From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ... --- net/smc/smc_rx.c | 515 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 515 insertions(+) create mode 100644 net/smc/smc_rx.c (limited to 'net/smc/smc_rx.c') diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c new file mode 100644 index 000000000..4380d32f5 --- /dev/null +++ b/net/smc/smc_rx.c @@ -0,0 +1,515 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Shared Memory Communications over RDMA (SMC-R) and RoCE + * + * Manage RMBE + * copy new RMBE data into user space + * + * Copyright IBM Corp. 2016 + * + * Author(s): Ursula Braun + */ + +#include +#include +#include +#include + +#include +#include + +#include "smc.h" +#include "smc_core.h" +#include "smc_cdc.h" +#include "smc_tx.h" /* smc_tx_consumer_update() */ +#include "smc_rx.h" +#include "smc_stats.h" +#include "smc_tracepoint.h" + +/* callback implementation to wakeup consumers blocked with smc_rx_wait(). + * indirectly called by smc_cdc_msg_recv_action(). + */ +static void smc_rx_wake_up(struct sock *sk) +{ + struct socket_wq *wq; + + trace_sk_data_ready(sk); + + /* derived from sock_def_readable() */ + /* called already in smc_listen_work() */ + rcu_read_lock(); + wq = rcu_dereference(sk->sk_wq); + if (skwq_has_sleeper(wq)) + wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | EPOLLPRI | + EPOLLRDNORM | EPOLLRDBAND); + sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); + if ((sk->sk_shutdown == SHUTDOWN_MASK) || + (sk->sk_state == SMC_CLOSED)) + sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); + rcu_read_unlock(); +} + +/* Update consumer cursor + * @conn connection to update + * @cons consumer cursor + * @len number of Bytes consumed + * Returns: + * 1 if we should end our receive, 0 otherwise + */ +static int smc_rx_update_consumer(struct smc_sock *smc, + union smc_host_cursor cons, size_t len) +{ + struct smc_connection *conn = &smc->conn; + struct sock *sk = &smc->sk; + bool force = false; + int diff, rc = 0; + + smc_curs_add(conn->rmb_desc->len, &cons, len); + + /* did we process urgent data? */ + if (conn->urg_state == SMC_URG_VALID || conn->urg_rx_skip_pend) { + diff = smc_curs_comp(conn->rmb_desc->len, &cons, + &conn->urg_curs); + if (sock_flag(sk, SOCK_URGINLINE)) { + if (diff == 0) { + force = true; + rc = 1; + conn->urg_state = SMC_URG_READ; + } + } else { + if (diff == 1) { + /* skip urgent byte */ + force = true; + smc_curs_add(conn->rmb_desc->len, &cons, 1); + conn->urg_rx_skip_pend = false; + } else if (diff < -1) + /* we read past urgent byte */ + conn->urg_state = SMC_URG_READ; + } + } + + smc_curs_copy(&conn->local_tx_ctrl.cons, &cons, conn); + + /* send consumer cursor update if required */ + /* similar to advertising new TCP rcv_wnd if required */ + smc_tx_consumer_update(conn, force); + + return rc; +} + +static void smc_rx_update_cons(struct smc_sock *smc, size_t len) +{ + struct smc_connection *conn = &smc->conn; + union smc_host_cursor cons; + + smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); + smc_rx_update_consumer(smc, cons, len); +} + +struct smc_spd_priv { + struct smc_sock *smc; + size_t len; +}; + +static void smc_rx_pipe_buf_release(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + struct smc_spd_priv *priv = (struct smc_spd_priv *)buf->private; + struct smc_sock *smc = priv->smc; + struct smc_connection *conn; + struct sock *sk = &smc->sk; + + if (sk->sk_state == SMC_CLOSED || + sk->sk_state == SMC_PEERFINCLOSEWAIT || + sk->sk_state == SMC_APPFINCLOSEWAIT) + goto out; + conn = &smc->conn; + lock_sock(sk); + smc_rx_update_cons(smc, priv->len); + release_sock(sk); + if (atomic_sub_and_test(priv->len, &conn->splice_pending)) + smc_rx_wake_up(sk); +out: + kfree(priv); + put_page(buf->page); + sock_put(sk); +} + +static const struct pipe_buf_operations smc_pipe_ops = { + .release = smc_rx_pipe_buf_release, + .get = generic_pipe_buf_get +}; + +static void smc_rx_spd_release(struct splice_pipe_desc *spd, + unsigned int i) +{ + put_page(spd->pages[i]); +} + +static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len, + struct smc_sock *smc) +{ + struct smc_link_group *lgr = smc->conn.lgr; + int offset = offset_in_page(src); + struct partial_page *partial; + struct splice_pipe_desc spd; + struct smc_spd_priv **priv; + struct page **pages; + int bytes, nr_pages; + int i; + + nr_pages = !lgr->is_smcd && smc->conn.rmb_desc->is_vm ? + PAGE_ALIGN(len + offset) / PAGE_SIZE : 1; + + pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL); + if (!pages) + goto out; + partial = kcalloc(nr_pages, sizeof(*partial), GFP_KERNEL); + if (!partial) + goto out_page; + priv = kcalloc(nr_pages, sizeof(*priv), GFP_KERNEL); + if (!priv) + goto out_part; + for (i = 0; i < nr_pages; i++) { + priv[i] = kzalloc(sizeof(**priv), GFP_KERNEL); + if (!priv[i]) + goto out_priv; + } + + if (lgr->is_smcd || + (!lgr->is_smcd && !smc->conn.rmb_desc->is_vm)) { + /* smcd or smcr that uses physically contiguous RMBs */ + priv[0]->len = len; + priv[0]->smc = smc; + partial[0].offset = src - (char *)smc->conn.rmb_desc->cpu_addr; + partial[0].len = len; + partial[0].private = (unsigned long)priv[0]; + pages[0] = smc->conn.rmb_desc->pages; + } else { + int size, left = len; + void *buf = src; + /* smcr that uses virtually contiguous RMBs*/ + for (i = 0; i < nr_pages; i++) { + size = min_t(int, PAGE_SIZE - offset, left); + priv[i]->len = size; + priv[i]->smc = smc; + pages[i] = vmalloc_to_page(buf); + partial[i].offset = offset; + partial[i].len = size; + partial[i].private = (unsigned long)priv[i]; + buf += size / sizeof(*buf); + left -= size; + offset = 0; + } + } + spd.nr_pages_max = nr_pages; + spd.nr_pages = nr_pages; + spd.pages = pages; + spd.partial = partial; + spd.ops = &smc_pipe_ops; + spd.spd_release = smc_rx_spd_release; + + bytes = splice_to_pipe(pipe, &spd); + if (bytes > 0) { + sock_hold(&smc->sk); + if (!lgr->is_smcd && smc->conn.rmb_desc->is_vm) { + for (i = 0; i < PAGE_ALIGN(bytes + offset) / PAGE_SIZE; i++) + get_page(pages[i]); + } else { + get_page(smc->conn.rmb_desc->pages); + } + atomic_add(bytes, &smc->conn.splice_pending); + } + kfree(priv); + kfree(partial); + kfree(pages); + + return bytes; + +out_priv: + for (i = (i - 1); i >= 0; i--) + kfree(priv[i]); + kfree(priv); +out_part: + kfree(partial); +out_page: + kfree(pages); +out: + return -ENOMEM; +} + +static int smc_rx_data_available_and_no_splice_pend(struct smc_connection *conn) +{ + return atomic_read(&conn->bytes_to_rcv) && + !atomic_read(&conn->splice_pending); +} + +/* blocks rcvbuf consumer until >=len bytes available or timeout or interrupted + * @smc smc socket + * @timeo pointer to max seconds to wait, pointer to value 0 for no timeout + * @fcrit add'l criterion to evaluate as function pointer + * Returns: + * 1 if at least 1 byte available in rcvbuf or if socket error/shutdown. + * 0 otherwise (nothing in rcvbuf nor timeout, e.g. interrupted). + */ +int smc_rx_wait(struct smc_sock *smc, long *timeo, + int (*fcrit)(struct smc_connection *conn)) +{ + DEFINE_WAIT_FUNC(wait, woken_wake_function); + struct smc_connection *conn = &smc->conn; + struct smc_cdc_conn_state_flags *cflags = + &conn->local_tx_ctrl.conn_state_flags; + struct sock *sk = &smc->sk; + int rc; + + if (fcrit(conn)) + return 1; + sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); + add_wait_queue(sk_sleep(sk), &wait); + rc = sk_wait_event(sk, timeo, + sk->sk_err || + cflags->peer_conn_abort || + sk->sk_shutdown & RCV_SHUTDOWN || + conn->killed || + fcrit(conn), + &wait); + remove_wait_queue(sk_sleep(sk), &wait); + sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); + return rc; +} + +static int smc_rx_recv_urg(struct smc_sock *smc, struct msghdr *msg, int len, + int flags) +{ + struct smc_connection *conn = &smc->conn; + union smc_host_cursor cons; + struct sock *sk = &smc->sk; + int rc = 0; + + if (sock_flag(sk, SOCK_URGINLINE) || + !(conn->urg_state == SMC_URG_VALID) || + conn->urg_state == SMC_URG_READ) + return -EINVAL; + + SMC_STAT_INC(smc, urg_data_cnt); + if (conn->urg_state == SMC_URG_VALID) { + if (!(flags & MSG_PEEK)) + smc->conn.urg_state = SMC_URG_READ; + msg->msg_flags |= MSG_OOB; + if (len > 0) { + if (!(flags & MSG_TRUNC)) + rc = memcpy_to_msg(msg, &conn->urg_rx_byte, 1); + len = 1; + smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); + if (smc_curs_diff(conn->rmb_desc->len, &cons, + &conn->urg_curs) > 1) + conn->urg_rx_skip_pend = true; + /* Urgent Byte was already accounted for, but trigger + * skipping the urgent byte in non-inline case + */ + if (!(flags & MSG_PEEK)) + smc_rx_update_consumer(smc, cons, 0); + } else { + msg->msg_flags |= MSG_TRUNC; + } + + return rc ? -EFAULT : len; + } + + if (sk->sk_state == SMC_CLOSED || sk->sk_shutdown & RCV_SHUTDOWN) + return 0; + + return -EAGAIN; +} + +static bool smc_rx_recvmsg_data_available(struct smc_sock *smc) +{ + struct smc_connection *conn = &smc->conn; + + if (smc_rx_data_available(conn)) + return true; + else if (conn->urg_state == SMC_URG_VALID) + /* we received a single urgent Byte - skip */ + smc_rx_update_cons(smc, 0); + return false; +} + +/* smc_rx_recvmsg - receive data from RMBE + * @msg: copy data to receive buffer + * @pipe: copy data to pipe if set - indicates splice() call + * + * rcvbuf consumer: main API called by socket layer. + * Called under sk lock. + */ +int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, + struct pipe_inode_info *pipe, size_t len, int flags) +{ + size_t copylen, read_done = 0, read_remaining = len; + size_t chunk_len, chunk_off, chunk_len_sum; + struct smc_connection *conn = &smc->conn; + int (*func)(struct smc_connection *conn); + union smc_host_cursor cons; + int readable, chunk; + char *rcvbuf_base; + struct sock *sk; + int splbytes; + long timeo; + int target; /* Read at least these many bytes */ + int rc; + + if (unlikely(flags & MSG_ERRQUEUE)) + return -EINVAL; /* future work for sk.sk_family == AF_SMC */ + + sk = &smc->sk; + if (sk->sk_state == SMC_LISTEN) + return -ENOTCONN; + if (flags & MSG_OOB) + return smc_rx_recv_urg(smc, msg, len, flags); + timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); + target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); + + readable = atomic_read(&conn->bytes_to_rcv); + if (readable >= conn->rmb_desc->len) + SMC_STAT_RMB_RX_FULL(smc, !conn->lnk); + + if (len < readable) + SMC_STAT_RMB_RX_SIZE_SMALL(smc, !conn->lnk); + /* we currently use 1 RMBE per RMB, so RMBE == RMB base addr */ + rcvbuf_base = conn->rx_off + conn->rmb_desc->cpu_addr; + + do { /* while (read_remaining) */ + if (read_done >= target || (pipe && read_done)) + break; + + if (conn->killed) + break; + + if (smc_rx_recvmsg_data_available(smc)) + goto copy; + + if (sk->sk_shutdown & RCV_SHUTDOWN) { + /* smc_cdc_msg_recv_action() could have run after + * above smc_rx_recvmsg_data_available() + */ + if (smc_rx_recvmsg_data_available(smc)) + goto copy; + break; + } + + if (read_done) { + if (sk->sk_err || + sk->sk_state == SMC_CLOSED || + !timeo || + signal_pending(current)) + break; + } else { + if (sk->sk_err) { + read_done = sock_error(sk); + break; + } + if (sk->sk_state == SMC_CLOSED) { + if (!sock_flag(sk, SOCK_DONE)) { + /* This occurs when user tries to read + * from never connected socket. + */ + read_done = -ENOTCONN; + break; + } + break; + } + if (!timeo) + return -EAGAIN; + if (signal_pending(current)) { + read_done = sock_intr_errno(timeo); + break; + } + } + + if (!smc_rx_data_available(conn)) { + smc_rx_wait(smc, &timeo, smc_rx_data_available); + continue; + } + +copy: + /* initialize variables for 1st iteration of subsequent loop */ + /* could be just 1 byte, even after waiting on data above */ + readable = atomic_read(&conn->bytes_to_rcv); + splbytes = atomic_read(&conn->splice_pending); + if (!readable || (msg && splbytes)) { + if (splbytes) + func = smc_rx_data_available_and_no_splice_pend; + else + func = smc_rx_data_available; + smc_rx_wait(smc, &timeo, func); + continue; + } + + smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); + /* subsequent splice() calls pick up where previous left */ + if (splbytes) + smc_curs_add(conn->rmb_desc->len, &cons, splbytes); + if (conn->urg_state == SMC_URG_VALID && + sock_flag(&smc->sk, SOCK_URGINLINE) && + readable > 1) + readable--; /* always stop at urgent Byte */ + /* not more than what user space asked for */ + copylen = min_t(size_t, read_remaining, readable); + /* determine chunks where to read from rcvbuf */ + /* either unwrapped case, or 1st chunk of wrapped case */ + chunk_len = min_t(size_t, copylen, conn->rmb_desc->len - + cons.count); + chunk_len_sum = chunk_len; + chunk_off = cons.count; + smc_rmb_sync_sg_for_cpu(conn); + for (chunk = 0; chunk < 2; chunk++) { + if (!(flags & MSG_TRUNC)) { + if (msg) { + rc = memcpy_to_msg(msg, rcvbuf_base + + chunk_off, + chunk_len); + } else { + rc = smc_rx_splice(pipe, rcvbuf_base + + chunk_off, chunk_len, + smc); + } + if (rc < 0) { + if (!read_done) + read_done = -EFAULT; + goto out; + } + } + read_remaining -= chunk_len; + read_done += chunk_len; + + if (chunk_len_sum == copylen) + break; /* either on 1st or 2nd iteration */ + /* prepare next (== 2nd) iteration */ + chunk_len = copylen - chunk_len; /* remainder */ + chunk_len_sum += chunk_len; + chunk_off = 0; /* modulo offset in recv ring buffer */ + } + + /* update cursors */ + if (!(flags & MSG_PEEK)) { + /* increased in recv tasklet smc_cdc_msg_rcv() */ + smp_mb__before_atomic(); + atomic_sub(copylen, &conn->bytes_to_rcv); + /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */ + smp_mb__after_atomic(); + if (msg && smc_rx_update_consumer(smc, cons, copylen)) + goto out; + } + + trace_smc_rx_recvmsg(smc, copylen); + } while (read_remaining); +out: + return read_done; +} + +/* Initialize receive properties on connection establishment. NB: not __init! */ +void smc_rx_init(struct smc_sock *smc) +{ + smc->sk.sk_data_ready = smc_rx_wake_up; + atomic_set(&smc->conn.splice_pending, 0); + smc->conn.urg_state = SMC_URG_READ; +} -- cgit v1.2.3