datapath: convert to kvmalloc

Upstream commit:
    commit ee9c5e67557f9663b27946ba1d3813fb1924b1fe
    Author: Kent Overstreet <[email protected]>
    Date:   Mon Mar 11 23:31:02 2019 -0700

    openvswitch: convert to kvmalloc

    Patch series "generic radix trees; drop flex arrays".

    This patch (of 7):

    There was no real need for this code to be using flexarrays, it's just
    implementing a hash table - ideally it would be using rhashtables, but
    that conversion would be significantly more complicated.

    Link: http://lkml.kernel.org/r/[email protected]
    Signed-off-by: Kent Overstreet <[email protected]>
    Reviewed-by: Matthew Wilcox <[email protected]>
    Cc: Pravin B Shelar <[email protected]>
    Cc: Alexey Dobriyan <[email protected]>
    Cc: Al Viro <[email protected]>
    Cc: Dave Hansen <[email protected]>
    Cc: Eric Paris <[email protected]>
    Cc: Marcelo Ricardo Leitner <[email protected]>
    Cc: Neil Horman <[email protected]>
    Cc: Paul Moore <[email protected]>
    Cc: Shaohua Li <[email protected]>
    Cc: Stephen Smalley <[email protected]>
    Cc: Vlad Yasevich <[email protected]>
    Signed-off-by: Andrew Morton <[email protected]>
    Signed-off-by: Linus Torvalds <[email protected]>

Cc: Kent Overstreet <[email protected]>
Reviewed-by: Yifeng Sun <[email protected]>
Signed-off-by: Greg Rose <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>

datapath/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>

datapath/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>

datapath/flow_table.c

@@ -117,29 +117,6 @@ 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;
@@ -174,31 +151,30 @@ 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_array(new_size, sizeof(struct hlist_head),
+				     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;
@@ -319,7 +295,7 @@ 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;
@@ -366,7 +342,7 @@ 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++;
@@ -385,8 +361,7 @@ 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,
@@ -419,9 +394,7 @@ static void flow_table_copy_flows(struct table_instance *old,
 	/* Insert in new table. */
 	for (i = 0; i < old->n_buckets; i++) {
 		struct sw_flow *flow;
-		struct hlist_head *head;
-
-		head = flex_array_get(old->buckets, i);
+		struct hlist_head *head = &old->buckets[i];
 
 		if (ufid)
 			hlist_for_each_entry(flow, head,

datapath/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>
@@ -48,7 +47,7 @@ struct mask_array {
 };
 
 struct table_instance {
-	struct flex_array *buckets;
+	struct hlist_head *buckets;
 	unsigned int n_buckets;
 	struct rcu_head rcu;
 	int node_ver;