Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 877 insertions, 0 deletions

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
new file mode 100644
index 000000000..ed2c9a510
--- /dev/null
+++ b/net/rxrpc/sendmsg.c
@@ -0,0 +1,877 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AF_RXRPC sendmsg() implementation.
+ *
+ * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/net.h>
+#include <linux/gfp.h>
+#include <linux/skbuff.h>
+#include <linux/export.h>
+#include <linux/sched/signal.h>
+
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+/*
+ * Propose an abort to be made in the I/O thread.
+ */
+bool rxrpc_propose_abort(struct rxrpc_call *call, s32 abort_code, int error,
+			 enum rxrpc_abort_reason why)
+{
+	_enter("{%d},%d,%d,%u", call->debug_id, abort_code, error, why);
+
+	if (!call->send_abort && !rxrpc_call_is_complete(call)) {
+		call->send_abort_why = why;
+		call->send_abort_err = error;
+		call->send_abort_seq = 0;
+		trace_rxrpc_abort_call(call, abort_code);
+		/* Request abort locklessly vs rxrpc_input_call_event(). */
+		smp_store_release(&call->send_abort, abort_code);
+		rxrpc_poke_call(call, rxrpc_call_poke_abort);
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * Wait for a call to become connected.  Interruption here doesn't cause the
+ * call to be aborted.
+ */
+static int rxrpc_wait_to_be_connected(struct rxrpc_call *call, long *timeo)
+{
+	DECLARE_WAITQUEUE(myself, current);
+	int ret = 0;
+
+	_enter("%d", call->debug_id);
+
+	if (rxrpc_call_state(call) != RXRPC_CALL_CLIENT_AWAIT_CONN)
+		goto no_wait;
+
+	add_wait_queue_exclusive(&call->waitq, &myself);
+
+	for (;;) {
+		switch (call->interruptibility) {
+		case RXRPC_INTERRUPTIBLE:
+		case RXRPC_PREINTERRUPTIBLE:
+			set_current_state(TASK_INTERRUPTIBLE);
+			break;
+		case RXRPC_UNINTERRUPTIBLE:
+		default:
+			set_current_state(TASK_UNINTERRUPTIBLE);
+			break;
+		}
+
+		if (rxrpc_call_state(call) != RXRPC_CALL_CLIENT_AWAIT_CONN)
+			break;
+		if ((call->interruptibility == RXRPC_INTERRUPTIBLE ||
+		     call->interruptibility == RXRPC_PREINTERRUPTIBLE) &&
+		    signal_pending(current)) {
+			ret = sock_intr_errno(*timeo);
+			break;
+		}
+		*timeo = schedule_timeout(*timeo);
+	}
+
+	remove_wait_queue(&call->waitq, &myself);
+	__set_current_state(TASK_RUNNING);
+
+no_wait:
+	if (ret == 0 && rxrpc_call_is_complete(call))
+		ret = call->error;
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Return true if there's sufficient Tx queue space.
+ */
+static bool rxrpc_check_tx_space(struct rxrpc_call *call, rxrpc_seq_t *_tx_win)
+{
+	rxrpc_seq_t tx_bottom = READ_ONCE(call->tx_bottom);
+
+	if (_tx_win)
+		*_tx_win = tx_bottom;
+	return call->send_top - tx_bottom < 256;
+}
+
+/*
+ * Wait for space to appear in the Tx queue or a signal to occur.
+ */
+static int rxrpc_wait_for_tx_window_intr(struct rxrpc_sock *rx,
+					 struct rxrpc_call *call,
+					 long *timeo)
+{
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (rxrpc_check_tx_space(call, NULL))
+			return 0;
+
+		if (rxrpc_call_is_complete(call))
+			return call->error;
+
+		if (signal_pending(current))
+			return sock_intr_errno(*timeo);
+
+		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
+		*timeo = schedule_timeout(*timeo);
+	}
+}
+
+/*
+ * Wait for space to appear in the Tx queue uninterruptibly, but with
+ * a timeout of 2*RTT if no progress was made and a signal occurred.
+ */
+static int rxrpc_wait_for_tx_window_waitall(struct rxrpc_sock *rx,
+					    struct rxrpc_call *call)
+{
+	rxrpc_seq_t tx_start, tx_win;
+	signed long rtt, timeout;
+
+	rtt = READ_ONCE(call->srtt_us) >> 3;
+	rtt = usecs_to_jiffies(rtt) * 2;
+	if (rtt < 2)
+		rtt = 2;
+
+	timeout = rtt;
+	tx_start = READ_ONCE(call->tx_bottom);
+
+	for (;;) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+
+		if (rxrpc_check_tx_space(call, &tx_win))
+			return 0;
+
+		if (rxrpc_call_is_complete(call))
+			return call->error;
+
+		if (timeout == 0 &&
+		    tx_win == tx_start && signal_pending(current))
+			return -EINTR;
+
+		if (tx_win != tx_start) {
+			timeout = rtt;
+			tx_start = tx_win;
+		}
+
+		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
+		timeout = schedule_timeout(timeout);
+	}
+}
+
+/*
+ * Wait for space to appear in the Tx queue uninterruptibly.
+ */
+static int rxrpc_wait_for_tx_window_nonintr(struct rxrpc_sock *rx,
+					    struct rxrpc_call *call,
+					    long *timeo)
+{
+	for (;;) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		if (rxrpc_check_tx_space(call, NULL))
+			return 0;
+
+		if (rxrpc_call_is_complete(call))
+			return call->error;
+
+		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
+		*timeo = schedule_timeout(*timeo);
+	}
+}
+
+/*
+ * wait for space to appear in the transmit/ACK window
+ * - caller holds the socket locked
+ */
+static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
+				    struct rxrpc_call *call,
+				    long *timeo,
+				    bool waitall)
+{
+	DECLARE_WAITQUEUE(myself, current);
+	int ret;
+
+	_enter(",{%u,%u,%u}",
+	       call->tx_bottom, call->tx_top, call->tx_winsize);
+
+	add_wait_queue(&call->waitq, &myself);
+
+	switch (call->interruptibility) {
+	case RXRPC_INTERRUPTIBLE:
+		if (waitall)
+			ret = rxrpc_wait_for_tx_window_waitall(rx, call);
+		else
+			ret = rxrpc_wait_for_tx_window_intr(rx, call, timeo);
+		break;
+	case RXRPC_PREINTERRUPTIBLE:
+	case RXRPC_UNINTERRUPTIBLE:
+	default:
+		ret = rxrpc_wait_for_tx_window_nonintr(rx, call, timeo);
+		break;
+	}
+
+	remove_wait_queue(&call->waitq, &myself);
+	set_current_state(TASK_RUNNING);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Notify the owner of the call that the transmit phase is ended and the last
+ * packet has been queued.
+ */
+static void rxrpc_notify_end_tx(struct rxrpc_sock *rx, struct rxrpc_call *call,
+				rxrpc_notify_end_tx_t notify_end_tx)
+{
+	if (notify_end_tx)
+		notify_end_tx(&rx->sk, call, call->user_call_ID);
+}
+
+/*
+ * Queue a DATA packet for transmission, set the resend timeout and send
+ * the packet immediately.  Returns the error from rxrpc_send_data_packet()
+ * in case the caller wants to do something with it.
+ */
+static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
+			       struct rxrpc_txbuf *txb,
+			       rxrpc_notify_end_tx_t notify_end_tx)
+{
+	struct rxrpc_txqueue *sq = call->send_queue;
+	rxrpc_seq_t seq = txb->seq;
+	bool poke, last = txb->flags & RXRPC_LAST_PACKET;
+	int ix = seq & RXRPC_TXQ_MASK;
+	rxrpc_inc_stat(call->rxnet, stat_tx_data);
+
+	ASSERTCMP(txb->seq, ==, call->send_top + 1);
+
+	if (last)
+		trace_rxrpc_txqueue(call, rxrpc_txqueue_queue_last);
+	else
+		trace_rxrpc_txqueue(call, rxrpc_txqueue_queue);
+
+	if (WARN_ON_ONCE(sq->bufs[ix]))
+		trace_rxrpc_tq(call, sq, seq, rxrpc_tq_queue_dup);
+	else
+		trace_rxrpc_tq(call, sq, seq, rxrpc_tq_queue);
+
+	/* Add the packet to the call's output buffer */
+	poke = (READ_ONCE(call->tx_bottom) == call->send_top);
+	sq->bufs[ix] = txb;
+	/* Order send_top after the queue->next pointer and txb content. */
+	smp_store_release(&call->send_top, seq);
+	if (last) {
+		set_bit(RXRPC_CALL_TX_NO_MORE, &call->flags);
+		rxrpc_notify_end_tx(rx, call, notify_end_tx);
+		call->send_queue = NULL;
+	}
+
+	if (poke)
+		rxrpc_poke_call(call, rxrpc_call_poke_start);
+}
+
+/*
+ * Allocate a new txqueue unit and add it to the transmission queue.
+ */
+static int rxrpc_alloc_txqueue(struct sock *sk, struct rxrpc_call *call)
+{
+	struct rxrpc_txqueue *tq;
+
+	tq = kzalloc_obj(*tq, sk->sk_allocation);
+	if (!tq)
+		return -ENOMEM;
+
+	tq->xmit_ts_base = KTIME_MIN;
+	for (int i = 0; i < RXRPC_NR_TXQUEUE; i++)
+		tq->segment_xmit_ts[i] = UINT_MAX;
+
+	if (call->send_queue) {
+		tq->qbase = call->send_top + 1;
+		call->send_queue->next = tq;
+		call->send_queue = tq;
+	} else if (WARN_ON(call->tx_queue)) {
+		kfree(tq);
+		return -ENOMEM;
+	} else {
+		/* We start at seq 1, so pretend seq 0 is hard-acked. */
+		tq->nr_reported_acks = 1;
+		tq->segment_acked = 1UL;
+		tq->qbase = 0;
+		call->tx_qbase = 0;
+		call->send_queue = tq;
+		call->tx_qtail = tq;
+		call->tx_queue = tq;
+	}
+
+	trace_rxrpc_tq(call, tq, call->send_top, rxrpc_tq_alloc);
+	return 0;
+}
+
+/*
+ * send data through a socket
+ * - must be called in process context
+ * - The caller holds the call user access mutex, but not the socket lock.
+ */
+static int rxrpc_send_data(struct rxrpc_sock *rx,
+			   struct rxrpc_call *call,
+			   struct msghdr *msg, size_t len,
+			   rxrpc_notify_end_tx_t notify_end_tx,
+			   bool *_dropped_lock)
+{
+	struct rxrpc_txbuf *txb;
+	struct sock *sk = &rx->sk;
+	enum rxrpc_call_state state;
+	long timeo;
+	bool more = msg->msg_flags & MSG_MORE;
+	int ret, copied = 0;
+
+	if (test_bit(RXRPC_CALL_TX_NO_MORE, &call->flags)) {
+		trace_rxrpc_abort(call->debug_id, rxrpc_sendmsg_late_send,
+				  call->cid, call->call_id, call->rx_consumed,
+				  0, -EPROTO);
+		return -EPROTO;
+	}
+
+	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+
+	ret = rxrpc_wait_to_be_connected(call, &timeo);
+	if (ret < 0)
+		return ret;
+
+	if (call->conn->state == RXRPC_CONN_CLIENT_UNSECURED) {
+		ret = rxrpc_init_client_conn_security(call->conn);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* this should be in poll */
+	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+reload:
+	txb = call->tx_pending;
+	call->tx_pending = NULL;
+	if (txb)
+		rxrpc_see_txbuf(txb, rxrpc_txbuf_see_send_more);
+
+	ret = -EPIPE;
+	if (sk->sk_shutdown & SEND_SHUTDOWN)
+		goto maybe_error;
+	state = rxrpc_call_state(call);
+	ret = -ESHUTDOWN;
+	if (state >= RXRPC_CALL_COMPLETE)
+		goto maybe_error;
+	ret = -EPROTO;
+	if (state != RXRPC_CALL_CLIENT_PRE_SEND &&
+	    state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
+	    state != RXRPC_CALL_SERVER_ACK_REQUEST &&
+	    state != RXRPC_CALL_SERVER_SEND_REPLY) {
+		/* Request phase complete for this client call */
+		trace_rxrpc_abort(call->debug_id, rxrpc_sendmsg_late_send,
+				  call->cid, call->call_id, call->rx_consumed,
+				  0, -EPROTO);
+		goto maybe_error;
+	}
+
+	ret = -EMSGSIZE;
+	if (call->tx_total_len != -1) {
+		if (len - copied > call->tx_total_len)
+			goto maybe_error;
+		if (!more && len - copied != call->tx_total_len)
+			goto maybe_error;
+	}
+
+	do {
+		if (!txb) {
+			size_t remain;
+
+			_debug("alloc");
+
+			if (!rxrpc_check_tx_space(call, NULL))
+				goto wait_for_space;
+
+			/* See if we need to begin/extend the Tx queue. */
+			if (!call->send_queue || !((call->send_top + 1) & RXRPC_TXQ_MASK)) {
+				ret = rxrpc_alloc_txqueue(sk, call);
+				if (ret < 0)
+					goto maybe_error;
+			}
+
+			/* Work out the maximum size of a packet.  Assume that
+			 * the security header is going to be in the padded
+			 * region (enc blocksize), but the trailer is not.
+			 */
+			remain = more ? INT_MAX : msg_data_left(msg);
+			txb = call->conn->security->alloc_txbuf(call, remain, sk->sk_allocation);
+			if (!txb) {
+				ret = -ENOMEM;
+				goto maybe_error;
+			}
+		}
+
+		_debug("append");
+
+		/* append next segment of data to the current buffer */
+		if (msg_data_left(msg) > 0) {
+			size_t copy = umin(txb->space, msg_data_left(msg));
+
+			_debug("add %zu", copy);
+			if (!copy_from_iter_full(txb->data + txb->offset,
+						 copy, &msg->msg_iter))
+				goto efault;
+			_debug("added");
+			txb->space -= copy;
+			txb->len += copy;
+			txb->offset += copy;
+			copied += copy;
+			if (call->tx_total_len != -1)
+				call->tx_total_len -= copy;
+		}
+
+		/* check for the far side aborting the call or a network error
+		 * occurring */
+		if (rxrpc_call_is_complete(call))
+			goto call_terminated;
+
+		/* add the packet to the send queue if it's now full */
+		if (!txb->space ||
+		    (msg_data_left(msg) == 0 && !more)) {
+			if (msg_data_left(msg) == 0 && !more)
+				txb->flags |= RXRPC_LAST_PACKET;
+
+			ret = call->security->secure_packet(call, txb);
+			if (ret < 0)
+				goto out;
+			rxrpc_queue_packet(rx, call, txb, notify_end_tx);
+			txb = NULL;
+		}
+	} while (msg_data_left(msg) > 0);
+
+success:
+	ret = copied;
+	if (rxrpc_call_is_complete(call) &&
+	    call->error < 0)
+		ret = call->error;
+out:
+	call->tx_pending = txb;
+	_leave(" = %d", ret);
+	return ret;
+
+call_terminated:
+	rxrpc_put_txbuf(txb, rxrpc_txbuf_put_send_aborted);
+	_leave(" = %d", call->error);
+	return call->error;
+
+maybe_error:
+	if (copied)
+		goto success;
+	goto out;
+
+efault:
+	ret = -EFAULT;
+	goto out;
+
+wait_for_space:
+	ret = -EAGAIN;
+	if (msg->msg_flags & MSG_DONTWAIT)
+		goto maybe_error;
+	mutex_unlock(&call->user_mutex);
+	*_dropped_lock = true;
+	ret = rxrpc_wait_for_tx_window(rx, call, &timeo,
+				       msg->msg_flags & MSG_WAITALL);
+	if (ret < 0)
+		goto maybe_error;
+	if (call->interruptibility == RXRPC_INTERRUPTIBLE) {
+		if (mutex_lock_interruptible(&call->user_mutex) < 0) {
+			ret = sock_intr_errno(timeo);
+			goto maybe_error;
+		}
+	} else {
+		mutex_lock(&call->user_mutex);
+	}
+	*_dropped_lock = false;
+	goto reload;
+}
+
+/*
+ * extract control messages from the sendmsg() control buffer
+ */
+static int rxrpc_sendmsg_cmsg(struct msghdr *msg, struct rxrpc_send_params *p)
+{
+	struct cmsghdr *cmsg;
+	bool got_user_ID = false;
+	int len;
+
+	if (msg->msg_controllen == 0)
+		return -EINVAL;
+
+	for_each_cmsghdr(cmsg, msg) {
+		if (!CMSG_OK(msg, cmsg))
+			return -EINVAL;
+
+		len = cmsg->cmsg_len - sizeof(struct cmsghdr);
+		_debug("CMSG %d, %d, %d",
+		       cmsg->cmsg_level, cmsg->cmsg_type, len);
+
+		if (cmsg->cmsg_level != SOL_RXRPC)
+			continue;
+
+		switch (cmsg->cmsg_type) {
+		case RXRPC_USER_CALL_ID:
+			if (msg->msg_flags & MSG_CMSG_COMPAT) {
+				if (len != sizeof(u32))
+					return -EINVAL;
+				p->call.user_call_ID = *(u32 *)CMSG_DATA(cmsg);
+			} else {
+				if (len != sizeof(unsigned long))
+					return -EINVAL;
+				p->call.user_call_ID = *(unsigned long *)
+					CMSG_DATA(cmsg);
+			}
+			got_user_ID = true;
+			break;
+
+		case RXRPC_ABORT:
+			if (p->command != RXRPC_CMD_SEND_DATA)
+				return -EINVAL;
+			p->command = RXRPC_CMD_SEND_ABORT;
+			if (len != sizeof(p->abort_code))
+				return -EINVAL;
+			p->abort_code = *(unsigned int *)CMSG_DATA(cmsg);
+			if (p->abort_code == 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_CHARGE_ACCEPT:
+			if (p->command != RXRPC_CMD_SEND_DATA)
+				return -EINVAL;
+			p->command = RXRPC_CMD_CHARGE_ACCEPT;
+			if (len != 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_EXCLUSIVE_CALL:
+			p->exclusive = true;
+			if (len != 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_UPGRADE_SERVICE:
+			p->upgrade = true;
+			if (len != 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_TX_LENGTH:
+			if (p->call.tx_total_len != -1 || len != sizeof(__s64))
+				return -EINVAL;
+			p->call.tx_total_len = *(__s64 *)CMSG_DATA(cmsg);
+			if (p->call.tx_total_len < 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_SET_CALL_TIMEOUT:
+			if (len & 3 || len < 4 || len > 12)
+				return -EINVAL;
+			memcpy(&p->call.timeouts, CMSG_DATA(cmsg), len);
+			p->call.nr_timeouts = len / 4;
+			if (p->call.timeouts.hard > INT_MAX / HZ)
+				return -ERANGE;
+			if (p->call.nr_timeouts >= 2 && p->call.timeouts.idle > 60 * 60 * 1000)
+				return -ERANGE;
+			if (p->call.nr_timeouts >= 3 && p->call.timeouts.normal > 60 * 60 * 1000)
+				return -ERANGE;
+			break;
+
+		default:
+			return -EINVAL;
+		}
+	}
+
+	if (!got_user_ID)
+		return -EINVAL;
+	if (p->call.tx_total_len != -1 && p->command != RXRPC_CMD_SEND_DATA)
+		return -EINVAL;
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * Create a new client call for sendmsg().
+ * - Called with the socket lock held, which it must release.
+ * - If it returns a call, the call's lock will need releasing by the caller.
+ */
+static struct rxrpc_call *
+rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
+				  struct rxrpc_send_params *p)
+	__releases(&rx->sk.sk_lock)
+	__acquires(&call->user_mutex)
+{
+	struct rxrpc_conn_parameters cp;
+	struct rxrpc_peer *peer;
+	struct rxrpc_call *call;
+	struct key *key;
+
+	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
+
+	_enter("");
+
+	if (!msg->msg_name) {
+		release_sock(&rx->sk);
+		return ERR_PTR(-EDESTADDRREQ);
+	}
+
+	peer = rxrpc_lookup_peer(rx->local, srx, GFP_KERNEL);
+	if (!peer) {
+		release_sock(&rx->sk);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	key = rx->key;
+	if (key && !rx->key->payload.data[0])
+		key = NULL;
+
+	memset(&cp, 0, sizeof(cp));
+	cp.local		= rx->local;
+	cp.peer			= peer;
+	cp.key			= key;
+	cp.security_level	= rx->min_sec_level;
+	cp.exclusive		= rx->exclusive | p->exclusive;
+	cp.upgrade		= p->upgrade;
+	cp.service_id		= srx->srx_service;
+	call = rxrpc_new_client_call(rx, &cp, &p->call, GFP_KERNEL,
+				     atomic_inc_return(&rxrpc_debug_id));
+	/* The socket is now unlocked */
+
+	rxrpc_put_peer(peer, rxrpc_peer_put_application);
+	_leave(" = %p\n", call);
+	return call;
+}
+
+/*
+ * send a message forming part of a client call through an RxRPC socket
+ * - caller holds the socket locked
+ * - the socket may be either a client socket or a server socket
+ */
+int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
+{
+	struct rxrpc_call *call;
+	bool dropped_lock = false;
+	int ret;
+
+	struct rxrpc_send_params p = {
+		.call.tx_total_len	= -1,
+		.call.user_call_ID	= 0,
+		.call.nr_timeouts	= 0,
+		.call.interruptibility	= RXRPC_INTERRUPTIBLE,
+		.abort_code		= 0,
+		.command		= RXRPC_CMD_SEND_DATA,
+		.exclusive		= false,
+		.upgrade		= false,
+	};
+
+	_enter("");
+
+	ret = rxrpc_sendmsg_cmsg(msg, &p);
+	if (ret < 0)
+		goto error_release_sock;
+
+	if (p.command == RXRPC_CMD_CHARGE_ACCEPT) {
+		ret = -EINVAL;
+		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
+			goto error_release_sock;
+		ret = rxrpc_user_charge_accept(rx, p.call.user_call_ID);
+		goto error_release_sock;
+	}
+
+	call = rxrpc_find_call_by_user_ID(rx, p.call.user_call_ID);
+	if (!call) {
+		ret = -EBADSLT;
+		if (p.command != RXRPC_CMD_SEND_DATA)
+			goto error_release_sock;
+		call = rxrpc_new_client_call_for_sendmsg(rx, msg, &p);
+		/* The socket is now unlocked... */
+		if (IS_ERR(call))
+			return PTR_ERR(call);
+		/* ... and we have the call lock. */
+		p.call.nr_timeouts = 0;
+		ret = 0;
+		if (rxrpc_call_is_complete(call))
+			goto out_put_unlock;
+	} else {
+		switch (rxrpc_call_state(call)) {
+		case RXRPC_CALL_CLIENT_AWAIT_CONN:
+		case RXRPC_CALL_SERVER_RECV_REQUEST:
+			if (p.command == RXRPC_CMD_SEND_ABORT)
+				break;
+			fallthrough;
+		case RXRPC_CALL_UNINITIALISED:
+		case RXRPC_CALL_SERVER_PREALLOC:
+			rxrpc_put_call(call, rxrpc_call_put_sendmsg);
+			ret = -EBUSY;
+			goto error_release_sock;
+		default:
+			break;
+		}
+
+		ret = mutex_lock_interruptible(&call->user_mutex);
+		release_sock(&rx->sk);
+		if (ret < 0) {
+			ret = -ERESTARTSYS;
+			goto error_put;
+		}
+
+		if (p.call.tx_total_len != -1) {
+			ret = -EINVAL;
+			if (call->tx_total_len != -1 ||
+			    call->tx_pending ||
+			    call->tx_top != 0)
+				goto out_put_unlock;
+			call->tx_total_len = p.call.tx_total_len;
+		}
+	}
+
+	switch (p.call.nr_timeouts) {
+	case 3:
+		WRITE_ONCE(call->next_rx_timo, p.call.timeouts.normal);
+		fallthrough;
+	case 2:
+		WRITE_ONCE(call->next_req_timo, p.call.timeouts.idle);
+		fallthrough;
+	case 1:
+		if (p.call.timeouts.hard > 0) {
+			ktime_t delay = ms_to_ktime(p.call.timeouts.hard * MSEC_PER_SEC);
+
+			WRITE_ONCE(call->expect_term_by,
+				   ktime_add(p.call.timeouts.hard,
+					     ktime_get_real()));
+			trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_hard);
+			rxrpc_poke_call(call, rxrpc_call_poke_set_timeout);
+
+		}
+		break;
+	}
+
+	if (rxrpc_call_is_complete(call)) {
+		/* it's too late for this call */
+		ret = -ESHUTDOWN;
+		goto out_put_unlock;
+	}
+
+	switch (p.command) {
+	case RXRPC_CMD_SEND_ABORT:
+		rxrpc_propose_abort(call, p.abort_code, -ECONNABORTED,
+				    rxrpc_abort_call_sendmsg);
+		ret = 0;
+		break;
+	case RXRPC_CMD_SEND_DATA:
+		ret = rxrpc_send_data(rx, call, msg, len, NULL, &dropped_lock);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+out_put_unlock:
+	if (!dropped_lock)
+		mutex_unlock(&call->user_mutex);
+error_put:
+	rxrpc_put_call(call, rxrpc_call_put_sendmsg);
+	_leave(" = %d", ret);
+	return ret;
+
+error_release_sock:
+	release_sock(&rx->sk);
+	return ret;
+}
+
+/**
+ * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
+ * @sock: The socket the call is on
+ * @call: The call to send data through
+ * @msg: The data to send
+ * @len: The amount of data to send
+ * @notify_end_tx: Notification that the last packet is queued.
+ *
+ * Allow a kernel service to send data on a call.  The call must be in an state
+ * appropriate to sending data.  No control data should be supplied in @msg,
+ * nor should an address be supplied.  MSG_MORE should be flagged if there's
+ * more data to come, otherwise this data will end the transmission phase.
+ *
+ * Return: %0 if successful and a negative error code otherwise.
+ */
+int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
+			   struct msghdr *msg, size_t len,
+			   rxrpc_notify_end_tx_t notify_end_tx)
+{
+	bool dropped_lock = false;
+	int ret;
+
+	_enter("{%d},", call->debug_id);
+
+	ASSERTCMP(msg->msg_name, ==, NULL);
+	ASSERTCMP(msg->msg_control, ==, NULL);
+
+	mutex_lock(&call->user_mutex);
+
+	ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len,
+			      notify_end_tx, &dropped_lock);
+	if (ret == -ESHUTDOWN)
+		ret = call->error;
+
+	if (!dropped_lock)
+		mutex_unlock(&call->user_mutex);
+	_leave(" = %d", ret);
+	return ret;
+}
+EXPORT_SYMBOL(rxrpc_kernel_send_data);
+
+/**
+ * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
+ * @sock: The socket the call is on
+ * @call: The call to be aborted
+ * @abort_code: The abort code to stick into the ABORT packet
+ * @error: Local error value
+ * @why: Indication as to why.
+ *
+ * Allow a kernel service to abort a call if it's still in an abortable state.
+ *
+ * Return: %true if the call was aborted, %false if it was already complete.
+ */
+bool rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
+			     u32 abort_code, int error, enum rxrpc_abort_reason why)
+{
+	bool aborted;
+
+	_enter("{%d},%d,%d,%u", call->debug_id, abort_code, error, why);
+
+	mutex_lock(&call->user_mutex);
+	aborted = rxrpc_propose_abort(call, abort_code, error, why);
+	mutex_unlock(&call->user_mutex);
+	return aborted;
+}
+EXPORT_SYMBOL(rxrpc_kernel_abort_call);
+
+/**
+ * rxrpc_kernel_set_tx_length - Set the total Tx length on a call
+ * @sock: The socket the call is on
+ * @call: The call to be informed
+ * @tx_total_len: The amount of data to be transmitted for this call
+ *
+ * Allow a kernel service to set the total transmit length on a call.  This
+ * allows buffer-to-packet encrypt-and-copy to be performed.
+ *
+ * This function is primarily for use for setting the reply length since the
+ * request length can be set when beginning the call.
+ */
+void rxrpc_kernel_set_tx_length(struct socket *sock, struct rxrpc_call *call,
+				s64 tx_total_len)
+{
+	WARN_ON(call->tx_total_len != -1);
+	call->tx_total_len = tx_total_len;
+}
+EXPORT_SYMBOL(rxrpc_kernel_set_tx_length);