net: ftgmac100: fix ring allocation unwind on open failure

commit c0fd0fe745f5e8c568d898cd1513d0083e46204a upstream.

ftgmac100_alloc_rings() allocates rx_skbs, tx_skbs, rxdes, txdes, and
rx_scratch in stages. On intermediate failures it returned -ENOMEM
directly, leaking resources allocated earlier in the function.

Rework the failure path to use staged local unwind labels and free
allocated resources in reverse order before returning -ENOMEM. This
matches common netdev allocation cleanup style.

Fixes: d72e01a0430f ("ftgmac100: Use a scratch buffer for failed RX allocations")
Cc: stable@vger.kernel.org
Signed-off-by: Yufan Chen <yufan.chen@linux.dev>
Link: https://patch.msgid.link/20260328163257.60836-1-yufan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 9179014e90d11660bcca2fd8bb17ed06b8254e9a..ac1cc466cec368d1fc610d9f02e1f818adae0386 100644 (file)
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -931,19 +931,19 @@ static int ftgmac100_alloc_rings(struct ftgmac100 *priv)
        priv->tx_skbs = kcalloc(MAX_TX_QUEUE_ENTRIES, sizeof(void *),
                                GFP_KERNEL);
        if (!priv->tx_skbs)
-               return -ENOMEM;
+               goto err_free_rx_skbs;
 
        /* Allocate descriptors */
        priv->rxdes = dma_alloc_coherent(priv->dev,
                                         MAX_RX_QUEUE_ENTRIES * sizeof(struct ftgmac100_rxdes),
                                         &priv->rxdes_dma, GFP_KERNEL);
        if (!priv->rxdes)
-               return -ENOMEM;
+               goto err_free_tx_skbs;
        priv->txdes = dma_alloc_coherent(priv->dev,
                                         MAX_TX_QUEUE_ENTRIES * sizeof(struct ftgmac100_txdes),
                                         &priv->txdes_dma, GFP_KERNEL);
        if (!priv->txdes)
-               return -ENOMEM;
+               goto err_free_rxdes;
 
        /* Allocate scratch packet buffer */
        priv->rx_scratch = dma_alloc_coherent(priv->dev,
@@ -951,9 +951,29 @@ static int ftgmac100_alloc_rings(struct ftgmac100 *priv)
                                              &priv->rx_scratch_dma,
                                              GFP_KERNEL);
        if (!priv->rx_scratch)
-               return -ENOMEM;
+               goto err_free_txdes;
 
        return 0;
+
+err_free_txdes:
+       dma_free_coherent(priv->dev,
+                         MAX_TX_QUEUE_ENTRIES *
+                         sizeof(struct ftgmac100_txdes),
+                         priv->txdes, priv->txdes_dma);
+       priv->txdes = NULL;
+err_free_rxdes:
+       dma_free_coherent(priv->dev,
+                         MAX_RX_QUEUE_ENTRIES *
+                         sizeof(struct ftgmac100_rxdes),
+                         priv->rxdes, priv->rxdes_dma);
+       priv->rxdes = NULL;
+err_free_tx_skbs:
+       kfree(priv->tx_skbs);
+       priv->tx_skbs = NULL;
+err_free_rx_skbs:
+       kfree(priv->rx_skbs);
+       priv->rx_skbs = NULL;
+       return -ENOMEM;
 }
 
 static void ftgmac100_init_rings(struct ftgmac100 *priv)