches towards the removal of sendpage. All the drivers that use sendpage() get switched over to using sendmsg() with MSG_SPLICE_PAGES. skb_splice_from_iter() is given the facility to copy slab data() into fragments - or to coalesce them (in future) with other unspliced buffers in the target skbuff. This means that the caller can work the same way, no matter whether MSG_SPLICE_PAGES is supplied or not and no matter if the protocol just ignores it. If MSG_SPLICE_PAGES is not supplied or if it is just ignored, the data will get copied as normal rather than being spliced. For the moment, skb_splice_from_iter() is equipped with its own fragment allocator - one that has percpu pages to allocate from to deal with parallel callers but that can also drop the percpu lock around calling the page allocator. The following changes are made: (1) Introduce an SMP-safe shared fragment allocator and make skb_splice_from_iter() use it. The allocator is exported so that ocfs2 can use it. This now doesn't alter the existing page_frag_cache allocator. (2) Expose information from the allocator in /proc/. This is useful for debugging it, but could be dropped. (3) Make the protocol drivers behave according to MSG_MORE, not MSG_SENDPAGE_NOTLAST. The latter is restricted to turning on MSG_MORE in the sendpage() wrappers. (4) Make siw, ceph/rds, skb_send_sock, dlm, nvme, smc, ocfs2, drbd and iscsi use sendmsg(), not sendpage and make them specify MSG_MORE instead of MSG_SENDPAGE_NOTLAST. ocfs2 now allocates fragments for a couple of cases where it would otherwise pass in a pointer to shared data that doesn't seem to sufficient locking. (5) Make drbd coalesce its entire message into a single sendmsg(). (6) Kill off sendpage and clean up MSG_SENDPAGE_NOTLAST. I've pushed the patches here also: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=sendpage-3-frag David Changes ======= ver #3) - Remove duplicate decl of skb_splice_from_iter(). - In tcp_bpf, reset msg_flags on each iteration to clear MSG_MORE. - In tcp_bpf, set MSG_MORE if there's more data in the sk_msg. - Split the nvme patch into host and target patches. ver #2) - Wrapped some lines at 80. - Fixed parameter to put_cpu_ptr() to have an '&'. - Use "unsigned int" rather than "unsigned". - Removed duplicate word in comment. - Filled in the commit message on the last patch. Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=51c78a4d532efe9543a4df019ff405f05c6157f6 # part 1 Link: https://lore.kernel.org/r/20230616161301.622169-1-dhowells@xxxxxxxxxx/ # v1 David Howells (18): net: Copy slab data for sendmsg(MSG_SPLICE_PAGES) net: Display info about MSG_SPLICE_PAGES memory handling in proc tcp_bpf, smc, tls, espintcp: Reduce MSG_SENDPAGE_NOTLAST usage siw: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage to transmit ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage net: Use sendmsg(MSG_SPLICE_PAGES) not sendpage in skb_send_sock() ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() rds: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage dlm: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage nvme/host: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage nvme/target: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage smc: Drop smc_sendpage() in favour of smc_sendmsg() + MSG_SPLICE_PAGES ocfs2: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() drbd: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() drdb: Send an entire bio in a single sendmsg iscsi: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) net: Kill MSG_SENDPAGE_NOTLAST Documentation/bpf/map_sockmap.rst | 10 +- Documentation/filesystems/locking.rst | 2 - Documentation/filesystems/vfs.rst | 1 - Documentation/networking/scaling.rst | 4 +- crypto/af_alg.c | 28 -- crypto/algif_aead.c | 22 +- crypto/algif_rng.c | 2 - crypto/algif_skcipher.c | 14 - drivers/block/drbd/drbd_main.c | 88 +++--- drivers/infiniband/sw/siw/siw_qp_tx.c | 231 +++------------- .../chelsio/inline_crypto/chtls/chtls.h | 2 - .../chelsio/inline_crypto/chtls/chtls_io.c | 14 - .../chelsio/inline_crypto/chtls/chtls_main.c | 1 - drivers/nvme/host/tcp.c | 46 ++-- drivers/nvme/target/tcp.c | 46 ++-- drivers/scsi/iscsi_tcp.c | 26 +- drivers/scsi/iscsi_tcp.h | 2 +- drivers/target/iscsi/iscsi_target_util.c | 15 +- fs/dlm/lowcomms.c | 10 +- fs/nfsd/vfs.c | 2 +- fs/ocfs2/cluster/tcp.c | 109 ++++---- include/crypto/if_alg.h | 2 - include/linux/net.h | 8 - include/linux/skbuff.h | 2 + include/linux/socket.h | 4 +- include/net/inet_common.h | 2 - include/net/sock.h | 6 - include/net/tcp.h | 4 - net/appletalk/ddp.c | 1 - net/atm/pvc.c | 1 - net/atm/svc.c | 1 - net/ax25/af_ax25.c | 1 - net/caif/caif_socket.c | 2 - net/can/bcm.c | 1 - net/can/isotp.c | 1 - net/can/j1939/socket.c | 1 - net/can/raw.c | 1 - net/ceph/messenger_v1.c | 58 ++-- net/ceph/messenger_v2.c | 91 ++----- net/core/skbuff.c | 257 ++++++++++++++++-- net/core/sock.c | 35 +-- net/dccp/ipv4.c | 1 - net/dccp/ipv6.c | 1 - net/ieee802154/socket.c | 2 - net/ipv4/af_inet.c | 21 -- net/ipv4/tcp.c | 43 +-- net/ipv4/tcp_bpf.c | 28 +- net/ipv4/tcp_ipv4.c | 1 - net/ipv4/udp.c | 15 - net/ipv4/udp_impl.h | 2 - net/ipv4/udplite.c | 1 - net/ipv6/af_inet6.c | 3 - net/ipv6/raw.c | 1 - net/ipv6/tcp_ipv6.c | 1 - net/kcm/kcmsock.c | 20 -- net/key/af_key.c | 1 - net/l2tp/l2tp_ip.c | 1 - net/l2tp/l2tp_ip6.c | 1 - net/llc/af_llc.c | 1 - net/mctp/af_mctp.c | 1 - net/mptcp/protocol.c | 2 - net/netlink/af_netlink.c | 1 - net/netrom/af_netrom.c | 1 - net/packet/af_packet.c | 2 - net/phonet/socket.c | 2 - net/qrtr/af_qrtr.c | 1 - net/rds/af_rds.c | 1 - net/rds/tcp_send.c | 74 ++--- net/rose/af_rose.c | 1 - net/rxrpc/af_rxrpc.c | 1 - net/sctp/protocol.c | 1 - net/smc/af_smc.c | 29 -- net/smc/smc_stats.c | 2 +- net/smc/smc_stats.h | 1 - net/smc/smc_tx.c | 20 +- net/smc/smc_tx.h | 2 - net/socket.c | 48 ---- net/tipc/socket.c | 3 - net/tls/tls.h | 6 - net/tls/tls_device.c | 24 +- net/tls/tls_main.c | 9 +- net/tls/tls_sw.c | 37 +-- net/unix/af_unix.c | 19 -- net/vmw_vsock/af_vsock.c | 3 - net/x25/af_x25.c | 1 - net/xdp/xsk.c | 1 - net/xfrm/espintcp.c | 10 +- .../perf/trace/beauty/include/linux/socket.h | 1 - tools/perf/trace/beauty/msg_flags.c | 3 - 89 files changed, 544 insertions(+), 1061 deletions(-)