[PATCH net v4 07/15] net: stmmac: unwind partially allocated DMA configurations

[James Hilliard <james.hilliard1@gmail.com>]

RX and TX allocation failure paths release all configured queues, even
when the failing queue has not allocated its buffer array or
descriptors. Only walk buffer arrays and free coherent memory when those
allocations exist. If TX allocation fails after RX allocation succeeds,
release the RX resources too.

Propagate RXQ memory-model registration errors instead of continuing
with an unusable RXQ. Clear XSK RXQ bindings before the RXQ goes away,
release any saved partial packet, and clear released resource pointers.
This also leaves configurations which are reused after close or XDP
reconfiguration with a consistent empty state.

The MTU transaction added later relies on preparation failures being
fully unwound without touching the currently active configuration.

Take ownership of saved partial RX state at poll entry by clearing the
saved flag and skb pointer immediately. Preserve incomplete state if the
next descriptor is still DMA-owned. A budget-one completion must not
leave an already delivered or freed skb reachable by the new teardown
cleanup.

Fixes: 71fedb0198cb ("net: stmmac: break some functions into RX and TX scopes")
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 69 +++++++++++++++++------
 1 file changed, 52 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index bdebc5bfa2b8..1cc68c1cf37d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1766,6 +1766,9 @@ static void dma_free_rx_skbufs(struct stmmac_priv *priv,
 	struct stmmac_rx_queue *rx_q = &dma_conf->rx_queue[queue];
 	int i;
 
+	if (!rx_q->buf_pool)
+		return;
+
 	for (i = 0; i < dma_conf->dma_rx_size; i++)
 		stmmac_free_rx_buffer(priv, rx_q, i);
 }
@@ -1889,17 +1892,19 @@ static int __init_dma_rx_desc_rings(struct stmmac_priv *priv,
 	rx_q->xsk_pool = stmmac_get_xsk_pool(priv, queue);
 
 	if (rx_q->xsk_pool) {
-		WARN_ON(xdp_rxq_info_reg_mem_model(&rx_q->xdp_rxq,
-						   MEM_TYPE_XSK_BUFF_POOL,
-						   NULL));
+		ret = xdp_rxq_info_reg_mem_model(&rx_q->xdp_rxq,
+						 MEM_TYPE_XSK_BUFF_POOL, NULL);
+		if (ret)
+			return ret;
 		netdev_info(priv->dev,
 			    "Register MEM_TYPE_XSK_BUFF_POOL RxQ-%d\n",
 			    queue);
 		xsk_pool_set_rxq_info(rx_q->xsk_pool, &rx_q->xdp_rxq);
 	} else {
-		WARN_ON(xdp_rxq_info_reg_mem_model(&rx_q->xdp_rxq,
-						   MEM_TYPE_PAGE_POOL,
-						   rx_q->page_pool));
+		ret = xdp_rxq_info_reg_mem_model(&rx_q->xdp_rxq,
+						 MEM_TYPE_PAGE_POOL, rx_q->page_pool);
+		if (ret)
+			return ret;
 		netdev_info(priv->dev,
 			    "Register MEM_TYPE_PAGE_POOL RxQ-%d\n",
 			    queue);
@@ -1961,6 +1966,8 @@ static int init_dma_rx_desc_rings(struct net_device *dev,
 			dma_free_rx_skbufs(priv, dma_conf, queue);
 
 		rx_q->buf_alloc_num = 0;
+		if (rx_q->xsk_pool)
+			xsk_pool_set_rxq_info(rx_q->xsk_pool, NULL);
 		rx_q->xsk_pool = NULL;
 
 		queue--;
@@ -2104,6 +2111,9 @@ static void dma_free_tx_skbufs(struct stmmac_priv *priv,
 
 	tx_q->xsk_frames_done = 0;
 
+	if (!tx_q->tx_skbuff_dma || !tx_q->tx_skbuff)
+		return;
+
 	for (i = 0; i < dma_conf->dma_tx_size; i++)
 		stmmac_free_tx_buffer(priv, dma_conf, queue, i);
 
@@ -2142,10 +2152,16 @@ static void __free_dma_rx_desc_resources(struct stmmac_priv *priv,
 	void *addr;
 
 	/* Release the DMA RX socket buffers */
-	if (rx_q->xsk_pool)
+	if (rx_q->xsk_pool) {
 		dma_free_rx_xskbufs(priv, dma_conf, queue);
-	else
+		xsk_pool_set_rxq_info(rx_q->xsk_pool, NULL);
+	} else {
 		dma_free_rx_skbufs(priv, dma_conf, queue);
+	}
+	if (rx_q->state_saved)
+		dev_kfree_skb_any(rx_q->state.skb);
+	rx_q->state.skb = NULL;
+	rx_q->state_saved = 0;
 
 	rx_q->buf_alloc_num = 0;
 	rx_q->xsk_pool = NULL;
@@ -2158,7 +2174,8 @@ static void __free_dma_rx_desc_resources(struct stmmac_priv *priv,
 
 	size = stmmac_get_rx_desc_size(priv) * dma_conf->dma_rx_size;
 
-	dma_free_coherent(priv->device, size, addr, rx_q->dma_rx_phy);
+	if (addr)
+		dma_free_coherent(priv->device, size, addr, rx_q->dma_rx_phy);
 
 	if (xdp_rxq_info_is_reg(&rx_q->xdp_rxq))
 		xdp_rxq_info_unreg(&rx_q->xdp_rxq);
@@ -2166,6 +2183,10 @@ static void __free_dma_rx_desc_resources(struct stmmac_priv *priv,
 	kfree(rx_q->buf_pool);
 	if (rx_q->page_pool)
 		page_pool_destroy(rx_q->page_pool);
+	rx_q->buf_pool = NULL;
+	rx_q->page_pool = NULL;
+	rx_q->dma_erx = NULL;
+	rx_q->dma_rx = NULL;
 }
 
 static void free_dma_rx_desc_resources(struct stmmac_priv *priv,
@@ -2206,10 +2227,16 @@ static void __free_dma_tx_desc_resources(struct stmmac_priv *priv,
 
 	size = stmmac_get_tx_desc_size(priv, tx_q) * dma_conf->dma_tx_size;
 
-	dma_free_coherent(priv->device, size, addr, tx_q->dma_tx_phy);
+	if (addr)
+		dma_free_coherent(priv->device, size, addr, tx_q->dma_tx_phy);
 
 	kfree(tx_q->tx_skbuff_dma);
 	kfree(tx_q->tx_skbuff);
+	tx_q->tx_skbuff_dma = NULL;
+	tx_q->tx_skbuff = NULL;
+	tx_q->dma_etx = NULL;
+	tx_q->dma_entx = NULL;
+	tx_q->dma_tx = NULL;
 }
 
 static void free_dma_tx_desc_resources(struct stmmac_priv *priv,
@@ -2416,6 +2443,8 @@ static int alloc_dma_desc_resources(struct stmmac_priv *priv,
 		return ret;
 
 	ret = alloc_dma_tx_desc_resources(priv, dma_conf);
+	if (ret)
+		free_dma_rx_desc_resources(priv, dma_conf);
 
 	return ret;
 }
@@ -5726,6 +5755,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 	struct sk_buff *skb = NULL;
 	struct stmmac_xdp_buff ctx;
 	int xdp_status = 0;
+	bool in_progress = rx_q->state_saved;
 	int bufsz;
 
 	dma_dir = page_pool_get_dma_dir(rx_q->page_pool);
@@ -5740,6 +5770,14 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 		stmmac_display_ring(priv, rx_head, priv->dma_conf.dma_rx_size, true,
 				    rx_q->dma_rx_phy, desc_size);
 	}
+	if (in_progress) {
+		skb = rx_q->state.skb;
+		error = rx_q->state.error;
+		len = rx_q->state.len;
+		rx_q->state.skb = NULL;
+		rx_q->state_saved = false;
+	}
+
 	while (count < limit) {
 		unsigned int buf1_len = 0, buf2_len = 0;
 		enum pkt_hash_types hash_type;
@@ -5748,12 +5786,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 		int entry;
 		u32 hash;
 
-		if (!count && rx_q->state_saved) {
-			skb = rx_q->state.skb;
-			error = rx_q->state.error;
-			len = rx_q->state.len;
-		} else {
-			rx_q->state_saved = false;
+		if (!in_progress) {
 			skb = NULL;
 			error = 0;
 			len = 0;
@@ -5787,6 +5820,8 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 
 		prefetch(np);
 
+		in_progress = status & rx_not_ls;
+
 		if (priv->extend_desc)
 			stmmac_rx_extended_status(priv, &priv->xstats, rx_q->dma_erx + entry);
 		if (unlikely(status == discard_frame)) {
@@ -5961,7 +5996,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
 		count++;
 	}
 
-	if (status & rx_not_ls || skb) {
+	if (in_progress || skb) {
 		rx_q->state_saved = true;
 		rx_q->state.skb = skb;
 		rx_q->state.error = error;

-- 
2.53.0