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-rw-r--r--net/smc/smc_rx.c511
1 files changed, 511 insertions, 0 deletions
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
new file mode 100644
index 000000000..ffcc9996a
--- /dev/null
+++ b/net/smc/smc_rx.c
@@ -0,0 +1,511 @@
+// 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 <ubraun@linux.vnet.ibm.com>
+ */
+
+#include <linux/net.h>
+#include <linux/rcupdate.h>
+#include <linux/sched/signal.h>
+
+#include <net/sock.h>
+
+#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;
+
+ /* 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,
+ READ_ONCE(sk->sk_err) ||
+ cflags->peer_conn_abort ||
+ READ_ONCE(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;
+}
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