Merge branch 'net-atlantic-fix-two-ring-teardown-leaks'

Yangyu Chen says:

====================
net: atlantic: fix two ring teardown leaks

These are the two fixes from the page_pool conversion series [1],
resent against net as requested in the review of that series. The
page_pool conversion itself stays in net-next and is not part of this
posting; it depends on these fixes, but they stand on their own.

Both patches are unchanged from [1] apart from the collected
Reviewed-by tags, and each carries a Fixes tag and a Cc: stable with
the affected range (patch 1: v4.11+, patch 2: v5.2+). They apply and
were build- and runtime-tested independently of each other and of the
conversion.

Patch 1: aq_vec_deinit() drains the TX rings with a single
aq_ring_tx_clean() call, which is capped at AQ_CFG_TX_CLEAN_BUDGET
descriptors and stops at hw_head, frozen once the hardware and NAPI
have been stopped. Everything beyond that keeps its skb or xdp_frame
when the interface goes down and is lost when the buffer ring is
freed.

Patch 2: aq_ring_rx_deinit() only walks [sw_head, sw_tail). Since the
page reuse strategy was added, a cleaned RX buffer keeps its page for
reuse and refill is batched, so consumed but not yet reposted slots
accumulate in the [sw_tail, sw_head) gap and their pages and DMA
mappings are never released.

Reproduction logs for both leaks (as page_pool stalled shutdowns,
which is how they become visible) are in the notes of the respective
patches.

[1] https://lore.kernel.org/lkml/tencent_1F173E0FC1606D2AC704DC9C98AF10984607@qq.com/
====================

Link: https://patch.msgid.link/tencent_29B860317921D68DE77C718242DA418EB608@qq.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/aquantia/atlantic/aq_ring.c

@@ -360,6 +360,35 @@ bool aq_ring_tx_clean(struct aq_ring_s *self)
 	return !!budget;
 }
 
+void aq_ring_tx_deinit(struct aq_ring_s *self)
+{
+	if (!self)
+		return;
+
+	for (; self->sw_head != self->sw_tail;
+		self->sw_head = aq_ring_next_dx(self, self->sw_head)) {
+		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
+		struct device *ndev = aq_nic_get_dev(self->aq_nic);
+
+		if (buff->is_mapped) {
+			if (buff->is_sop) {
+				dma_unmap_single(ndev, buff->pa, buff->len,
+						 DMA_TO_DEVICE);
+			} else {
+				dma_unmap_page(ndev, buff->pa, buff->len,
+					       DMA_TO_DEVICE);
+			}
+		}
+
+		if (buff->is_eop) {
+			if (buff->skb)
+				dev_kfree_skb_any(buff->skb);
+			else if (buff->xdpf)
+				xdp_return_frame(buff->xdpf);
+		}
+	}
+}
+
 static void aq_rx_checksum(struct aq_ring_s *self,
 			   struct aq_ring_buff_s *buff,
 			   struct sk_buff *skb)
@@ -921,15 +950,29 @@ int aq_ring_rx_fill(struct aq_ring_s *self)
 
 void aq_ring_rx_deinit(struct aq_ring_s *self)
 {
-	if (!self)
+	unsigned int i;
+
+	if (!self || !self->buff_ring)
 		return;
 
-	for (; self->sw_head != self->sw_tail;
-		self->sw_head = aq_ring_next_dx(self, self->sw_head)) {
-		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
+	/* Release every page still owned by the ring.
+	 *
+	 * Walking [sw_head, sw_tail) is not enough: refill is batched
+	 * (aq_ring_rx_fill() waits for AQ_CFG_RX_REFILL_THRES free slots),
+	 * so slots that were cleaned but not yet reposted accumulate in the
+	 * [sw_tail, sw_head) gap, and they keep their page for reuse. Walk
+	 * the whole ring and release whatever is left.
+	 */
+	for (i = 0; i < self->size; i++) {
+		struct aq_ring_buff_s *buff = &self->buff_ring[i];
+
+		if (!buff->rxdata.page)
+			continue;
 
 		aq_free_rxpage(&buff->rxdata, aq_nic_get_dev(self->aq_nic));
 	}
+
+	self->sw_head = self->sw_tail;
 }
 
 void aq_ring_free(struct aq_ring_s *self)

drivers/net/ethernet/aquantia/atlantic/aq_ring.h

@@ -202,6 +202,7 @@ void aq_ring_update_queue_state(struct aq_ring_s *ring);
 void aq_ring_queue_wake(struct aq_ring_s *ring);
 void aq_ring_queue_stop(struct aq_ring_s *ring);
 bool aq_ring_tx_clean(struct aq_ring_s *self);
+void aq_ring_tx_deinit(struct aq_ring_s *self);
 int aq_xdp_xmit(struct net_device *dev, int num_frames,
 		struct xdp_frame **frames, u32 flags);
 int aq_ring_rx_clean(struct aq_ring_s *self,

drivers/net/ethernet/aquantia/atlantic/aq_vec.c

@@ -275,7 +275,7 @@ void aq_vec_deinit(struct aq_vec_s *self)
 
 	for (i = 0U; self->tx_rings > i; ++i) {
 		ring = self->ring[i];
-		aq_ring_tx_clean(&ring[AQ_VEC_TX_ID]);
+		aq_ring_tx_deinit(&ring[AQ_VEC_TX_ID]);
 		aq_ring_rx_deinit(&ring[AQ_VEC_RX_ID]);
 	}