diff mbox series

[wpan-next,v4,07/11] net: mac802154: Introduce a helper to disable the queue

Message ID 20220519150516.443078-8-miquel.raynal@bootlin.com (mailing list archive)
State Awaiting Upstream
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: 4 this patch: 4
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: 4 this patch: 4
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 38 lines checked
netdev/kdoc success Errors and warnings before: 4 this patch: 4
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 19, 2022, 3:05 p.m. UTC
Sometimes calling the stop queue helper is not enough because it does
not hold any lock. In order to be safe and avoid racy situations when
trying to (soon) sync the Tx queue, for instance before sending an MLME
frame, let's now introduce an helper which actually hold the necessary
locks when doing so.

Suggested-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 net/mac802154/ieee802154_i.h | 12 ++++++++++++
 net/mac802154/util.c         | 14 ++++++++++++++
 2 files changed, 26 insertions(+)
diff mbox series

Patch

diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index 0c7ff9e0b632..e34db1d49ef4 100644
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -149,6 +149,18 @@  void ieee802154_hold_queue(struct ieee802154_local *local);
  */
 void ieee802154_release_queue(struct ieee802154_local *local);
 
+/**
+ * ieee802154_disable_queue - disable ieee802154 queue
+ * @local: main mac object
+ *
+ * When trying to sync the Tx queue, we cannot just stop the queue
+ * (which is basically a bit being set without proper lock handling)
+ * because it would be racy. We actually need to call netif_tx_disable()
+ * instead, which is done by this helper. Restarting the queue can
+ * however still be done with a regular wake call.
+ */
+void ieee802154_disable_queue(struct ieee802154_local *local);
+
 /* MIB callbacks */
 void mac802154_dev_set_page_channel(struct net_device *dev, u8 page, u8 chan);
 
diff --git a/net/mac802154/util.c b/net/mac802154/util.c
index 0ed8b5bcbe8a..999534f64485 100644
--- a/net/mac802154/util.c
+++ b/net/mac802154/util.c
@@ -83,6 +83,20 @@  void ieee802154_release_queue(struct ieee802154_local *local)
 	spin_unlock_irqrestore(&local->phy->queue_lock, flags);
 }
 
+void ieee802154_disable_queue(struct ieee802154_local *local)
+{
+	struct ieee802154_sub_if_data *sdata;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+		if (!sdata->dev)
+			continue;
+
+		netif_tx_disable(sdata->dev);
+	}
+	rcu_read_unlock();
+}
+
 enum hrtimer_restart ieee802154_xmit_ifs_timer(struct hrtimer *timer)
 {
 	struct ieee802154_local *local =