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, 1219 insertions, 0 deletions

diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
new file mode 100644
index 000000000..1e0f9d193
--- /dev/null
+++ b/net/openvswitch/flow_table.c
@@ -0,0 +1,1219 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2007-2014 Nicira, Inc.
+ */
+
+#include "flow.h"
+#include "datapath.h"
+#include "flow_netlink.h"
+#include <linux/uaccess.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.h>
+#include <linux/if_vlan.h>
+#include <net/llc_pdu.h>
+#include <linux/kernel.h>
+#include <linux/jhash.h>
+#include <linux/jiffies.h>
+#include <linux/llc.h>
+#include <linux/module.h>
+#include <linux/in.h>
+#include <linux/rcupdate.h>
+#include <linux/cpumask.h>
+#include <linux/if_arp.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/sctp.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/icmp.h>
+#include <linux/icmpv6.h>
+#include <linux/rculist.h>
+#include <linux/sort.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <net/ndisc.h>
+
+#define TBL_MIN_BUCKETS		1024
+#define MASK_ARRAY_SIZE_MIN	16
+#define REHASH_INTERVAL		(10 * 60 * HZ)
+
+#define MC_DEFAULT_HASH_ENTRIES	256
+#define MC_HASH_SHIFT		8
+#define MC_HASH_SEGS		((sizeof(uint32_t) * 8) / MC_HASH_SHIFT)
+
+static struct kmem_cache *flow_cache;
+struct kmem_cache *flow_stats_cache __read_mostly;
+
+static u16 range_n_bytes(const struct sw_flow_key_range *range)
+{
+	return range->end - range->start;
+}
+
+void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src,
+		       bool full, const struct sw_flow_mask *mask)
+{
+	int start = full ? 0 : mask->range.start;
+	int len = full ? sizeof *dst : range_n_bytes(&mask->range);
+	const long *m = (const long *)((const u8 *)&mask->key + start);
+	const long *s = (const long *)((const u8 *)src + start);
+	long *d = (long *)((u8 *)dst + start);
+	int i;
+
+	/* If 'full' is true then all of 'dst' is fully initialized. Otherwise,
+	 * if 'full' is false the memory outside of the 'mask->range' is left
+	 * uninitialized. This can be used as an optimization when further
+	 * operations on 'dst' only use contents within 'mask->range'.
+	 */
+	for (i = 0; i < len; i += sizeof(long))
+		*d++ = *s++ & *m++;
+}
+
+struct sw_flow *ovs_flow_alloc(void)
+{
+	struct sw_flow *flow;
+	struct sw_flow_stats *stats;
+
+	flow = kmem_cache_zalloc(flow_cache, GFP_KERNEL);
+	if (!flow)
+		return ERR_PTR(-ENOMEM);
+
+	flow->stats_last_writer = -1;
+	flow->cpu_used_mask = (struct cpumask *)&flow->stats[nr_cpu_ids];
+
+	/* Initialize the default stat node. */
+	stats = kmem_cache_alloc_node(flow_stats_cache,
+				      GFP_KERNEL | __GFP_ZERO,
+				      node_online(0) ? 0 : NUMA_NO_NODE);
+	if (!stats)
+		goto err;
+
+	spin_lock_init(&stats->lock);
+
+	RCU_INIT_POINTER(flow->stats[0], stats);
+
+	cpumask_set_cpu(0, flow->cpu_used_mask);
+
+	return flow;
+err:
+	kmem_cache_free(flow_cache, flow);
+	return ERR_PTR(-ENOMEM);
+}
+
+int ovs_flow_tbl_count(const struct flow_table *table)
+{
+	return table->count;
+}
+
+static void flow_free(struct sw_flow *flow)
+{
+	unsigned int cpu;
+
+	if (ovs_identifier_is_key(&flow->id))
+		kfree(flow->id.unmasked_key);
+	if (flow->sf_acts)
+		ovs_nla_free_flow_actions((struct sw_flow_actions __force *)
+					  flow->sf_acts);
+
+	for_each_cpu(cpu, flow->cpu_used_mask) {
+		if (flow->stats[cpu])
+			kmem_cache_free(flow_stats_cache,
+					(struct sw_flow_stats __force *)flow->stats[cpu]);
+	}
+
+	kmem_cache_free(flow_cache, flow);
+}
+
+static void rcu_free_flow_callback(struct rcu_head *rcu)
+{
+	struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
+
+	flow_free(flow);
+}
+
+void ovs_flow_free(struct sw_flow *flow, bool deferred)
+{
+	if (!flow)
+		return;
+
+	if (deferred)
+		call_rcu(&flow->rcu, rcu_free_flow_callback);
+	else
+		flow_free(flow);
+}
+
+static void __table_instance_destroy(struct table_instance *ti)
+{
+	kvfree(ti->buckets);
+	kfree(ti);
+}
+
+static struct table_instance *table_instance_alloc(int new_size)
+{
+	struct table_instance *ti = kmalloc_obj(*ti);
+	int i;
+
+	if (!ti)
+		return NULL;
+
+	ti->buckets = kvmalloc_objs(struct hlist_head, new_size);
+	if (!ti->buckets) {
+		kfree(ti);
+		return NULL;
+	}
+
+	for (i = 0; i < new_size; i++)
+		INIT_HLIST_HEAD(&ti->buckets[i]);
+
+	ti->n_buckets = new_size;
+	ti->node_ver = 0;
+	ti->hash_seed = get_random_u32();
+
+	return ti;
+}
+
+static void __mask_array_destroy(struct mask_array *ma)
+{
+	free_percpu(ma->masks_usage_stats);
+	kfree(ma);
+}
+
+static void mask_array_rcu_cb(struct rcu_head *rcu)
+{
+	struct mask_array *ma = container_of(rcu, struct mask_array, rcu);
+
+	__mask_array_destroy(ma);
+}
+
+static void tbl_mask_array_reset_counters(struct mask_array *ma)
+{
+	int i, cpu;
+
+	/* As the per CPU counters are not atomic we can not go ahead and
+	 * reset them from another CPU. To be able to still have an approximate
+	 * zero based counter we store the value at reset, and subtract it
+	 * later when processing.
+	 */
+	for (i = 0; i < ma->max; i++) {
+		ma->masks_usage_zero_cntr[i] = 0;
+
+		for_each_possible_cpu(cpu) {
+			struct mask_array_stats *stats;
+			unsigned int start;
+			u64 counter;
+
+			stats = per_cpu_ptr(ma->masks_usage_stats, cpu);
+			do {
+				start = u64_stats_fetch_begin(&stats->syncp);
+				counter = stats->usage_cntrs[i];
+			} while (u64_stats_fetch_retry(&stats->syncp, start));
+
+			ma->masks_usage_zero_cntr[i] += counter;
+		}
+	}
+}
+
+static struct mask_array *tbl_mask_array_alloc(int size)
+{
+	struct mask_array *new;
+
+	size = max(MASK_ARRAY_SIZE_MIN, size);
+	new = kzalloc(struct_size(new, masks, size) +
+		      sizeof(u64) * size, GFP_KERNEL);
+	if (!new)
+		return NULL;
+
+	new->masks_usage_zero_cntr = (u64 *)((u8 *)new +
+					     struct_size(new, masks, size));
+
+	new->masks_usage_stats = __alloc_percpu(sizeof(struct mask_array_stats) +
+						sizeof(u64) * size,
+						__alignof__(u64));
+	if (!new->masks_usage_stats) {
+		kfree(new);
+		return NULL;
+	}
+
+	new->count = 0;
+	new->max = size;
+
+	return new;
+}
+
+static int tbl_mask_array_realloc(struct flow_table *tbl, int size)
+{
+	struct mask_array *old;
+	struct mask_array *new;
+
+	new = tbl_mask_array_alloc(size);
+	if (!new)
+		return -ENOMEM;
+
+	old = ovsl_dereference(tbl->mask_array);
+	if (old) {
+		int i;
+
+		for (i = 0; i < old->max; i++) {
+			if (ovsl_dereference(old->masks[i]))
+				new->masks[new->count++] = old->masks[i];
+		}
+	}
+
+	rcu_assign_pointer(tbl->mask_array, new);
+
+	if (old)
+		call_rcu(&old->rcu, mask_array_rcu_cb);
+
+	return 0;
+}
+
+static int tbl_mask_array_add_mask(struct flow_table *tbl,
+				   struct sw_flow_mask *new)
+{
+	struct mask_array *ma = ovsl_dereference(tbl->mask_array);
+	int err, ma_count = READ_ONCE(ma->count);
+
+	if (ma_count >= ma->max) {
+		err = tbl_mask_array_realloc(tbl, ma->max +
+						  MASK_ARRAY_SIZE_MIN);
+		if (err)
+			return err;
+
+		ma = ovsl_dereference(tbl->mask_array);
+	} else {
+		/* On every add or delete we need to reset the counters so
+		 * every new mask gets a fair chance of being prioritized.
+		 */
+		tbl_mask_array_reset_counters(ma);
+	}
+
+	BUG_ON(ovsl_dereference(ma->masks[ma_count]));
+
+	rcu_assign_pointer(ma->masks[ma_count], new);
+	WRITE_ONCE(ma->count, ma_count + 1);
+
+	return 0;
+}
+
+static void tbl_mask_array_del_mask(struct flow_table *tbl,
+				    struct sw_flow_mask *mask)
+{
+	struct mask_array *ma = ovsl_dereference(tbl->mask_array);
+	int i, ma_count = READ_ONCE(ma->count);
+
+	/* Remove the deleted mask pointers from the array */
+	for (i = 0; i < ma_count; i++) {
+		if (mask == ovsl_dereference(ma->masks[i]))
+			goto found;
+	}
+
+	BUG();
+	return;
+
+found:
+	WRITE_ONCE(ma->count, ma_count - 1);
+
+	rcu_assign_pointer(ma->masks[i], ma->masks[ma_count - 1]);
+	RCU_INIT_POINTER(ma->masks[ma_count - 1], NULL);
+
+	kfree_rcu(mask, rcu);
+
+	/* Shrink the mask array if necessary. */
+	if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) &&
+	    ma_count <= (ma->max / 3))
+		tbl_mask_array_realloc(tbl, ma->max / 2);
+	else
+		tbl_mask_array_reset_counters(ma);
+
+}
+
+/* Remove 'mask' from the mask list, if it is not needed any more. */
+static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
+{
+	if (mask) {
+		/* ovs-lock is required to protect mask-refcount and
+		 * mask list.
+		 */
+		ASSERT_OVSL();
+		BUG_ON(!mask->ref_count);
+		mask->ref_count--;
+
+		if (!mask->ref_count)
+			tbl_mask_array_del_mask(tbl, mask);
+	}
+}
+
+static void __mask_cache_destroy(struct mask_cache *mc)
+{
+	free_percpu(mc->mask_cache);
+	kfree(mc);
+}
+
+static void mask_cache_rcu_cb(struct rcu_head *rcu)
+{
+	struct mask_cache *mc = container_of(rcu, struct mask_cache, rcu);
+
+	__mask_cache_destroy(mc);
+}
+
+static struct mask_cache *tbl_mask_cache_alloc(u32 size)
+{
+	struct mask_cache_entry __percpu *cache = NULL;
+	struct mask_cache *new;
+
+	/* Only allow size to be 0, or a power of 2, and does not exceed
+	 * percpu allocation size.
+	 */
+	if ((!is_power_of_2(size) && size != 0) ||
+	    (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE)
+		return NULL;
+
+	new = kzalloc_obj(*new);
+	if (!new)
+		return NULL;
+
+	new->cache_size = size;
+	if (new->cache_size > 0) {
+		cache = __alloc_percpu(array_size(sizeof(struct mask_cache_entry),
+						  new->cache_size),
+				       __alignof__(struct mask_cache_entry));
+		if (!cache) {
+			kfree(new);
+			return NULL;
+		}
+	}
+
+	new->mask_cache = cache;
+	return new;
+}
+int ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size)
+{
+	struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache);
+	struct mask_cache *new;
+
+	if (size == mc->cache_size)
+		return 0;
+
+	if ((!is_power_of_2(size) && size != 0) ||
+	    (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE)
+		return -EINVAL;
+
+	new = tbl_mask_cache_alloc(size);
+	if (!new)
+		return -ENOMEM;
+
+	rcu_assign_pointer(table->mask_cache, new);
+	call_rcu(&mc->rcu, mask_cache_rcu_cb);
+
+	return 0;
+}
+
+int ovs_flow_tbl_init(struct flow_table *table)
+{
+	struct table_instance *ti, *ufid_ti;
+	struct mask_cache *mc;
+	struct mask_array *ma;
+
+	mc = tbl_mask_cache_alloc(MC_DEFAULT_HASH_ENTRIES);
+	if (!mc)
+		return -ENOMEM;
+
+	ma = tbl_mask_array_alloc(MASK_ARRAY_SIZE_MIN);
+	if (!ma)
+		goto free_mask_cache;
+
+	ti = table_instance_alloc(TBL_MIN_BUCKETS);
+	if (!ti)
+		goto free_mask_array;
+
+	ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS);
+	if (!ufid_ti)
+		goto free_ti;
+
+	rcu_assign_pointer(table->ti, ti);
+	rcu_assign_pointer(table->ufid_ti, ufid_ti);
+	rcu_assign_pointer(table->mask_array, ma);
+	rcu_assign_pointer(table->mask_cache, mc);
+	table->last_rehash = jiffies;
+	table->count = 0;
+	table->ufid_count = 0;
+	return 0;
+
+free_ti:
+	__table_instance_destroy(ti);
+free_mask_array:
+	__mask_array_destroy(ma);
+free_mask_cache:
+	__mask_cache_destroy(mc);
+	return -ENOMEM;
+}
+
+static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
+{
+	struct table_instance *ti;
+
+	ti = container_of(rcu, struct table_instance, rcu);
+	__table_instance_destroy(ti);
+}
+
+static void table_instance_flow_free(struct flow_table *table,
+				     struct table_instance *ti,
+				     struct table_instance *ufid_ti,
+				     struct sw_flow *flow)
+{
+	hlist_del_rcu(&flow->flow_table.node[ti->node_ver]);
+	table->count--;
+
+	if (ovs_identifier_is_ufid(&flow->id)) {
+		hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]);
+		table->ufid_count--;
+	}
+
+	flow_mask_remove(table, flow->mask);
+}
+
+/* Must be called with OVS mutex held. */
+void table_instance_flow_flush(struct flow_table *table,
+			       struct table_instance *ti,
+			       struct table_instance *ufid_ti)
+{
+	int i;
+
+	for (i = 0; i < ti->n_buckets; i++) {
+		struct hlist_head *head = &ti->buckets[i];
+		struct hlist_node *n;
+		struct sw_flow *flow;
+
+		hlist_for_each_entry_safe(flow, n, head,
+					  flow_table.node[ti->node_ver]) {
+
+			table_instance_flow_free(table, ti, ufid_ti,
+						 flow);
+			ovs_flow_free(flow, true);
+		}
+	}
+
+	if (WARN_ON(table->count != 0 ||
+		    table->ufid_count != 0)) {
+		table->count = 0;
+		table->ufid_count = 0;
+	}
+}
+
+static void table_instance_destroy(struct table_instance *ti,
+				   struct table_instance *ufid_ti)
+{
+	call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
+	call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb);
+}
+
+/* No need for locking this function is called from RCU callback or
+ * error path.
+ */
+void ovs_flow_tbl_destroy(struct flow_table *table)
+{
+	struct table_instance *ti = rcu_dereference_raw(table->ti);
+	struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti);
+	struct mask_cache *mc = rcu_dereference_raw(table->mask_cache);
+	struct mask_array *ma = rcu_dereference_raw(table->mask_array);
+
+	call_rcu(&mc->rcu, mask_cache_rcu_cb);
+	call_rcu(&ma->rcu, mask_array_rcu_cb);
+	table_instance_destroy(ti, ufid_ti);
+}
+
+struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti,
+				       u32 *bucket, u32 *last)
+{
+	struct sw_flow *flow;
+	struct hlist_head *head;
+	int ver;
+	int i;
+
+	ver = ti->node_ver;
+	while (*bucket < ti->n_buckets) {
+		i = 0;
+		head = &ti->buckets[*bucket];
+		hlist_for_each_entry_rcu(flow, head, flow_table.node[ver]) {
+			if (i < *last) {
+				i++;
+				continue;
+			}
+			*last = i + 1;
+			return flow;
+		}
+		(*bucket)++;
+		*last = 0;
+	}
+
+	return NULL;
+}
+
+static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash)
+{
+	hash = jhash_1word(hash, ti->hash_seed);
+	return &ti->buckets[hash & (ti->n_buckets - 1)];
+}
+
+static void table_instance_insert(struct table_instance *ti,
+				  struct sw_flow *flow)
+{
+	struct hlist_head *head;
+
+	head = find_bucket(ti, flow->flow_table.hash);
+	hlist_add_head_rcu(&flow->flow_table.node[ti->node_ver], head);
+}
+
+static void ufid_table_instance_insert(struct table_instance *ti,
+				       struct sw_flow *flow)
+{
+	struct hlist_head *head;
+
+	head = find_bucket(ti, flow->ufid_table.hash);
+	hlist_add_head_rcu(&flow->ufid_table.node[ti->node_ver], head);
+}
+
+static void flow_table_copy_flows(struct table_instance *old,
+				  struct table_instance *new, bool ufid)
+{
+	int old_ver;
+	int i;
+
+	old_ver = old->node_ver;
+	new->node_ver = !old_ver;
+
+	/* Insert in new table. */
+	for (i = 0; i < old->n_buckets; i++) {
+		struct sw_flow *flow;
+		struct hlist_head *head = &old->buckets[i];
+
+		if (ufid)
+			hlist_for_each_entry_rcu(flow, head,
+						 ufid_table.node[old_ver],
+						 lockdep_ovsl_is_held())
+				ufid_table_instance_insert(new, flow);
+		else
+			hlist_for_each_entry_rcu(flow, head,
+						 flow_table.node[old_ver],
+						 lockdep_ovsl_is_held())
+				table_instance_insert(new, flow);
+	}
+}
+
+static struct table_instance *table_instance_rehash(struct table_instance *ti,
+						    int n_buckets, bool ufid)
+{
+	struct table_instance *new_ti;
+
+	new_ti = table_instance_alloc(n_buckets);
+	if (!new_ti)
+		return NULL;
+
+	flow_table_copy_flows(ti, new_ti, ufid);
+
+	return new_ti;
+}
+
+int ovs_flow_tbl_flush(struct flow_table *flow_table)
+{
+	struct table_instance *old_ti, *new_ti;
+	struct table_instance *old_ufid_ti, *new_ufid_ti;
+
+	new_ti = table_instance_alloc(TBL_MIN_BUCKETS);
+	if (!new_ti)
+		return -ENOMEM;
+	new_ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS);
+	if (!new_ufid_ti)
+		goto err_free_ti;
+
+	old_ti = ovsl_dereference(flow_table->ti);
+	old_ufid_ti = ovsl_dereference(flow_table->ufid_ti);
+
+	rcu_assign_pointer(flow_table->ti, new_ti);
+	rcu_assign_pointer(flow_table->ufid_ti, new_ufid_ti);
+	flow_table->last_rehash = jiffies;
+
+	table_instance_flow_flush(flow_table, old_ti, old_ufid_ti);
+	table_instance_destroy(old_ti, old_ufid_ti);
+	return 0;
+
+err_free_ti:
+	__table_instance_destroy(new_ti);
+	return -ENOMEM;
+}
+
+static u32 flow_hash(const struct sw_flow_key *key,
+		     const struct sw_flow_key_range *range)
+{
+	const u32 *hash_key = (const u32 *)((const u8 *)key + range->start);
+
+	/* Make sure number of hash bytes are multiple of u32. */
+	int hash_u32s = range_n_bytes(range) >> 2;
+
+	return jhash2(hash_key, hash_u32s, 0);
+}
+
+static int flow_key_start(const struct sw_flow_key *key)
+{
+	if (key->tun_proto)
+		return 0;
+	else
+		return rounddown(offsetof(struct sw_flow_key, phy),
+				 sizeof(long));
+}
+
+static bool cmp_key(const struct sw_flow_key *key1,
+		    const struct sw_flow_key *key2,
+		    int key_start, int key_end)
+{
+	const long *cp1 = (const long *)((const u8 *)key1 + key_start);
+	const long *cp2 = (const long *)((const u8 *)key2 + key_start);
+	int i;
+
+	for (i = key_start; i < key_end; i += sizeof(long))
+		if (*cp1++ ^ *cp2++)
+			return false;
+
+	return true;
+}
+
+static bool flow_cmp_masked_key(const struct sw_flow *flow,
+				const struct sw_flow_key *key,
+				const struct sw_flow_key_range *range)
+{
+	return cmp_key(&flow->key, key, range->start, range->end);
+}
+
+static bool ovs_flow_cmp_unmasked_key(const struct sw_flow *flow,
+				      const struct sw_flow_match *match)
+{
+	struct sw_flow_key *key = match->key;
+	int key_start = flow_key_start(key);
+	int key_end = match->range.end;
+
+	BUG_ON(ovs_identifier_is_ufid(&flow->id));
+	return cmp_key(flow->id.unmasked_key, key, key_start, key_end);
+}
+
+static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
+					  const struct sw_flow_key *unmasked,
+					  const struct sw_flow_mask *mask,
+					  u32 *n_mask_hit)
+{
+	struct sw_flow *flow;
+	struct hlist_head *head;
+	u32 hash;
+	struct sw_flow_key masked_key;
+
+	ovs_flow_mask_key(&masked_key, unmasked, false, mask);
+	hash = flow_hash(&masked_key, &mask->range);
+	head = find_bucket(ti, hash);
+	(*n_mask_hit)++;
+
+	hlist_for_each_entry_rcu(flow, head, flow_table.node[ti->node_ver],
+				 lockdep_ovsl_is_held()) {
+		if (flow->mask == mask && flow->flow_table.hash == hash &&
+		    flow_cmp_masked_key(flow, &masked_key, &mask->range))
+			return flow;
+	}
+	return NULL;
+}
+
+/* Flow lookup does full lookup on flow table. It starts with
+ * mask from index passed in *index.
+ * This function MUST be called with BH disabled due to the use
+ * of CPU specific variables.
+ */
+static struct sw_flow *flow_lookup(struct flow_table *tbl,
+				   struct table_instance *ti,
+				   struct mask_array *ma,
+				   const struct sw_flow_key *key,
+				   u32 *n_mask_hit,
+				   u32 *n_cache_hit,
+				   u32 *index)
+{
+	struct mask_array_stats *stats = this_cpu_ptr(ma->masks_usage_stats);
+	struct sw_flow *flow;
+	struct sw_flow_mask *mask;
+	int i;
+
+	if (likely(*index < ma->max)) {
+		mask = rcu_dereference_ovsl(ma->masks[*index]);
+		if (mask) {
+			flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
+			if (flow) {
+				u64_stats_update_begin(&stats->syncp);
+				stats->usage_cntrs[*index]++;
+				u64_stats_update_end(&stats->syncp);
+				(*n_cache_hit)++;
+				return flow;
+			}
+		}
+	}
+
+	for (i = 0; i < ma->max; i++)  {
+
+		if (i == *index)
+			continue;
+
+		mask = rcu_dereference_ovsl(ma->masks[i]);
+		if (unlikely(!mask))
+			break;
+
+		flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
+		if (flow) { /* Found */
+			*index = i;
+			u64_stats_update_begin(&stats->syncp);
+			stats->usage_cntrs[*index]++;
+			u64_stats_update_end(&stats->syncp);
+			return flow;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * mask_cache maps flow to probable mask. This cache is not tightly
+ * coupled cache, It means updates to  mask list can result in inconsistent
+ * cache entry in mask cache.
+ * This is per cpu cache and is divided in MC_HASH_SEGS segments.
+ * In case of a hash collision the entry is hashed in next segment.
+ * */
+struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
+					  const struct sw_flow_key *key,
+					  u32 skb_hash,
+					  u32 *n_mask_hit,
+					  u32 *n_cache_hit)
+{
+	struct mask_cache *mc = rcu_dereference(tbl->mask_cache);
+	struct mask_array *ma = rcu_dereference(tbl->mask_array);
+	struct table_instance *ti = rcu_dereference(tbl->ti);
+	struct mask_cache_entry *entries, *ce;
+	struct sw_flow *flow;
+	u32 hash;
+	int seg;
+
+	*n_mask_hit = 0;
+	*n_cache_hit = 0;
+	if (unlikely(!skb_hash || mc->cache_size == 0)) {
+		u32 mask_index = 0;
+		u32 cache = 0;
+
+		return flow_lookup(tbl, ti, ma, key, n_mask_hit, &cache,
+				   &mask_index);
+	}
+
+	/* Pre and post recirulation flows usually have the same skb_hash
+	 * value. To avoid hash collisions, rehash the 'skb_hash' with
+	 * 'recirc_id'.  */
+	if (key->recirc_id)
+		skb_hash = jhash_1word(skb_hash, key->recirc_id);
+
+	ce = NULL;
+	hash = skb_hash;
+	entries = this_cpu_ptr(mc->mask_cache);
+
+	/* Find the cache entry 'ce' to operate on. */
+	for (seg = 0; seg < MC_HASH_SEGS; seg++) {
+		int index = hash & (mc->cache_size - 1);
+		struct mask_cache_entry *e;
+
+		e = &entries[index];
+		if (e->skb_hash == skb_hash) {
+			flow = flow_lookup(tbl, ti, ma, key, n_mask_hit,
+					   n_cache_hit, &e->mask_index);
+			if (!flow)
+				e->skb_hash = 0;
+			return flow;
+		}
+
+		if (!ce || e->skb_hash < ce->skb_hash)
+			ce = e;  /* A better replacement cache candidate. */
+
+		hash >>= MC_HASH_SHIFT;
+	}
+
+	/* Cache miss, do full lookup. */
+	flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, n_cache_hit,
+			   &ce->mask_index);
+	if (flow)
+		ce->skb_hash = skb_hash;
+
+	*n_cache_hit = 0;
+	return flow;
+}
+
+struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
+				    const struct sw_flow_key *key)
+{
+	struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
+	struct mask_array *ma = rcu_dereference_ovsl(tbl->mask_array);
+	u32 __always_unused n_mask_hit;
+	u32 __always_unused n_cache_hit;
+	struct sw_flow *flow;
+	u32 index = 0;
+
+	/* This function gets called trough the netlink interface and therefore
+	 * is preemptible. However, flow_lookup() function needs to be called
+	 * with BH disabled due to CPU specific variables.
+	 */
+	local_bh_disable();
+	flow = flow_lookup(tbl, ti, ma, key, &n_mask_hit, &n_cache_hit, &index);
+	local_bh_enable();
+	return flow;
+}
+
+struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
+					  const struct sw_flow_match *match)
+{
+	struct mask_array *ma = ovsl_dereference(tbl->mask_array);
+	int i;
+
+	/* Always called under ovs-mutex. */
+	for (i = 0; i < ma->max; i++) {
+		struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
+		u32 __always_unused n_mask_hit;
+		struct sw_flow_mask *mask;
+		struct sw_flow *flow;
+
+		mask = ovsl_dereference(ma->masks[i]);
+		if (!mask)
+			continue;
+
+		flow = masked_flow_lookup(ti, match->key, mask, &n_mask_hit);
+		if (flow && ovs_identifier_is_key(&flow->id) &&
+		    ovs_flow_cmp_unmasked_key(flow, match)) {
+			return flow;
+		}
+	}
+
+	return NULL;
+}
+
+static u32 ufid_hash(const struct sw_flow_id *sfid)
+{
+	return jhash(sfid->ufid, sfid->ufid_len, 0);
+}
+
+static bool ovs_flow_cmp_ufid(const struct sw_flow *flow,
+			      const struct sw_flow_id *sfid)
+{
+	if (flow->id.ufid_len != sfid->ufid_len)
+		return false;
+
+	return !memcmp(flow->id.ufid, sfid->ufid, sfid->ufid_len);
+}
+
+bool ovs_flow_cmp(const struct sw_flow *flow,
+		  const struct sw_flow_match *match)
+{
+	if (ovs_identifier_is_ufid(&flow->id))
+		return flow_cmp_masked_key(flow, match->key, &match->range);
+
+	return ovs_flow_cmp_unmasked_key(flow, match);
+}
+
+struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl,
+					 const struct sw_flow_id *ufid)
+{
+	struct table_instance *ti = rcu_dereference_ovsl(tbl->ufid_ti);
+	struct sw_flow *flow;
+	struct hlist_head *head;
+	u32 hash;
+
+	hash = ufid_hash(ufid);
+	head = find_bucket(ti, hash);
+	hlist_for_each_entry_rcu(flow, head, ufid_table.node[ti->node_ver],
+				 lockdep_ovsl_is_held()) {
+		if (flow->ufid_table.hash == hash &&
+		    ovs_flow_cmp_ufid(flow, ufid))
+			return flow;
+	}
+	return NULL;
+}
+
+int ovs_flow_tbl_num_masks(const struct flow_table *table)
+{
+	struct mask_array *ma = rcu_dereference_ovsl(table->mask_array);
+	return READ_ONCE(ma->count);
+}
+
+u32 ovs_flow_tbl_masks_cache_size(const struct flow_table *table)
+{
+	struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache);
+
+	return READ_ONCE(mc->cache_size);
+}
+
+static struct table_instance *table_instance_expand(struct table_instance *ti,
+						    bool ufid)
+{
+	return table_instance_rehash(ti, ti->n_buckets * 2, ufid);
+}
+
+/* Must be called with OVS mutex held. */
+void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow)
+{
+	struct table_instance *ti = ovsl_dereference(table->ti);
+	struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti);
+
+	BUG_ON(table->count == 0);
+	table_instance_flow_free(table, ti, ufid_ti, flow);
+}
+
+static struct sw_flow_mask *mask_alloc(void)
+{
+	struct sw_flow_mask *mask;
+
+	mask = kmalloc_obj(*mask);
+	if (mask)
+		mask->ref_count = 1;
+
+	return mask;
+}
+
+static bool mask_equal(const struct sw_flow_mask *a,
+		       const struct sw_flow_mask *b)
+{
+	const u8 *a_ = (const u8 *)&a->key + a->range.start;
+	const u8 *b_ = (const u8 *)&b->key + b->range.start;
+
+	return  (a->range.end == b->range.end)
+		&& (a->range.start == b->range.start)
+		&& (memcmp(a_, b_, range_n_bytes(&a->range)) == 0);
+}
+
+static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl,
+					   const struct sw_flow_mask *mask)
+{
+	struct mask_array *ma;
+	int i;
+
+	ma = ovsl_dereference(tbl->mask_array);
+	for (i = 0; i < ma->max; i++) {
+		struct sw_flow_mask *t;
+		t = ovsl_dereference(ma->masks[i]);
+
+		if (t && mask_equal(mask, t))
+			return t;
+	}
+
+	return NULL;
+}
+
+/* Add 'mask' into the mask list, if it is not already there. */
+static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
+			    const struct sw_flow_mask *new)
+{
+	struct sw_flow_mask *mask;
+
+	mask = flow_mask_find(tbl, new);
+	if (!mask) {
+		/* Allocate a new mask if none exists. */
+		mask = mask_alloc();
+		if (!mask)
+			return -ENOMEM;
+		mask->key = new->key;
+		mask->range = new->range;
+
+		/* Add mask to mask-list. */
+		if (tbl_mask_array_add_mask(tbl, mask)) {
+			kfree(mask);
+			return -ENOMEM;
+		}
+	} else {
+		BUG_ON(!mask->ref_count);
+		mask->ref_count++;
+	}
+
+	flow->mask = mask;
+	return 0;
+}
+
+/* Must be called with OVS mutex held. */
+static void flow_key_insert(struct flow_table *table, struct sw_flow *flow)
+{
+	struct table_instance *new_ti = NULL;
+	struct table_instance *ti;
+
+	flow->flow_table.hash = flow_hash(&flow->key, &flow->mask->range);
+	ti = ovsl_dereference(table->ti);
+	table_instance_insert(ti, flow);
+	table->count++;
+
+	/* Expand table, if necessary, to make room. */
+	if (table->count > ti->n_buckets)
+		new_ti = table_instance_expand(ti, false);
+	else if (time_after(jiffies, table->last_rehash + REHASH_INTERVAL))
+		new_ti = table_instance_rehash(ti, ti->n_buckets, false);
+
+	if (new_ti) {
+		rcu_assign_pointer(table->ti, new_ti);
+		call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
+		table->last_rehash = jiffies;
+	}
+}
+
+/* Must be called with OVS mutex held. */
+static void flow_ufid_insert(struct flow_table *table, struct sw_flow *flow)
+{
+	struct table_instance *ti;
+
+	flow->ufid_table.hash = ufid_hash(&flow->id);
+	ti = ovsl_dereference(table->ufid_ti);
+	ufid_table_instance_insert(ti, flow);
+	table->ufid_count++;
+
+	/* Expand table, if necessary, to make room. */
+	if (table->ufid_count > ti->n_buckets) {
+		struct table_instance *new_ti;
+
+		new_ti = table_instance_expand(ti, true);
+		if (new_ti) {
+			rcu_assign_pointer(table->ufid_ti, new_ti);
+			call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
+		}
+	}
+}
+
+/* Must be called with OVS mutex held. */
+int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow,
+			const struct sw_flow_mask *mask)
+{
+	int err;
+
+	err = flow_mask_insert(table, flow, mask);
+	if (err)
+		return err;
+	flow_key_insert(table, flow);
+	if (ovs_identifier_is_ufid(&flow->id))
+		flow_ufid_insert(table, flow);
+
+	return 0;
+}
+
+static int compare_mask_and_count(const void *a, const void *b)
+{
+	const struct mask_count *mc_a = a;
+	const struct mask_count *mc_b = b;
+
+	return (s64)mc_b->counter - (s64)mc_a->counter;
+}
+
+/* Must be called with OVS mutex held. */
+void ovs_flow_masks_rebalance(struct flow_table *table)
+{
+	struct mask_array *ma = rcu_dereference_ovsl(table->mask_array);
+	struct mask_count *masks_and_count;
+	struct mask_array *new;
+	int masks_entries = 0;
+	int i;
+
+	/* Build array of all current entries with use counters. */
+	masks_and_count = kmalloc_objs(*masks_and_count, ma->max);
+	if (!masks_and_count)
+		return;
+
+	for (i = 0; i < ma->max; i++) {
+		struct sw_flow_mask *mask;
+		int cpu;
+
+		mask = rcu_dereference_ovsl(ma->masks[i]);
+		if (unlikely(!mask))
+			break;
+
+		masks_and_count[i].index = i;
+		masks_and_count[i].counter = 0;
+
+		for_each_possible_cpu(cpu) {
+			struct mask_array_stats *stats;
+			unsigned int start;
+			u64 counter;
+
+			stats = per_cpu_ptr(ma->masks_usage_stats, cpu);
+			do {
+				start = u64_stats_fetch_begin(&stats->syncp);
+				counter = stats->usage_cntrs[i];
+			} while (u64_stats_fetch_retry(&stats->syncp, start));
+
+			masks_and_count[i].counter += counter;
+		}
+
+		/* Subtract the zero count value. */
+		masks_and_count[i].counter -= ma->masks_usage_zero_cntr[i];
+
+		/* Rather than calling tbl_mask_array_reset_counters()
+		 * below when no change is needed, do it inline here.
+		 */
+		ma->masks_usage_zero_cntr[i] += masks_and_count[i].counter;
+	}
+
+	if (i == 0)
+		goto free_mask_entries;
+
+	/* Sort the entries */
+	masks_entries = i;
+	sort(masks_and_count, masks_entries, sizeof(*masks_and_count),
+	     compare_mask_and_count, NULL);
+
+	/* If the order is the same, nothing to do... */
+	for (i = 0; i < masks_entries; i++) {
+		if (i != masks_and_count[i].index)
+			break;
+	}
+	if (i == masks_entries)
+		goto free_mask_entries;
+
+	/* Rebuilt the new list in order of usage. */
+	new = tbl_mask_array_alloc(ma->max);
+	if (!new)
+		goto free_mask_entries;
+
+	for (i = 0; i < masks_entries; i++) {
+		int index = masks_and_count[i].index;
+
+		if (ovsl_dereference(ma->masks[index]))
+			new->masks[new->count++] = ma->masks[index];
+	}
+
+	rcu_assign_pointer(table->mask_array, new);
+	call_rcu(&ma->rcu, mask_array_rcu_cb);
+
+free_mask_entries:
+	kfree(masks_and_count);
+}
+
+/* Initializes the flow module.
+ * Returns zero if successful or a negative error code. */
+int ovs_flow_init(void)
+{
+	BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long));
+	BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long));
+
+	flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow)
+				       + (nr_cpu_ids
+					  * sizeof(struct sw_flow_stats *))
+				       + cpumask_size(),
+				       0, 0, NULL);
+	if (flow_cache == NULL)
+		return -ENOMEM;
+
+	flow_stats_cache
+		= kmem_cache_create("sw_flow_stats", sizeof(struct sw_flow_stats),
+				    0, SLAB_HWCACHE_ALIGN, NULL);
+	if (flow_stats_cache == NULL) {
+		kmem_cache_destroy(flow_cache);
+		flow_cache = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/* Uninitializes the flow module. */
+void ovs_flow_exit(void)
+{
+	kmem_cache_destroy(flow_stats_cache);
+	kmem_cache_destroy(flow_cache);
+}