diff options
author | Vlad Buslov <vladbu@mellanox.com> | 2019-08-26 16:44:57 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2019-08-26 14:17:43 -0700 |
commit | 4f8116c85057239ff37519debdd5d45b38ad8130 (patch) | |
tree | 35d4263c8dcf2addf88801cf9e43e49426f1cad7 /net/sched | |
parent | 0846e1616f0f3365cea732e82e2383932fe644e5 (diff) | |
download | linux-4f8116c85057239ff37519debdd5d45b38ad8130.tar.bz2 |
net: sched: protect block offload-related fields with rw_semaphore
In order to remove dependency on rtnl lock, extend tcf_block with 'cb_lock'
rwsem and use it to protect flow_block->cb_list and related counters from
concurrent modification. The lock is taken in read mode for read-only
traversal of cb_list in tc_setup_cb_call() and write mode in all other
cases. This approach ensures that:
- cb_list is not changed concurrently while filters is being offloaded on
block.
- block->nooffloaddevcnt is checked while holding the lock in read mode,
but is only changed by bind/unbind code when holding the cb_lock in write
mode to prevent concurrent modification.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r-- | net/sched/cls_api.c | 45 |
1 files changed, 36 insertions, 9 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index e0d8b456e9f5..959b7ca1ca02 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -568,9 +568,11 @@ static void tc_indr_block_ing_cmd(struct net_device *dev, bo.block = &block->flow_block; + down_write(&block->cb_lock); cb(dev, cb_priv, TC_SETUP_BLOCK, &bo); tcf_block_setup(block, &bo); + up_write(&block->cb_lock); } static struct tcf_block *tc_dev_ingress_block(struct net_device *dev) @@ -661,6 +663,7 @@ static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q, struct net_device *dev = q->dev_queue->dev; int err; + down_write(&block->cb_lock); if (!dev->netdev_ops->ndo_setup_tc) goto no_offload_dev_inc; @@ -669,24 +672,31 @@ static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q, */ if (!tc_can_offload(dev) && tcf_block_offload_in_use(block)) { NL_SET_ERR_MSG(extack, "Bind to offloaded block failed as dev has offload disabled"); - return -EOPNOTSUPP; + err = -EOPNOTSUPP; + goto err_unlock; } err = tcf_block_offload_cmd(block, dev, ei, FLOW_BLOCK_BIND, extack); if (err == -EOPNOTSUPP) goto no_offload_dev_inc; if (err) - return err; + goto err_unlock; tc_indr_block_call(block, dev, ei, FLOW_BLOCK_BIND, extack); + up_write(&block->cb_lock); return 0; no_offload_dev_inc: - if (tcf_block_offload_in_use(block)) - return -EOPNOTSUPP; + if (tcf_block_offload_in_use(block)) { + err = -EOPNOTSUPP; + goto err_unlock; + } + err = 0; block->nooffloaddevcnt++; tc_indr_block_call(block, dev, ei, FLOW_BLOCK_BIND, extack); - return 0; +err_unlock: + up_write(&block->cb_lock); + return err; } static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q, @@ -695,6 +705,7 @@ static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q, struct net_device *dev = q->dev_queue->dev; int err; + down_write(&block->cb_lock); tc_indr_block_call(block, dev, ei, FLOW_BLOCK_UNBIND, NULL); if (!dev->netdev_ops->ndo_setup_tc) @@ -702,10 +713,12 @@ static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q, err = tcf_block_offload_cmd(block, dev, ei, FLOW_BLOCK_UNBIND, NULL); if (err == -EOPNOTSUPP) goto no_offload_dev_dec; + up_write(&block->cb_lock); return; no_offload_dev_dec: WARN_ON(block->nooffloaddevcnt-- == 0); + up_write(&block->cb_lock); } static int @@ -820,6 +833,7 @@ static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q, return ERR_PTR(-ENOMEM); } mutex_init(&block->lock); + init_rwsem(&block->cb_lock); flow_block_init(&block->flow_block); INIT_LIST_HEAD(&block->chain_list); INIT_LIST_HEAD(&block->owner_list); @@ -1355,6 +1369,8 @@ tcf_block_playback_offloads(struct tcf_block *block, flow_setup_cb_t *cb, struct tcf_proto *tp, *tp_prev; int err; + lockdep_assert_held(&block->cb_lock); + for (chain = __tcf_get_next_chain(block, NULL); chain; chain_prev = chain, @@ -1393,6 +1409,8 @@ static int tcf_block_bind(struct tcf_block *block, struct flow_block_cb *block_cb, *next; int err, i = 0; + lockdep_assert_held(&block->cb_lock); + list_for_each_entry(block_cb, &bo->cb_list, list) { err = tcf_block_playback_offloads(block, block_cb->cb, block_cb->cb_priv, true, @@ -1427,6 +1445,8 @@ static void tcf_block_unbind(struct tcf_block *block, { struct flow_block_cb *block_cb, *next; + lockdep_assert_held(&block->cb_lock); + list_for_each_entry_safe(block_cb, next, &bo->cb_list, list) { tcf_block_playback_offloads(block, block_cb->cb, block_cb->cb_priv, false, @@ -2987,19 +3007,26 @@ int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type, int ok_count = 0; int err; + down_read(&block->cb_lock); /* Make sure all netdevs sharing this block are offload-capable. */ - if (block->nooffloaddevcnt && err_stop) - return -EOPNOTSUPP; + if (block->nooffloaddevcnt && err_stop) { + ok_count = -EOPNOTSUPP; + goto err_unlock; + } list_for_each_entry(block_cb, &block->flow_block.cb_list, list) { err = block_cb->cb(type, type_data, block_cb->cb_priv); if (err) { - if (err_stop) - return err; + if (err_stop) { + ok_count = err; + goto err_unlock; + } } else { ok_count++; } } +err_unlock: + up_read(&block->cb_lock); return ok_count; } EXPORT_SYMBOL(tc_setup_cb_call); |