diff mbox series

[v3,16/41] net: mac802154: Explain the use of ieee802154_wake/stop_queue()

Message ID 20220117115440.60296-17-miquel.raynal@bootlin.com (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series IEEE 802.15.4 scan support | expand

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netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count fail Series longer than 15 patches (and no cover letter)
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/cc_maintainers warning 1 maintainers not CCed: davem@davemloft.net
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
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netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 3 this patch: 3
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 24 lines checked
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netdev/source_inline success Was 0 now: 0
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Commit Message

Miquel Raynal Jan. 17, 2022, 11:54 a.m. UTC
It is not straightforward to the newcomer that a single skb can be sent
at a time and that the internal process is to stop the queue when
processing a frame before re-enabling it. Make this clear by documenting
the ieee802154_wake/stop_queue() helpers.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 include/net/mac802154.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)
diff mbox series

Patch

diff --git a/include/net/mac802154.h b/include/net/mac802154.h
index d524ffb9eb25..94b2e3008e77 100644
--- a/include/net/mac802154.h
+++ b/include/net/mac802154.h
@@ -464,6 +464,12 @@  void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb,
  * ieee802154_wake_queue - wake ieee802154 queue
  * @hw: pointer as obtained from ieee802154_alloc_hw().
  *
+ * Tranceivers have either one transmit framebuffer or one framebuffer for both
+ * transmitting and receiving. Hence, the core only handles one frame at a time
+ * for each phy, which means we had to stop the queue to avoid new skb to come
+ * during the transmission. The queue then needs to be woken up after the
+ * operation.
+ *
  * Drivers should use this function instead of netif_wake_queue.
  */
 void ieee802154_wake_queue(struct ieee802154_hw *hw);
@@ -472,6 +478,12 @@  void ieee802154_wake_queue(struct ieee802154_hw *hw);
  * ieee802154_stop_queue - stop ieee802154 queue
  * @hw: pointer as obtained from ieee802154_alloc_hw().
  *
+ * Tranceivers have either one transmit framebuffer or one framebuffer for both
+ * transmitting and receiving. Hence, the core only handles one frame at a time
+ * for each phy, which means we need to tell upper layers to stop giving us new
+ * skbs while we are busy with the transmitted one. The queue must then be
+ * stopped before transmitting.
+ *
  * Drivers should use this function instead of netif_stop_queue.
  */
 void ieee802154_stop_queue(struct ieee802154_hw *hw);