[PATCH net 15/16] can: rx-offload: add IRQ queue flush predicate

[Marc Kleine-Budde <mkl@pengutronix.de>]

From: Chris Strong <chris.strong@flocksafety.com>

Drivers that queue received SKBs from a threaded interrupt may need to
publish a partial batch before the handler returns. The existing overflow
check covers only the NAPI-visible queue after the IRQ-local queue has been
spliced, so it cannot guide that decision.

Add can_rx_offload_irq_queue_needs_flush() to report when the IRQ-local
queue reaches the NAPI poll weight. Keep the query separate from the flush
operation so callers can finish processing related interrupt sources before
publishing the batch.

Assisted-by: LLM
Signed-off-by: Chris Strong <chris.strong@flocksafety.com>
Link: https://patch.msgid.link/20260929-upstream-can-rx-offload-batching-v2-1-3b587c519f5d@flocksafety.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 include/linux/can/rx-offload.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/can/rx-offload.h b/include/linux/can/rx-offload.h
index d29bb4521947..f9b9474f7190 100644
--- a/include/linux/can/rx-offload.h
+++ b/include/linux/can/rx-offload.h
@@ -62,4 +62,11 @@ static inline void can_rx_offload_disable(struct can_rx_offload *offload)
 	napi_disable(&offload->napi);
 }
 
+static inline bool
+can_rx_offload_irq_queue_needs_flush(const struct can_rx_offload *offload)
+{
+	/* skb_irq_queue is owned by the interrupt context queuing the SKBs. */
+	return skb_queue_len(&offload->skb_irq_queue) >= offload->napi.weight;
+}
+
 #endif /* !_CAN_RX_OFFLOAD_H */
-- 
2.53.0