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net: sched: Avoid implicit chain 0 creation
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Currently, chain 0 is implicitly created during block creation. However
that does not align with chain object exposure, creation and destruction
api introduced later on. So make the chain 0 behave the same way as any
other chain and only create it when it is needed. Since chain 0 is
somehow special as the qdiscs need to hold pointer to the first chain
tp, this requires to move the chain head change callback infra to the
block structure.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jiri Pirko authored and David S. Miller committed Jul 24, 2018
1 parent f34e8bf commit f71e0ca
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Showing 2 changed files with 43 additions and 48 deletions.
5 changes: 4 additions & 1 deletion include/net/sch_generic.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -300,7 +300,6 @@ typedef void tcf_chain_head_change_t(struct tcf_proto *tp_head, void *priv);

struct tcf_chain {
struct tcf_proto __rcu *filter_chain;
struct list_head filter_chain_list;
struct list_head list;
struct tcf_block *block;
u32 index; /* chain index */
Expand All @@ -318,6 +317,10 @@ struct tcf_block {
bool keep_dst;
unsigned int offloadcnt; /* Number of oddloaded filters */
unsigned int nooffloaddevcnt; /* Number of devs unable to do offload */
struct {
struct tcf_chain *chain;
struct list_head filter_chain_list;
} chain0;
};

static inline void tcf_block_offload_inc(struct tcf_block *block, u32 *flags)
Expand Down
86 changes: 39 additions & 47 deletions net/sched/cls_api.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -204,11 +204,12 @@ static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
chain = kzalloc(sizeof(*chain), GFP_KERNEL);
if (!chain)
return NULL;
INIT_LIST_HEAD(&chain->filter_chain_list);
list_add_tail(&chain->list, &block->chain_list);
chain->block = block;
chain->index = chain_index;
chain->refcnt = 1;
if (!chain->index)
block->chain0.chain = chain;
return chain;
}

Expand All @@ -218,20 +219,24 @@ static void tcf_chain_head_change_item(struct tcf_filter_chain_list_item *item,
if (item->chain_head_change)
item->chain_head_change(tp_head, item->chain_head_change_priv);
}
static void tcf_chain_head_change(struct tcf_chain *chain,
struct tcf_proto *tp_head)

static void tcf_chain0_head_change(struct tcf_chain *chain,
struct tcf_proto *tp_head)
{
struct tcf_filter_chain_list_item *item;
struct tcf_block *block = chain->block;

list_for_each_entry(item, &chain->filter_chain_list, list)
if (chain->index)
return;
list_for_each_entry(item, &block->chain0.filter_chain_list, list)
tcf_chain_head_change_item(item, tp_head);
}

static void tcf_chain_flush(struct tcf_chain *chain)
{
struct tcf_proto *tp = rtnl_dereference(chain->filter_chain);

tcf_chain_head_change(chain, NULL);
tcf_chain0_head_change(chain, NULL);
while (tp) {
RCU_INIT_POINTER(chain->filter_chain, tp->next);
tcf_proto_destroy(tp, NULL);
Expand All @@ -245,8 +250,10 @@ static void tcf_chain_destroy(struct tcf_chain *chain)
struct tcf_block *block = chain->block;

list_del(&chain->list);
if (!chain->index)
block->chain0.chain = NULL;
kfree(chain);
if (list_empty(&block->chain_list))
if (list_empty(&block->chain_list) && block->refcnt == 0)
kfree(block);
}

Expand Down Expand Up @@ -346,10 +353,11 @@ static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q,
}

static int
tcf_chain_head_change_cb_add(struct tcf_chain *chain,
struct tcf_block_ext_info *ei,
struct netlink_ext_ack *extack)
tcf_chain0_head_change_cb_add(struct tcf_block *block,
struct tcf_block_ext_info *ei,
struct netlink_ext_ack *extack)
{
struct tcf_chain *chain0 = block->chain0.chain;
struct tcf_filter_chain_list_item *item;

item = kmalloc(sizeof(*item), GFP_KERNEL);
Expand All @@ -359,23 +367,25 @@ tcf_chain_head_change_cb_add(struct tcf_chain *chain,
}
item->chain_head_change = ei->chain_head_change;
item->chain_head_change_priv = ei->chain_head_change_priv;
if (chain->filter_chain)
tcf_chain_head_change_item(item, chain->filter_chain);
list_add(&item->list, &chain->filter_chain_list);
if (chain0 && chain0->filter_chain)
tcf_chain_head_change_item(item, chain0->filter_chain);
list_add(&item->list, &block->chain0.filter_chain_list);
return 0;
}

static void
tcf_chain_head_change_cb_del(struct tcf_chain *chain,
struct tcf_block_ext_info *ei)
tcf_chain0_head_change_cb_del(struct tcf_block *block,
struct tcf_block_ext_info *ei)
{
struct tcf_chain *chain0 = block->chain0.chain;
struct tcf_filter_chain_list_item *item;

list_for_each_entry(item, &chain->filter_chain_list, list) {
list_for_each_entry(item, &block->chain0.filter_chain_list, list) {
if ((!ei->chain_head_change && !ei->chain_head_change_priv) ||
(item->chain_head_change == ei->chain_head_change &&
item->chain_head_change_priv == ei->chain_head_change_priv)) {
tcf_chain_head_change_item(item, NULL);
if (chain0)
tcf_chain_head_change_item(item, NULL);
list_del(&item->list);
kfree(item);
return;
Expand Down Expand Up @@ -411,8 +421,6 @@ static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
struct netlink_ext_ack *extack)
{
struct tcf_block *block;
struct tcf_chain *chain;
int err;

block = kzalloc(sizeof(*block), GFP_KERNEL);
if (!block) {
Expand All @@ -422,14 +430,8 @@ static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
INIT_LIST_HEAD(&block->chain_list);
INIT_LIST_HEAD(&block->cb_list);
INIT_LIST_HEAD(&block->owner_list);
INIT_LIST_HEAD(&block->chain0.filter_chain_list);

/* Create chain 0 by default, it has to be always present. */
chain = tcf_chain_create(block, 0);
if (!chain) {
NL_SET_ERR_MSG(extack, "Failed to create new tcf chain");
err = -ENOMEM;
goto err_chain_create;
}
block->refcnt = 1;
block->net = net;
block->index = block_index;
Expand All @@ -438,10 +440,6 @@ static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
if (!tcf_block_shared(block))
block->q = q;
return block;

err_chain_create:
kfree(block);
return ERR_PTR(err);
}

static struct tcf_block *tcf_block_lookup(struct net *net, u32 block_index)
Expand Down Expand Up @@ -523,11 +521,6 @@ static struct tcf_block *tcf_block_find(struct net *net, struct Qdisc **q,
return block;
}

static struct tcf_chain *tcf_block_chain_zero(struct tcf_block *block)
{
return list_first_entry(&block->chain_list, struct tcf_chain, list);
}

struct tcf_block_owner_item {
struct list_head list;
struct Qdisc *q;
Expand Down Expand Up @@ -621,10 +614,9 @@ int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,

tcf_block_owner_netif_keep_dst(block, q, ei->binder_type);

err = tcf_chain_head_change_cb_add(tcf_block_chain_zero(block),
ei, extack);
err = tcf_chain0_head_change_cb_add(block, ei, extack);
if (err)
goto err_chain_head_change_cb_add;
goto err_chain0_head_change_cb_add;

err = tcf_block_offload_bind(block, q, ei, extack);
if (err)
Expand All @@ -634,15 +626,14 @@ int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
return 0;

err_block_offload_bind:
tcf_chain_head_change_cb_del(tcf_block_chain_zero(block), ei);
err_chain_head_change_cb_add:
tcf_chain0_head_change_cb_del(block, ei);
err_chain0_head_change_cb_add:
tcf_block_owner_del(block, q, ei->binder_type);
err_block_owner_add:
if (created) {
if (tcf_block_shared(block))
tcf_block_remove(block, net);
err_block_insert:
kfree(tcf_block_chain_zero(block));
kfree(block);
} else {
block->refcnt--;
Expand Down Expand Up @@ -682,10 +673,10 @@ void tcf_block_put_ext(struct tcf_block *block, struct Qdisc *q,

if (!block)
return;
tcf_chain_head_change_cb_del(tcf_block_chain_zero(block), ei);
tcf_chain0_head_change_cb_del(block, ei);
tcf_block_owner_del(block, q, ei->binder_type);

if (--block->refcnt == 0) {
if (block->refcnt == 1) {
if (tcf_block_shared(block))
tcf_block_remove(block, block->net);

Expand All @@ -701,13 +692,14 @@ void tcf_block_put_ext(struct tcf_block *block, struct Qdisc *q,

tcf_block_offload_unbind(block, q, ei);

if (block->refcnt == 0) {
if (block->refcnt == 1) {
/* At this point, all the chains should have refcnt >= 1. */
list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
tcf_chain_put(chain);

/* Finally, put chain 0 and allow block to be freed. */
tcf_chain_put(tcf_block_chain_zero(block));
block->refcnt--;
if (list_empty(&block->chain_list))
kfree(block);
}
}
EXPORT_SYMBOL(tcf_block_put_ext);
Expand Down Expand Up @@ -947,7 +939,7 @@ static void tcf_chain_tp_insert(struct tcf_chain *chain,
struct tcf_proto *tp)
{
if (*chain_info->pprev == chain->filter_chain)
tcf_chain_head_change(chain, tp);
tcf_chain0_head_change(chain, tp);
RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain_info));
rcu_assign_pointer(*chain_info->pprev, tp);
tcf_chain_hold(chain);
Expand All @@ -960,7 +952,7 @@ static void tcf_chain_tp_remove(struct tcf_chain *chain,
struct tcf_proto *next = rtnl_dereference(chain_info->next);

if (tp == chain->filter_chain)
tcf_chain_head_change(chain, next);
tcf_chain0_head_change(chain, next);
RCU_INIT_POINTER(*chain_info->pprev, next);
tcf_chain_put(chain);
}
Expand Down

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