Re: [PATCH 4/6] openvswitch: convert to genradix

From: Matthew Wilcox
Date: Wed May 23 2018 - 07:40:39 EST


On Tue, May 22, 2018 at 09:18:19PM -0400, Kent Overstreet wrote:
> the new generic radix trees have a simpler API and implementation, and
> no limitations on number of elements, so all flex_array users are being
> converted

This doesn't really feel like it should be a flexarray / genradix user.
It just wants to allocate a lot of buckets and use them. Maybe kvmalloc
is the right approach for this user of flexarray?

Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>

net/openvswitch/flow.h | 1 -
net/openvswitch/flow_netlink.h | 1 -
net/openvswitch/flow_table.c | 49 +++++++++++-------------------------------
net/openvswitch/flow_table.h | 3 +--
4 files changed, 13 insertions(+), 41 deletions(-)

diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
index c670dd24b8b7..4f06278166d9 100644
--- a/net/openvswitch/flow.h
+++ b/net/openvswitch/flow.h
@@ -30,7 +30,6 @@
#include <linux/in6.h>
#include <linux/jiffies.h>
#include <linux/time.h>
-#include <linux/flex_array.h>
#include <linux/cpumask.h>
#include <net/inet_ecn.h>
#include <net/ip_tunnels.h>
diff --git a/net/openvswitch/flow_netlink.h b/net/openvswitch/flow_netlink.h
index 6657606b2b47..66f9553758a5 100644
--- a/net/openvswitch/flow_netlink.h
+++ b/net/openvswitch/flow_netlink.h
@@ -30,7 +30,6 @@
#include <linux/in6.h>
#include <linux/jiffies.h>
#include <linux/time.h>
-#include <linux/flex_array.h>

#include <net/inet_ecn.h>
#include <net/ip_tunnels.h>
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 80ea2a71852e..909372bd2621 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -111,29 +111,6 @@ int ovs_flow_tbl_count(const struct flow_table *table)
return table->count;
}

-static struct flex_array *alloc_buckets(unsigned int n_buckets)
-{
- struct flex_array *buckets;
- int i, err;
-
- buckets = flex_array_alloc(sizeof(struct hlist_head),
- n_buckets, GFP_KERNEL);
- if (!buckets)
- return NULL;
-
- err = flex_array_prealloc(buckets, 0, n_buckets, GFP_KERNEL);
- if (err) {
- flex_array_free(buckets);
- return NULL;
- }
-
- for (i = 0; i < n_buckets; i++)
- INIT_HLIST_HEAD((struct hlist_head *)
- flex_array_get(buckets, i));
-
- return buckets;
-}
-
static void flow_free(struct sw_flow *flow)
{
int cpu;
@@ -168,31 +145,30 @@ void ovs_flow_free(struct sw_flow *flow, bool deferred)
flow_free(flow);
}

-static void free_buckets(struct flex_array *buckets)
-{
- flex_array_free(buckets);
-}
-
-
static void __table_instance_destroy(struct table_instance *ti)
{
- free_buckets(ti->buckets);
+ kvfree(ti->buckets);
kfree(ti);
}

static struct table_instance *table_instance_alloc(int new_size)
{
struct table_instance *ti = kmalloc(sizeof(*ti), GFP_KERNEL);
+ int i;

if (!ti)
return NULL;

- ti->buckets = alloc_buckets(new_size);
-
+ ti->buckets = kvmalloc(sizeof(struct hlist_head) * new_size,
+ GFP_KERNEL);
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->keep_flows = false;
@@ -249,7 +225,7 @@ static void table_instance_destroy(struct table_instance *ti,

for (i = 0; i < ti->n_buckets; i++) {
struct sw_flow *flow;
- struct hlist_head *head = flex_array_get(ti->buckets, i);
+ struct hlist_head *head = &ti->buckets[i];
struct hlist_node *n;
int ver = ti->node_ver;
int ufid_ver = ufid_ti->node_ver;
@@ -294,7 +270,7 @@ struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti,
ver = ti->node_ver;
while (*bucket < ti->n_buckets) {
i = 0;
- head = flex_array_get(ti->buckets, *bucket);
+ head = &ti->buckets[*bucket];
hlist_for_each_entry_rcu(flow, head, flow_table.node[ver]) {
if (i < *last) {
i++;
@@ -313,8 +289,7 @@ struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti,
static struct hlist_head *find_bucket(struct table_instance *ti, u32 hash)
{
hash = jhash_1word(hash, ti->hash_seed);
- return flex_array_get(ti->buckets,
- (hash & (ti->n_buckets - 1)));
+ return &ti->buckets[hash & (ti->n_buckets - 1)];
}

static void table_instance_insert(struct table_instance *ti,
@@ -349,7 +324,7 @@ static void flow_table_copy_flows(struct table_instance *old,
struct sw_flow *flow;
struct hlist_head *head;

- head = flex_array_get(old->buckets, i);
+ head = &old->buckets[i];

if (ufid)
hlist_for_each_entry(flow, head,
diff --git a/net/openvswitch/flow_table.h b/net/openvswitch/flow_table.h
index 2dd9900f533d..de5ec6cf5174 100644
--- a/net/openvswitch/flow_table.h
+++ b/net/openvswitch/flow_table.h
@@ -29,7 +29,6 @@
#include <linux/in6.h>
#include <linux/jiffies.h>
#include <linux/time.h>
-#include <linux/flex_array.h>

#include <net/inet_ecn.h>
#include <net/ip_tunnels.h>
@@ -37,7 +36,7 @@
#include "flow.h"

struct table_instance {
- struct flex_array *buckets;
+ struct hlist_head *buckets;
unsigned int n_buckets;
struct rcu_head rcu;
int node_ver;