diff mbox series

[wpan-next,v3,08/11] net: mac802154: Introduce a tx queue flushing mechanism

Message ID 20220517163450.240299-9-miquel.raynal@bootlin.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series ieee802154: Synchronous Tx support | expand

Checks

Context Check Description
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 7 this patch: 7
netdev/cc_maintainers warning 1 maintainers not CCed: edumazet@google.com
netdev/build_clang success Errors and warnings before: 4 this patch: 4
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 7 this patch: 7
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 6 this patch: 6
netdev/source_inline success Was 0 now: 0
netdev/tree_selection success Guessing tree name failed - patch did not apply, async

Commit Message

Miquel Raynal May 17, 2022, 4:34 p.m. UTC 
Right now we are able to stop a queue but we have no indication if a
transmission is ongoing or not.

Thanks to recent additions, we can track the number of ongoing
transmissions so we know if the last transmission is over. Adding on top
of it an internal wait queue also allows to be woken up asynchronously
when this happens. If, beforehands, we marked the queue to be held and
stopped it, we end up flushing and stopping the tx queue.

Thanks to this feature, we will soon be able to introduce a synchronous
transmit API.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 include/net/cfg802154.h      |  1 +
 net/ieee802154/core.c        |  1 +
 net/mac802154/cfg.c          |  2 +-
 net/mac802154/ieee802154_i.h |  1 +
 net/mac802154/tx.c           | 26 ++++++++++++++++++++++++--
 net/mac802154/util.c         |  6 ++++--
 6 files changed, 32 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/include/net/cfg802154.h b/include/net/cfg802154.h
index 7a191418f258..8881b6126b58 100644
--- a/include/net/cfg802154.h
+++ b/include/net/cfg802154.h
@@ -218,6 +218,7 @@  struct wpan_phy {
 	spinlock_t queue_lock;
 	atomic_t ongoing_txs;
 	atomic_t hold_txs;
+	wait_queue_head_t sync_txq;
 
 	char priv[] __aligned(NETDEV_ALIGN);
 };
diff --git a/net/ieee802154/core.c b/net/ieee802154/core.c
index 47a4de6df88b..57546e07e06a 100644
--- a/net/ieee802154/core.c
+++ b/net/ieee802154/core.c
@@ -129,6 +129,7 @@  wpan_phy_new(const struct cfg802154_ops *ops, size_t priv_size)
 	wpan_phy_net_set(&rdev->wpan_phy, &init_net);
 
 	init_waitqueue_head(&rdev->dev_wait);
+	init_waitqueue_head(&rdev->wpan_phy.sync_txq);
 
 	spin_lock_init(&rdev->wpan_phy.queue_lock);
 
diff --git a/net/mac802154/cfg.c b/net/mac802154/cfg.c
index b51100fd9e3f..93df24f75572 100644
--- a/net/mac802154/cfg.c
+++ b/net/mac802154/cfg.c
@@ -46,7 +46,7 @@  static int ieee802154_suspend(struct wpan_phy *wpan_phy)
 	if (!local->open_count)
 		goto suspend;
 
-	ieee802154_hold_queue(local);
+	ieee802154_sync_and_hold_queue(local);
 	synchronize_net();
 
 	/* stop hardware - this must stop RX */
diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index e34db1d49ef4..a057827fc48a 100644
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -124,6 +124,7 @@  extern struct ieee802154_mlme_ops mac802154_mlme_wpan;
 
 void ieee802154_rx(struct ieee802154_local *local, struct sk_buff *skb);
 void ieee802154_xmit_sync_worker(struct work_struct *work);
+int ieee802154_sync_and_hold_queue(struct ieee802154_local *local);
 netdev_tx_t
 ieee802154_monitor_start_xmit(struct sk_buff *skb, struct net_device *dev);
 netdev_tx_t
diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index 607019b8f8ab..38f74b8b6740 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -44,7 +44,8 @@  void ieee802154_xmit_sync_worker(struct work_struct *work)
 err_tx:
 	/* Restart the netif queue on each sub_if_data object. */
 	ieee802154_release_queue(local);
-	atomic_dec(&local->phy->ongoing_txs);
+	if (!atomic_dec_and_test(&local->phy->ongoing_txs))
+		wake_up(&local->phy->sync_txq);
 	kfree_skb(skb);
 	netdev_dbg(dev, "transmission failed\n");
 }
@@ -100,12 +101,33 @@  ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
 
 err_wake_netif_queue:
 	ieee802154_release_queue(local);
-	atomic_dec(&local->phy->ongoing_txs);
+	if (!atomic_dec_and_test(&local->phy->ongoing_txs))
+		wake_up(&local->phy->sync_txq);
 err_free_skb:
 	kfree_skb(skb);
 	return NETDEV_TX_OK;
 }
 
+static int ieee802154_sync_queue(struct ieee802154_local *local)
+{
+	int ret;
+
+	ieee802154_hold_queue(local);
+	ieee802154_disable_queue(local);
+	wait_event(local->phy->sync_txq, !atomic_read(&local->phy->ongoing_txs));
+	ret = local->tx_result;
+	ieee802154_release_queue(local);
+
+	return ret;
+}
+
+int ieee802154_sync_and_hold_queue(struct ieee802154_local *local)
+{
+	ieee802154_hold_queue(local);
+
+	return ieee802154_sync_queue(local);
+}
+
 static netdev_tx_t
 ieee802154_hot_tx(struct ieee802154_local *local, struct sk_buff *skb)
 {
diff --git a/net/mac802154/util.c b/net/mac802154/util.c
index 02645f57fc2a..cddb42984484 100644
--- a/net/mac802154/util.c
+++ b/net/mac802154/util.c
@@ -140,7 +140,8 @@  void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb,
 	}
 
 	dev_consume_skb_any(skb);
-	atomic_dec(&hw->phy->ongoing_txs);
+	if (!atomic_dec_and_test(&hw->phy->ongoing_txs))
+		wake_up(&hw->phy->sync_txq);
 }
 EXPORT_SYMBOL(ieee802154_xmit_complete);
 
@@ -152,7 +153,8 @@  void ieee802154_xmit_error(struct ieee802154_hw *hw, struct sk_buff *skb,
 	local->tx_result = reason;
 	ieee802154_release_queue(local);
 	dev_kfree_skb_any(skb);
-	atomic_dec(&hw->phy->ongoing_txs);
+	if (!atomic_dec_and_test(&hw->phy->ongoing_txs))
+		wake_up(&hw->phy->sync_txq);
 }
 EXPORT_SYMBOL(ieee802154_xmit_error);