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, 771 insertions, 0 deletions

diff --git a/net/openvswitch/meter.c b/net/openvswitch/meter.c
new file mode 100644
index 000000000..4aaeeae3a
--- /dev/null
+++ b/net/openvswitch/meter.c
@@ -0,0 +1,771 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2017 Nicira, Inc.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/if.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <linux/kernel.h>
+#include <linux/openvswitch.h>
+#include <linux/netlink.h>
+#include <linux/rculist.h>
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include "datapath.h"
+#include "meter.h"
+
+static const struct nla_policy meter_policy[OVS_METER_ATTR_MAX + 1] = {
+	[OVS_METER_ATTR_ID] = { .type = NLA_U32, },
+	[OVS_METER_ATTR_KBPS] = { .type = NLA_FLAG },
+	[OVS_METER_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
+	[OVS_METER_ATTR_BANDS] = { .type = NLA_NESTED },
+	[OVS_METER_ATTR_USED] = { .type = NLA_U64 },
+	[OVS_METER_ATTR_CLEAR] = { .type = NLA_FLAG },
+	[OVS_METER_ATTR_MAX_METERS] = { .type = NLA_U32 },
+	[OVS_METER_ATTR_MAX_BANDS] = { .type = NLA_U32 },
+};
+
+static const struct nla_policy band_policy[OVS_BAND_ATTR_MAX + 1] = {
+	[OVS_BAND_ATTR_TYPE] = { .type = NLA_U32, },
+	[OVS_BAND_ATTR_RATE] = { .type = NLA_U32, },
+	[OVS_BAND_ATTR_BURST] = { .type = NLA_U32, },
+	[OVS_BAND_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
+};
+
+static u32 meter_hash(struct dp_meter_instance *ti, u32 id)
+{
+	return id % ti->n_meters;
+}
+
+static void ovs_meter_free(struct dp_meter *meter)
+{
+	if (!meter)
+		return;
+
+	kfree_rcu(meter, rcu);
+}
+
+/* Call with ovs_mutex or RCU read lock. */
+static struct dp_meter *lookup_meter(const struct dp_meter_table *tbl,
+				     u32 meter_id)
+{
+	struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
+	u32 hash = meter_hash(ti, meter_id);
+	struct dp_meter *meter;
+
+	meter = rcu_dereference_ovsl(ti->dp_meters[hash]);
+	if (meter && likely(meter->id == meter_id))
+		return meter;
+
+	return NULL;
+}
+
+static struct dp_meter_instance *dp_meter_instance_alloc(const u32 size)
+{
+	struct dp_meter_instance *ti;
+
+	ti = kvzalloc_flex(*ti, dp_meters, size);
+	if (!ti)
+		return NULL;
+
+	ti->n_meters = size;
+
+	return ti;
+}
+
+static void dp_meter_instance_free(struct dp_meter_instance *ti)
+{
+	kvfree(ti);
+}
+
+static void dp_meter_instance_free_rcu(struct rcu_head *rcu)
+{
+	struct dp_meter_instance *ti;
+
+	ti = container_of(rcu, struct dp_meter_instance, rcu);
+	kvfree(ti);
+}
+
+static int
+dp_meter_instance_realloc(struct dp_meter_table *tbl, u32 size)
+{
+	struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
+	int n_meters = min(size, ti->n_meters);
+	struct dp_meter_instance *new_ti;
+	int i;
+
+	new_ti = dp_meter_instance_alloc(size);
+	if (!new_ti)
+		return -ENOMEM;
+
+	for (i = 0; i < n_meters; i++)
+		if (rcu_dereference_ovsl(ti->dp_meters[i]))
+			new_ti->dp_meters[i] = ti->dp_meters[i];
+
+	rcu_assign_pointer(tbl->ti, new_ti);
+	call_rcu(&ti->rcu, dp_meter_instance_free_rcu);
+
+	return 0;
+}
+
+static void dp_meter_instance_insert(struct dp_meter_instance *ti,
+				     struct dp_meter *meter)
+{
+	u32 hash;
+
+	hash = meter_hash(ti, meter->id);
+	rcu_assign_pointer(ti->dp_meters[hash], meter);
+}
+
+static void dp_meter_instance_remove(struct dp_meter_instance *ti,
+				     struct dp_meter *meter)
+{
+	u32 hash;
+
+	hash = meter_hash(ti, meter->id);
+	RCU_INIT_POINTER(ti->dp_meters[hash], NULL);
+}
+
+static int attach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
+{
+	struct dp_meter_instance *ti;
+	u32 hash;
+	int err;
+
+	/* That function is thread-safe. */
+	tbl->count++;
+	if (tbl->count >= tbl->max_meters_allowed) {
+		err = -EFBIG;
+		goto attach_err;
+	}
+
+	ti = rcu_dereference_ovsl(tbl->ti);
+	if (tbl->count >= ti->n_meters) {
+		err = dp_meter_instance_realloc(tbl, ti->n_meters * 2);
+		if (err)
+			goto attach_err;
+
+		ti = rcu_dereference_ovsl(tbl->ti);
+	}
+
+	hash = meter_hash(ti, meter->id);
+
+	/* In general, selected slots should be empty, because
+	 * OvS uses id-pool to fetch available ids.
+	 */
+	if (unlikely(rcu_dereference_ovsl(ti->dp_meters[hash]))) {
+		err = -EBUSY;
+		goto attach_err;
+	}
+
+	dp_meter_instance_insert(ti, meter);
+	return 0;
+
+attach_err:
+	tbl->count--;
+	return err;
+}
+
+static int detach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
+{
+	struct dp_meter_instance *ti;
+
+	ASSERT_OVSL();
+	if (!meter)
+		return 0;
+
+	ti = rcu_dereference_ovsl(tbl->ti);
+	dp_meter_instance_remove(ti, meter);
+
+	tbl->count--;
+
+	/* Shrink the meter array if necessary. */
+	if (ti->n_meters > DP_METER_ARRAY_SIZE_MIN &&
+	    tbl->count <= (ti->n_meters / 4)) {
+		int half_size = ti->n_meters / 2;
+		int i;
+
+		/* Avoid hash collision, don't move slots to other place.
+		 * Make sure there are no references of meters in array
+		 * which will be released.
+		 */
+		for (i = half_size; i < ti->n_meters; i++)
+			if (rcu_dereference_ovsl(ti->dp_meters[i]))
+				goto out;
+
+		if (dp_meter_instance_realloc(tbl, half_size))
+			goto shrink_err;
+	}
+
+out:
+	return 0;
+
+shrink_err:
+	dp_meter_instance_insert(ti, meter);
+	tbl->count++;
+	return -ENOMEM;
+}
+
+static struct sk_buff *
+ovs_meter_cmd_reply_start(struct genl_info *info, u8 cmd,
+			  struct ovs_header **ovs_reply_header)
+{
+	struct sk_buff *skb;
+	struct ovs_header *ovs_header = genl_info_userhdr(info);
+
+	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
+	if (!skb)
+		return ERR_PTR(-ENOMEM);
+
+	*ovs_reply_header = genlmsg_put(skb, info->snd_portid,
+					info->snd_seq,
+					&dp_meter_genl_family, 0, cmd);
+	if (!*ovs_reply_header) {
+		nlmsg_free(skb);
+		return ERR_PTR(-EMSGSIZE);
+	}
+	(*ovs_reply_header)->dp_ifindex = ovs_header->dp_ifindex;
+
+	return skb;
+}
+
+static int ovs_meter_cmd_reply_stats(struct sk_buff *reply, u32 meter_id,
+				     struct dp_meter *meter)
+{
+	struct nlattr *nla;
+	struct dp_meter_band *band;
+	u16 i;
+
+	if (nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id))
+		goto error;
+
+	if (nla_put(reply, OVS_METER_ATTR_STATS,
+		    sizeof(struct ovs_flow_stats), &meter->stats))
+		goto error;
+
+	if (nla_put_u64_64bit(reply, OVS_METER_ATTR_USED, meter->used,
+			      OVS_METER_ATTR_PAD))
+		goto error;
+
+	nla = nla_nest_start_noflag(reply, OVS_METER_ATTR_BANDS);
+	if (!nla)
+		goto error;
+
+	band = meter->bands;
+
+	for (i = 0; i < meter->n_bands; ++i, ++band) {
+		struct nlattr *band_nla;
+
+		band_nla = nla_nest_start_noflag(reply, OVS_BAND_ATTR_UNSPEC);
+		if (!band_nla || nla_put(reply, OVS_BAND_ATTR_STATS,
+					 sizeof(struct ovs_flow_stats),
+					 &band->stats))
+			goto error;
+		nla_nest_end(reply, band_nla);
+	}
+	nla_nest_end(reply, nla);
+
+	return 0;
+error:
+	return -EMSGSIZE;
+}
+
+static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info)
+{
+	struct ovs_header *ovs_header = genl_info_userhdr(info);
+	struct ovs_header *ovs_reply_header;
+	struct nlattr *nla, *band_nla;
+	struct sk_buff *reply;
+	struct datapath *dp;
+	int err = -EMSGSIZE;
+
+	reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_FEATURES,
+					  &ovs_reply_header);
+	if (IS_ERR(reply))
+		return PTR_ERR(reply);
+
+	ovs_lock();
+	dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
+	if (!dp) {
+		err = -ENODEV;
+		goto exit_unlock;
+	}
+
+	if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS,
+			dp->meter_tbl.max_meters_allowed))
+		goto exit_unlock;
+
+	ovs_unlock();
+
+	if (nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS))
+		goto nla_put_failure;
+
+	nla = nla_nest_start_noflag(reply, OVS_METER_ATTR_BANDS);
+	if (!nla)
+		goto nla_put_failure;
+
+	band_nla = nla_nest_start_noflag(reply, OVS_BAND_ATTR_UNSPEC);
+	if (!band_nla)
+		goto nla_put_failure;
+	/* Currently only DROP band type is supported. */
+	if (nla_put_u32(reply, OVS_BAND_ATTR_TYPE, OVS_METER_BAND_TYPE_DROP))
+		goto nla_put_failure;
+	nla_nest_end(reply, band_nla);
+	nla_nest_end(reply, nla);
+
+	genlmsg_end(reply, ovs_reply_header);
+	return genlmsg_reply(reply, info);
+
+exit_unlock:
+	ovs_unlock();
+nla_put_failure:
+	nlmsg_free(reply);
+	return err;
+}
+
+static struct dp_meter *dp_meter_create(struct nlattr **a)
+{
+	struct nlattr *nla;
+	int rem;
+	u16 n_bands = 0;
+	struct dp_meter *meter;
+	struct dp_meter_band *band;
+	int err;
+
+	/* Validate attributes, count the bands. */
+	if (!a[OVS_METER_ATTR_BANDS])
+		return ERR_PTR(-EINVAL);
+
+	nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem)
+		if (++n_bands > DP_MAX_BANDS)
+			return ERR_PTR(-EINVAL);
+
+	/* Allocate and set up the meter before locking anything. */
+	meter = kzalloc_flex(*meter, bands, n_bands, GFP_KERNEL_ACCOUNT);
+	if (!meter)
+		return ERR_PTR(-ENOMEM);
+
+	meter->id = nla_get_u32(a[OVS_METER_ATTR_ID]);
+	meter->used = div_u64(ktime_get_ns(), 1000 * 1000);
+	meter->kbps = a[OVS_METER_ATTR_KBPS] ? 1 : 0;
+	meter->keep_stats = !a[OVS_METER_ATTR_CLEAR];
+	spin_lock_init(&meter->lock);
+	if (meter->keep_stats && a[OVS_METER_ATTR_STATS]) {
+		meter->stats = *(struct ovs_flow_stats *)
+			nla_data(a[OVS_METER_ATTR_STATS]);
+	}
+	meter->n_bands = n_bands;
+
+	/* Set up meter bands. */
+	band = meter->bands;
+	nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem) {
+		struct nlattr *attr[OVS_BAND_ATTR_MAX + 1];
+		u32 band_max_delta_t;
+
+		err = nla_parse_deprecated((struct nlattr **)&attr,
+					   OVS_BAND_ATTR_MAX, nla_data(nla),
+					   nla_len(nla), band_policy, NULL);
+		if (err)
+			goto exit_free_meter;
+
+		if (!attr[OVS_BAND_ATTR_TYPE] ||
+		    !attr[OVS_BAND_ATTR_RATE] ||
+		    !attr[OVS_BAND_ATTR_BURST]) {
+			err = -EINVAL;
+			goto exit_free_meter;
+		}
+
+		band->type = nla_get_u32(attr[OVS_BAND_ATTR_TYPE]);
+		band->rate = nla_get_u32(attr[OVS_BAND_ATTR_RATE]);
+		if (band->rate == 0) {
+			err = -EINVAL;
+			goto exit_free_meter;
+		}
+
+		band->burst_size = nla_get_u32(attr[OVS_BAND_ATTR_BURST]);
+		/* Figure out max delta_t that is enough to fill any bucket.
+		 * Keep max_delta_t size to the bucket units:
+		 * pkts => 1/1000 packets, kilobits => bits.
+		 *
+		 * Start with a full bucket.
+		 */
+		band->bucket = band->burst_size * 1000ULL;
+		band_max_delta_t = div_u64(band->bucket, band->rate);
+		if (band_max_delta_t > meter->max_delta_t)
+			meter->max_delta_t = band_max_delta_t;
+		band++;
+	}
+
+	return meter;
+
+exit_free_meter:
+	kfree(meter);
+	return ERR_PTR(err);
+}
+
+static int ovs_meter_cmd_set(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr **a = info->attrs;
+	struct dp_meter *meter, *old_meter;
+	struct sk_buff *reply;
+	struct ovs_header *ovs_reply_header;
+	struct ovs_header *ovs_header = genl_info_userhdr(info);
+	struct dp_meter_table *meter_tbl;
+	struct datapath *dp;
+	int err;
+	u32 meter_id;
+	bool failed;
+
+	if (!a[OVS_METER_ATTR_ID])
+		return -EINVAL;
+
+	meter = dp_meter_create(a);
+	if (IS_ERR(meter))
+		return PTR_ERR(meter);
+
+	reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_SET,
+					  &ovs_reply_header);
+	if (IS_ERR(reply)) {
+		err = PTR_ERR(reply);
+		goto exit_free_meter;
+	}
+
+	ovs_lock();
+	dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
+	if (!dp) {
+		err = -ENODEV;
+		goto exit_unlock;
+	}
+
+	meter_tbl = &dp->meter_tbl;
+	meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
+
+	old_meter = lookup_meter(meter_tbl, meter_id);
+	err = detach_meter(meter_tbl, old_meter);
+	if (err)
+		goto exit_unlock;
+
+	err = attach_meter(meter_tbl, meter);
+	if (err)
+		goto exit_free_old_meter;
+
+	ovs_unlock();
+
+	/* Build response with the meter_id and stats from
+	 * the old meter, if any.
+	 */
+	failed = nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id);
+	WARN_ON(failed);
+	if (old_meter) {
+		spin_lock_bh(&old_meter->lock);
+		if (old_meter->keep_stats) {
+			err = ovs_meter_cmd_reply_stats(reply, meter_id,
+							old_meter);
+			WARN_ON(err);
+		}
+		spin_unlock_bh(&old_meter->lock);
+		ovs_meter_free(old_meter);
+	}
+
+	genlmsg_end(reply, ovs_reply_header);
+	return genlmsg_reply(reply, info);
+
+exit_free_old_meter:
+	ovs_meter_free(old_meter);
+exit_unlock:
+	ovs_unlock();
+	nlmsg_free(reply);
+exit_free_meter:
+	kfree(meter);
+	return err;
+}
+
+static int ovs_meter_cmd_get(struct sk_buff *skb, struct genl_info *info)
+{
+	struct ovs_header *ovs_header = genl_info_userhdr(info);
+	struct ovs_header *ovs_reply_header;
+	struct nlattr **a = info->attrs;
+	struct dp_meter *meter;
+	struct sk_buff *reply;
+	struct datapath *dp;
+	u32 meter_id;
+	int err;
+
+	if (!a[OVS_METER_ATTR_ID])
+		return -EINVAL;
+
+	meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
+
+	reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_GET,
+					  &ovs_reply_header);
+	if (IS_ERR(reply))
+		return PTR_ERR(reply);
+
+	ovs_lock();
+
+	dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
+	if (!dp) {
+		err = -ENODEV;
+		goto exit_unlock;
+	}
+
+	/* Locate meter, copy stats. */
+	meter = lookup_meter(&dp->meter_tbl, meter_id);
+	if (!meter) {
+		err = -ENOENT;
+		goto exit_unlock;
+	}
+
+	spin_lock_bh(&meter->lock);
+	err = ovs_meter_cmd_reply_stats(reply, meter_id, meter);
+	spin_unlock_bh(&meter->lock);
+	if (err)
+		goto exit_unlock;
+
+	ovs_unlock();
+
+	genlmsg_end(reply, ovs_reply_header);
+	return genlmsg_reply(reply, info);
+
+exit_unlock:
+	ovs_unlock();
+	nlmsg_free(reply);
+	return err;
+}
+
+static int ovs_meter_cmd_del(struct sk_buff *skb, struct genl_info *info)
+{
+	struct ovs_header *ovs_header = genl_info_userhdr(info);
+	struct ovs_header *ovs_reply_header;
+	struct nlattr **a = info->attrs;
+	struct dp_meter *old_meter;
+	struct sk_buff *reply;
+	struct datapath *dp;
+	u32 meter_id;
+	int err;
+
+	if (!a[OVS_METER_ATTR_ID])
+		return -EINVAL;
+
+	reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_DEL,
+					  &ovs_reply_header);
+	if (IS_ERR(reply))
+		return PTR_ERR(reply);
+
+	ovs_lock();
+
+	dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
+	if (!dp) {
+		err = -ENODEV;
+		goto exit_unlock;
+	}
+
+	meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
+	old_meter = lookup_meter(&dp->meter_tbl, meter_id);
+	if (old_meter) {
+		spin_lock_bh(&old_meter->lock);
+		err = ovs_meter_cmd_reply_stats(reply, meter_id, old_meter);
+		WARN_ON(err);
+		spin_unlock_bh(&old_meter->lock);
+
+		err = detach_meter(&dp->meter_tbl, old_meter);
+		if (err)
+			goto exit_unlock;
+	}
+
+	ovs_unlock();
+	ovs_meter_free(old_meter);
+	genlmsg_end(reply, ovs_reply_header);
+	return genlmsg_reply(reply, info);
+
+exit_unlock:
+	ovs_unlock();
+	nlmsg_free(reply);
+	return err;
+}
+
+/* Meter action execution.
+ *
+ * Return true 'meter_id' drop band is triggered. The 'skb' should be
+ * dropped by the caller'.
+ */
+bool ovs_meter_execute(struct datapath *dp, struct sk_buff *skb,
+		       struct sw_flow_key *key, u32 meter_id)
+{
+	long long int now_ms = div_u64(ktime_get_ns(), 1000 * 1000);
+	long long int long_delta_ms;
+	struct dp_meter_band *band;
+	struct dp_meter *meter;
+	int i, band_exceeded_max = -1;
+	u32 band_exceeded_rate = 0;
+	u32 delta_ms;
+	u32 cost;
+
+	meter = lookup_meter(&dp->meter_tbl, meter_id);
+	/* Do not drop the packet when there is no meter. */
+	if (!meter)
+		return false;
+
+	/* Lock the meter while using it. */
+	spin_lock(&meter->lock);
+
+	long_delta_ms = (now_ms - meter->used); /* ms */
+	if (long_delta_ms < 0) {
+		/* This condition means that we have several threads fighting
+		 * for a meter lock, and the one who received the packets a
+		 * bit later wins. Assuming that all racing threads received
+		 * packets at the same time to avoid overflow.
+		 */
+		long_delta_ms = 0;
+	}
+
+	/* Make sure delta_ms will not be too large, so that bucket will not
+	 * wrap around below.
+	 */
+	delta_ms = (long_delta_ms > (long long int)meter->max_delta_t)
+		   ? meter->max_delta_t : (u32)long_delta_ms;
+
+	/* Update meter statistics.
+	 */
+	meter->used = now_ms;
+	meter->stats.n_packets += 1;
+	meter->stats.n_bytes += skb->len;
+
+	/* Bucket rate is either in kilobits per second, or in packets per
+	 * second.  We maintain the bucket in the units of either bits or
+	 * 1/1000th of a packet, correspondingly.
+	 * Then, when rate is multiplied with milliseconds, we get the
+	 * bucket units:
+	 * msec * kbps = bits, and
+	 * msec * packets/sec = 1/1000 packets.
+	 *
+	 * 'cost' is the number of bucket units in this packet.
+	 */
+	cost = (meter->kbps) ? skb->len * 8 : 1000;
+
+	/* Update all bands and find the one hit with the highest rate. */
+	for (i = 0; i < meter->n_bands; ++i) {
+		long long int max_bucket_size;
+
+		band = &meter->bands[i];
+		max_bucket_size = band->burst_size * 1000LL;
+
+		band->bucket += delta_ms * band->rate;
+		if (band->bucket > max_bucket_size)
+			band->bucket = max_bucket_size;
+
+		if (band->bucket >= cost) {
+			band->bucket -= cost;
+		} else if (band->rate > band_exceeded_rate) {
+			band_exceeded_rate = band->rate;
+			band_exceeded_max = i;
+		}
+	}
+
+	if (band_exceeded_max >= 0) {
+		/* Update band statistics. */
+		band = &meter->bands[band_exceeded_max];
+		band->stats.n_packets += 1;
+		band->stats.n_bytes += skb->len;
+
+		/* Drop band triggered, let the caller drop the 'skb'.  */
+		if (band->type == OVS_METER_BAND_TYPE_DROP) {
+			spin_unlock(&meter->lock);
+			return true;
+		}
+	}
+
+	spin_unlock(&meter->lock);
+	return false;
+}
+
+static const struct genl_small_ops dp_meter_genl_ops[] = {
+	{ .cmd = OVS_METER_CMD_FEATURES,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.flags = 0,		  /* OK for unprivileged users. */
+		.doit = ovs_meter_cmd_features
+	},
+	{ .cmd = OVS_METER_CMD_SET,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN
+					       *  privilege.
+					       */
+		.doit = ovs_meter_cmd_set,
+	},
+	{ .cmd = OVS_METER_CMD_GET,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.flags = 0,		  /* OK for unprivileged users. */
+		.doit = ovs_meter_cmd_get,
+	},
+	{ .cmd = OVS_METER_CMD_DEL,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN
+					       *  privilege.
+					       */
+		.doit = ovs_meter_cmd_del
+	},
+};
+
+static const struct genl_multicast_group ovs_meter_multicast_group = {
+	.name = OVS_METER_MCGROUP,
+};
+
+struct genl_family dp_meter_genl_family __ro_after_init = {
+	.hdrsize = sizeof(struct ovs_header),
+	.name = OVS_METER_FAMILY,
+	.version = OVS_METER_VERSION,
+	.maxattr = OVS_METER_ATTR_MAX,
+	.policy = meter_policy,
+	.netnsok = true,
+	.parallel_ops = true,
+	.small_ops = dp_meter_genl_ops,
+	.n_small_ops = ARRAY_SIZE(dp_meter_genl_ops),
+	.resv_start_op = OVS_METER_CMD_GET + 1,
+	.mcgrps = &ovs_meter_multicast_group,
+	.n_mcgrps = 1,
+	.module = THIS_MODULE,
+};
+
+int ovs_meters_init(struct datapath *dp)
+{
+	struct dp_meter_table *tbl = &dp->meter_tbl;
+	struct dp_meter_instance *ti;
+	unsigned long free_mem_bytes;
+
+	ti = dp_meter_instance_alloc(DP_METER_ARRAY_SIZE_MIN);
+	if (!ti)
+		return -ENOMEM;
+
+	/* Allow meters in a datapath to use ~3.12% of physical memory. */
+	free_mem_bytes = nr_free_buffer_pages() * (PAGE_SIZE >> 5);
+	tbl->max_meters_allowed = min(free_mem_bytes / sizeof(struct dp_meter),
+				      DP_METER_NUM_MAX);
+	if (!tbl->max_meters_allowed)
+		goto out_err;
+
+	rcu_assign_pointer(tbl->ti, ti);
+	tbl->count = 0;
+
+	return 0;
+
+out_err:
+	dp_meter_instance_free(ti);
+	return -ENOMEM;
+}
+
+void ovs_meters_exit(struct datapath *dp)
+{
+	struct dp_meter_table *tbl = &dp->meter_tbl;
+	struct dp_meter_instance *ti = rcu_dereference_raw(tbl->ti);
+	int i;
+
+	for (i = 0; i < ti->n_meters; i++)
+		ovs_meter_free(rcu_dereference_raw(ti->dp_meters[i]));
+
+	dp_meter_instance_free(ti);
+}