Update team driver to latest net-next.

Split patches available here:

http://people.redhat.com/jpirko/f18_team_update/

David S. Miller (1):

  team: Revert previous two changes.

Jiri Pirko (25):

  team: make team_mode struct const

  team: for nomode use dummy struct team_mode

  team: add mode priv to port

  team: lb: push hash counting into separate function

  team: allow read/write-only options

  team: introduce array options

  team: comments: s/net\/drivers\/team/drivers\/net\/team/

  team: push array_index and port into separate structure

  team: allow async option changes

  team: fix error path in team_nl_fill_options_get()

  team: fix error path in team_nl_fill_port_list_get()

  team: allow to specify one option instance to be send to userspace

  team: pass NULL to __team_option_inst_add() instead of 0

  team: add port_[enabled/disabled] mode callbacks

  team: lb: introduce infrastructure for userspace driven tx

    loadbalancing

  team: implement multipart netlink messages for options transfers

  team: ensure correct order of netlink messages delivery

  team: allow to send multiple set events in one message

  team: use rcu_dereference_bh() in tx path

  team: use rcu_access_pointer to access RCU pointer by writer

  team: use RCU_INIT_POINTER for NULL assignment of RCU pointer

  team: do RCU update path fixups

  team: fix team_adjust_ops with regard to enabled ports

  team: do not allow to map disabled ports

  team: remove unused rcu_head field from team_port struct

 drivers/net/team/team.c                   |  577 ++++++++++++++++++-----------

 drivers/net/team/team_mode_activebackup.c |   14 +-

 drivers/net/team/team_mode_loadbalance.c  |  543 +++++++++++++++++++++++++--

 drivers/net/team/team_mode_roundrobin.c   |    4 +-

 include/linux/if_team.h                   |   25 +-

 5 files changed, 919 insertions(+), 244 deletions(-)

Signed-off-by: Jiri Pirko <jpirko@redhat.com>

diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c

index c61ae35..5350eea 100644

--- a/drivers/net/team/team.c

+++ b/drivers/net/team/team.c

@@ -1,5 +1,5 @@

 /*

- * net/drivers/team/team.c - Network team device driver

+ * drivers/net/team/team.c - Network team device driver

  * Copyright (c) 2011 Jiri Pirko <jpirko@redhat.com>

  *

  * This program is free software; you can redistribute it and/or modify

@@ -82,14 +82,16 @@ static void team_refresh_port_linkup(struct team_port *port)

 						   port->state.linkup;

 }

+

 /*******************

  * Options handling

  *******************/

 struct team_option_inst { /* One for each option instance */

 	struct list_head list;

+	struct list_head tmp_list;

 	struct team_option *option;

-	struct team_port *port; /* != NULL if per-port */

+	struct team_option_inst_info info;

 	bool changed;

 	bool removed;

 };

@@ -106,22 +108,6 @@ static struct team_option *__team_find_option(struct team *team,

 	return NULL;

 }

-static int __team_option_inst_add(struct team *team, struct team_option *option,

-				  struct team_port *port)

-{

-	struct team_option_inst *opt_inst;

-

-	opt_inst = kmalloc(sizeof(*opt_inst), GFP_KERNEL);

-	if (!opt_inst)

-		return -ENOMEM;

-	opt_inst->option = option;

-	opt_inst->port = port;

-	opt_inst->changed = true;

-	opt_inst->removed = false;

-	list_add_tail(&opt_inst->list, &team->option_inst_list);

-	return 0;

-}

-

 static void __team_option_inst_del(struct team_option_inst *opt_inst)

 {

 	list_del(&opt_inst->list);

@@ -139,14 +125,49 @@ static void __team_option_inst_del_option(struct team *team,

 	}

 }

+static int __team_option_inst_add(struct team *team, struct team_option *option,

+				  struct team_port *port)

+{

+	struct team_option_inst *opt_inst;

+	unsigned int array_size;

+	unsigned int i;

+	int err;

+

+	array_size = option->array_size;

+	if (!array_size)

+		array_size = 1; /* No array but still need one instance */

+

+	for (i = 0; i < array_size; i++) {

+		opt_inst = kmalloc(sizeof(*opt_inst), GFP_KERNEL);

+		if (!opt_inst)

+			return -ENOMEM;

+		opt_inst->option = option;

+		opt_inst->info.port = port;

+		opt_inst->info.array_index = i;

+		opt_inst->changed = true;

+		opt_inst->removed = false;

+		list_add_tail(&opt_inst->list, &team->option_inst_list);

+		if (option->init) {

+			err = option->init(team, &opt_inst->info);

+			if (err)

+				return err;

+		}

+

+	}

+	return 0;

+}

+

 static int __team_option_inst_add_option(struct team *team,

 					 struct team_option *option)

 {

 	struct team_port *port;

 	int err;

-	if (!option->per_port)

-		return __team_option_inst_add(team, option, 0);

+	if (!option->per_port) {

+		err = __team_option_inst_add(team, option, NULL);

+		if (err)

+			goto inst_del_option;

+	}

 	list_for_each_entry(port, &team->port_list, list) {

 		err = __team_option_inst_add(team, option, port);

@@ -180,7 +201,7 @@ static void __team_option_inst_del_port(struct team *team,

 	list_for_each_entry_safe(opt_inst, tmp, &team->option_inst_list, list) {

 		if (opt_inst->option->per_port &&

-		    opt_inst->port == port)

+		    opt_inst->info.port == port)

 			__team_option_inst_del(opt_inst);

 	}

 }

@@ -211,7 +232,7 @@ static void __team_option_inst_mark_removed_port(struct team *team,

 	struct team_option_inst *opt_inst;

 	list_for_each_entry(opt_inst, &team->option_inst_list, list) {

-		if (opt_inst->port == port) {

+		if (opt_inst->info.port == port) {

 			opt_inst->changed = true;

 			opt_inst->removed = true;

 		}

@@ -324,28 +345,12 @@ void team_options_unregister(struct team *team,

 }

 EXPORT_SYMBOL(team_options_unregister);

-static int team_option_port_add(struct team *team, struct team_port *port)

-{

-	int err;

-

-	err = __team_option_inst_add_port(team, port);

-	if (err)

-		return err;

-	__team_options_change_check(team);

-	return 0;

-}

-

-static void team_option_port_del(struct team *team, struct team_port *port)

-{

-	__team_option_inst_mark_removed_port(team, port);

-	__team_options_change_check(team);

-	__team_option_inst_del_port(team, port);

-}

-

 static int team_option_get(struct team *team,

 			   struct team_option_inst *opt_inst,

 			   struct team_gsetter_ctx *ctx)

 {

+	if (!opt_inst->option->getter)

+		return -EOPNOTSUPP;

 	return opt_inst->option->getter(team, ctx);

 }

@@ -353,16 +358,26 @@ static int team_option_set(struct team *team,

 			   struct team_option_inst *opt_inst,

 			   struct team_gsetter_ctx *ctx)

 {

-	int err;

+	if (!opt_inst->option->setter)

+		return -EOPNOTSUPP;

+	return opt_inst->option->setter(team, ctx);

+}

-	err = opt_inst->option->setter(team, ctx);

-	if (err)

-		return err;

+void team_option_inst_set_change(struct team_option_inst_info *opt_inst_info)

+{

+	struct team_option_inst *opt_inst;

+	opt_inst = container_of(opt_inst_info, struct team_option_inst, info);

 	opt_inst->changed = true;

+}

+EXPORT_SYMBOL(team_option_inst_set_change);

+

+void team_options_change_check(struct team *team)

+{

 	__team_options_change_check(team);

-	return err;

 }

+EXPORT_SYMBOL(team_options_change_check);

+

 /****************

  * Mode handling

@@ -371,13 +386,18 @@ static int team_option_set(struct team *team,

 static LIST_HEAD(mode_list);

 static DEFINE_SPINLOCK(mode_list_lock);

-static struct team_mode *__find_mode(const char *kind)

+struct team_mode_item {

+	struct list_head list;

+	const struct team_mode *mode;

+};

+

+static struct team_mode_item *__find_mode(const char *kind)

 {

-	struct team_mode *mode;

+	struct team_mode_item *mitem;

-	list_for_each_entry(mode, &mode_list, list) {

-		if (strcmp(mode->kind, kind) == 0)

-			return mode;

+	list_for_each_entry(mitem, &mode_list, list) {

+		if (strcmp(mitem->mode->kind, kind) == 0)

+			return mitem;

 	}

 	return NULL;

 }

@@ -392,49 +412,65 @@ static bool is_good_mode_name(const char *name)

 	return true;

 }

-int team_mode_register(struct team_mode *mode)

+int team_mode_register(const struct team_mode *mode)

 {

 	int err = 0;

+	struct team_mode_item *mitem;

 	if (!is_good_mode_name(mode->kind) ||

 	    mode->priv_size > TEAM_MODE_PRIV_SIZE)

 		return -EINVAL;

+

+	mitem = kmalloc(sizeof(*mitem), GFP_KERNEL);

+	if (!mitem)

+		return -ENOMEM;

+

 	spin_lock(&mode_list_lock);

 	if (__find_mode(mode->kind)) {

 		err = -EEXIST;

+		kfree(mitem);

 		goto unlock;

 	}

-	list_add_tail(&mode->list, &mode_list);

+	mitem->mode = mode;

+	list_add_tail(&mitem->list, &mode_list);

 unlock:

 	spin_unlock(&mode_list_lock);

 	return err;

 }

 EXPORT_SYMBOL(team_mode_register);

-int team_mode_unregister(struct team_mode *mode)

+void team_mode_unregister(const struct team_mode *mode)

 {

+	struct team_mode_item *mitem;

+

 	spin_lock(&mode_list_lock);

-	list_del_init(&mode->list);

+	mitem = __find_mode(mode->kind);

+	if (mitem) {

+		list_del_init(&mitem->list);

+		kfree(mitem);

+	}

 	spin_unlock(&mode_list_lock);

-	return 0;

 }

 EXPORT_SYMBOL(team_mode_unregister);

-static struct team_mode *team_mode_get(const char *kind)

+static const struct team_mode *team_mode_get(const char *kind)

 {

-	struct team_mode *mode;

+	struct team_mode_item *mitem;

+	const struct team_mode *mode = NULL;

 	spin_lock(&mode_list_lock);

-	mode = __find_mode(kind);

-	if (!mode) {

+	mitem = __find_mode(kind);

+	if (!mitem) {

 		spin_unlock(&mode_list_lock);

 		request_module("team-mode-%s", kind);

 		spin_lock(&mode_list_lock);

-		mode = __find_mode(kind);

+		mitem = __find_mode(kind);

 	}

-	if (mode)

+	if (mitem) {

+		mode = mitem->mode;

 		if (!try_module_get(mode->owner))

 			mode = NULL;

+	}

 	spin_unlock(&mode_list_lock);

 	return mode;

@@ -458,26 +494,45 @@ rx_handler_result_t team_dummy_receive(struct team *team,

 	return RX_HANDLER_ANOTHER;

 }

-static void team_adjust_ops(struct team *team)

+static const struct team_mode __team_no_mode = {

+	.kind		= "*NOMODE*",

+};

+

+static bool team_is_mode_set(struct team *team)

+{

+	return team->mode != &__team_no_mode;

+}

+

+static void team_set_no_mode(struct team *team)

+{

+	team->mode = &__team_no_mode;

+}

+

+static void __team_adjust_ops(struct team *team, int en_port_count)

 {

 	/*

 	 * To avoid checks in rx/tx skb paths, ensure here that non-null and

 	 * correct ops are always set.

 	 */

-	if (list_empty(&team->port_list) ||

-	    !team->mode || !team->mode->ops->transmit)

+	if (!en_port_count || !team_is_mode_set(team) ||

+	    !team->mode->ops->transmit)

 		team->ops.transmit = team_dummy_transmit;

 	else

 		team->ops.transmit = team->mode->ops->transmit;

-	if (list_empty(&team->port_list) ||

-	    !team->mode || !team->mode->ops->receive)

+	if (!en_port_count || !team_is_mode_set(team) ||

+	    !team->mode->ops->receive)

 		team->ops.receive = team_dummy_receive;

 	else

 		team->ops.receive = team->mode->ops->receive;

 }

+static void team_adjust_ops(struct team *team)

+{

+	__team_adjust_ops(team, team->en_port_count);

+}

+

 /*

  * We can benefit from the fact that it's ensured no port is present

  * at the time of mode change. Therefore no packets are in fly so there's no

@@ -487,7 +542,7 @@ static int __team_change_mode(struct team *team,

 			      const struct team_mode *new_mode)

 {

 	/* Check if mode was previously set and do cleanup if so */

-	if (team->mode) {

+	if (team_is_mode_set(team)) {

 		void (*exit_op)(struct team *team) = team->ops.exit;

 		/* Clear ops area so no callback is called any longer */

@@ -497,7 +552,7 @@ static int __team_change_mode(struct team *team,

 		if (exit_op)

 			exit_op(team);

 		team_mode_put(team->mode);

-		team->mode = NULL;

+		team_set_no_mode(team);

 		/* zero private data area */

 		memset(&team->mode_priv, 0,

 		       sizeof(struct team) - offsetof(struct team, mode_priv));

@@ -523,7 +578,7 @@ static int __team_change_mode(struct team *team,

 static int team_change_mode(struct team *team, const char *kind)

 {

-	struct team_mode *new_mode;

+	const struct team_mode *new_mode;

 	struct net_device *dev = team->dev;

 	int err;

@@ -532,7 +587,7 @@ static int team_change_mode(struct team *team, const char *kind)

 		return -EBUSY;

 	}

-	if (team->mode && strcmp(team->mode->kind, kind) == 0) {

+	if (team_is_mode_set(team) && strcmp(team->mode->kind, kind) == 0) {

 		netdev_err(dev, "Unable to change to the same mode the team is in\n");

 		return -EINVAL;

 	}

@@ -559,8 +614,6 @@ static int team_change_mode(struct team *team, const char *kind)

  * Rx path frame handler

  ************************/

-static bool team_port_enabled(struct team_port *port);

-

 /* note: already called with rcu_read_lock */

 static rx_handler_result_t team_handle_frame(struct sk_buff **pskb)

 {

@@ -618,10 +671,11 @@ static bool team_port_find(const struct team *team,

 	return false;

 }

-static bool team_port_enabled(struct team_port *port)

+bool team_port_enabled(struct team_port *port)

 {

 	return port->index != -1;

 }

+EXPORT_SYMBOL(team_port_enabled);

 /*

  * Enable/disable port by adding to enabled port hashlist and setting

@@ -637,6 +691,9 @@ static void team_port_enable(struct team *team,

 	port->index = team->en_port_count++;

 	hlist_add_head_rcu(&port->hlist,

 			   team_port_index_hash(team, port->index));

+	team_adjust_ops(team);

+	if (team->ops.port_enabled)

+		team->ops.port_enabled(team, port);

 }

 static void __reconstruct_port_hlist(struct team *team, int rm_index)

@@ -656,14 +713,20 @@ static void __reconstruct_port_hlist(struct team *team, int rm_index)

 static void team_port_disable(struct team *team,

 			      struct team_port *port)

 {

-	int rm_index = port->index;

-

 	if (!team_port_enabled(port))

 		return;

+	if (team->ops.port_disabled)

+		team->ops.port_disabled(team, port);

 	hlist_del_rcu(&port->hlist);

-	__reconstruct_port_hlist(team, rm_index);

-	team->en_port_count--;

+	__reconstruct_port_hlist(team, port->index);

 	port->index = -1;

+	__team_adjust_ops(team, team->en_port_count - 1);

+	/*

+	 * Wait until readers see adjusted ops. This ensures that

+	 * readers never see team->en_port_count == 0

+	 */

+	synchronize_rcu();

+	team->en_port_count--;

 }

 #define TEAM_VLAN_FEATURES (NETIF_F_ALL_CSUM | NETIF_F_SG | \

@@ -758,7 +821,8 @@ static int team_port_add(struct team *team, struct net_device *port_dev)

 		return -EBUSY;

 	}

-	port = kzalloc(sizeof(struct team_port), GFP_KERNEL);

+	port = kzalloc(sizeof(struct team_port) + team->mode->port_priv_size,

+		       GFP_KERNEL);

 	if (!port)

 		return -ENOMEM;

@@ -809,7 +873,7 @@ static int team_port_add(struct team *team, struct net_device *port_dev)

 		goto err_handler_register;

 	}

-	err = team_option_port_add(team, port);

+	err = __team_option_inst_add_port(team, port);

 	if (err) {

 		netdev_err(dev, "Device %s failed to add per-port options\n",

 			   portname);

@@ -819,9 +883,9 @@ static int team_port_add(struct team *team, struct net_device *port_dev)

 	port->index = -1;

 	team_port_enable(team, port);

 	list_add_tail_rcu(&port->list, &team->port_list);

-	team_adjust_ops(team);

 	__team_compute_features(team);

 	__team_port_change_check(port, !!netif_carrier_ok(port_dev));

+	__team_options_change_check(team);

 	netdev_info(dev, "Port device %s added\n", portname);

@@ -865,12 +929,13 @@ static int team_port_del(struct team *team, struct net_device *port_dev)

 		return -ENOENT;

 	}

+	__team_option_inst_mark_removed_port(team, port);

+	__team_options_change_check(team);

+	__team_option_inst_del_port(team, port);

 	port->removed = true;

 	__team_port_change_check(port, false);

 	team_port_disable(team, port);

 	list_del_rcu(&port->list);

-	team_adjust_ops(team);

-	team_option_port_del(team, port);

 	netdev_rx_handler_unregister(port_dev);

 	netdev_set_master(port_dev, NULL);

 	vlan_vids_del_by_dev(port_dev, dev);

@@ -891,11 +956,9 @@ static int team_port_del(struct team *team, struct net_device *port_dev)

  * Net device ops

  *****************/

-static const char team_no_mode_kind[] = "*NOMODE*";

-

 static int team_mode_option_get(struct team *team, struct team_gsetter_ctx *ctx)

 {

-	ctx->data.str_val = team->mode ? team->mode->kind : team_no_mode_kind;

+	ctx->data.str_val = team->mode->kind;

 	return 0;

 }

@@ -907,39 +970,47 @@ static int team_mode_option_set(struct team *team, struct team_gsetter_ctx *ctx)

 static int team_port_en_option_get(struct team *team,

 				   struct team_gsetter_ctx *ctx)

 {

-	ctx->data.bool_val = team_port_enabled(ctx->port);

+	struct team_port *port = ctx->info->port;

+

+	ctx->data.bool_val = team_port_enabled(port);

 	return 0;

 }

 static int team_port_en_option_set(struct team *team,

 				   struct team_gsetter_ctx *ctx)

 {

+	struct team_port *port = ctx->info->port;

+

 	if (ctx->data.bool_val)

-		team_port_enable(team, ctx->port);

+		team_port_enable(team, port);

 	else

-		team_port_disable(team, ctx->port);

+		team_port_disable(team, port);

 	return 0;

 }

 static int team_user_linkup_option_get(struct team *team,

 				       struct team_gsetter_ctx *ctx)

 {

-	ctx->data.bool_val = ctx->port->user.linkup;

+	struct team_port *port = ctx->info->port;

+

+	ctx->data.bool_val = port->user.linkup;

 	return 0;

 }

 static int team_user_linkup_option_set(struct team *team,

 				       struct team_gsetter_ctx *ctx)

 {

-	ctx->port->user.linkup = ctx->data.bool_val;

-	team_refresh_port_linkup(ctx->port);

+	struct team_port *port = ctx->info->port;

+

+	port->user.linkup = ctx->data.bool_val;

+	team_refresh_port_linkup(port);

 	return 0;

 }

 static int team_user_linkup_en_option_get(struct team *team,

 					  struct team_gsetter_ctx *ctx)

 {

-	struct team_port *port = ctx->port;

+	struct team_port *port = ctx->info->port;

 	ctx->data.bool_val = port->user.linkup_enabled;

 	return 0;

@@ -948,10 +1019,10 @@ static int team_user_linkup_en_option_get(struct team *team,

 static int team_user_linkup_en_option_set(struct team *team,

 					  struct team_gsetter_ctx *ctx)

 {

-	struct team_port *port = ctx->port;

+	struct team_port *port = ctx->info->port;

 	port->user.linkup_enabled = ctx->data.bool_val;

-	team_refresh_port_linkup(ctx->port);

+	team_refresh_port_linkup(port);

 	return 0;

 }

@@ -993,6 +1064,7 @@ static int team_init(struct net_device *dev)

 	team->dev = dev;

 	mutex_init(&team->lock);

+	team_set_no_mode(team);

 	team->pcpu_stats = alloc_percpu(struct team_pcpu_stats);

 	if (!team->pcpu_stats)

@@ -1482,16 +1554,128 @@ err_fill:

 	return err;

 }

-static int team_nl_fill_options_get(struct sk_buff *skb,

-				    u32 pid, u32 seq, int flags,

-				    struct team *team, bool fillall)

+typedef int team_nl_send_func_t(struct sk_buff *skb,

+				struct team *team, u32 pid);

+

+static int team_nl_send_unicast(struct sk_buff *skb, struct team *team, u32 pid)

+{

+	return genlmsg_unicast(dev_net(team->dev), skb, pid);

+}

+

+static int team_nl_fill_one_option_get(struct sk_buff *skb, struct team *team,

+				       struct team_option_inst *opt_inst)

+{

+	struct nlattr *option_item;

+	struct team_option *option = opt_inst->option;

+	struct team_option_inst_info *opt_inst_info = &opt_inst->info;

+	struct team_gsetter_ctx ctx;

+	int err;

+

+	ctx.info = opt_inst_info;

+	err = team_option_get(team, opt_inst, &ctx;;

+	if (err)

+		return err;

+

+	option_item = nla_nest_start(skb, TEAM_ATTR_ITEM_OPTION);

+	if (!option_item)

+		return -EMSGSIZE;

+

+	if (nla_put_string(skb, TEAM_ATTR_OPTION_NAME, option->name))

+		goto nest_cancel;

+	if (opt_inst_info->port &&

+	    nla_put_u32(skb, TEAM_ATTR_OPTION_PORT_IFINDEX,

+			opt_inst_info->port->dev->ifindex))

+		goto nest_cancel;

+	if (opt_inst->option->array_size &&

+	    nla_put_u32(skb, TEAM_ATTR_OPTION_ARRAY_INDEX,

+			opt_inst_info->array_index))

+		goto nest_cancel;

+

+	switch (option->type) {

+	case TEAM_OPTION_TYPE_U32:

+		if (nla_put_u8(skb, TEAM_ATTR_OPTION_TYPE, NLA_U32))

+			goto nest_cancel;

+		if (nla_put_u32(skb, TEAM_ATTR_OPTION_DATA, ctx.data.u32_val))

+			goto nest_cancel;

+		break;

+	case TEAM_OPTION_TYPE_STRING:

+		if (nla_put_u8(skb, TEAM_ATTR_OPTION_TYPE, NLA_STRING))

+			goto nest_cancel;

+		if (nla_put_string(skb, TEAM_ATTR_OPTION_DATA,

+				   ctx.data.str_val))

+			goto nest_cancel;

+		break;

+	case TEAM_OPTION_TYPE_BINARY:

+		if (nla_put_u8(skb, TEAM_ATTR_OPTION_TYPE, NLA_BINARY))

+			goto nest_cancel;

+		if (nla_put(skb, TEAM_ATTR_OPTION_DATA, ctx.data.bin_val.len,

+			    ctx.data.bin_val.ptr))

+			goto nest_cancel;

+		break;

+	case TEAM_OPTION_TYPE_BOOL:

+		if (nla_put_u8(skb, TEAM_ATTR_OPTION_TYPE, NLA_FLAG))

+			goto nest_cancel;

+		if (ctx.data.bool_val &&

+		    nla_put_flag(skb, TEAM_ATTR_OPTION_DATA))

+			goto nest_cancel;

+		break;

+	default:

+		BUG();

+	}

+	if (opt_inst->removed && nla_put_flag(skb, TEAM_ATTR_OPTION_REMOVED))

+		goto nest_cancel;

+	if (opt_inst->changed) {

+		if (nla_put_flag(skb, TEAM_ATTR_OPTION_CHANGED))

+			goto nest_cancel;

+		opt_inst->changed = false;

+	}

+	nla_nest_end(skb, option_item);

+	return 0;

+

+nest_cancel:

+	nla_nest_cancel(skb, option_item);

+	return -EMSGSIZE;

+}

+

+static int __send_and_alloc_skb(struct sk_buff **pskb,

+				struct team *team, u32 pid,

+				team_nl_send_func_t *send_func)

+{

+	int err;

+

+	if (*pskb) {

+		err = send_func(*pskb, team, pid);

+		if (err)

+			return err;

+	}

+	*pskb = genlmsg_new(NLMSG_DEFAULT_SIZE - GENL_HDRLEN, GFP_KERNEL);

+	if (!*pskb)

+		return -ENOMEM;

+	return 0;