[PATCH v2 net-next] net: fec: implement TSO descriptor cleanup

[Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>]

Implement cleanup of descriptors in the TSO error path of
fec_enet_txq_submit_tso(). The cleanup

- Unmaps DMA buffers for data descriptors skipping TSO header
- Clears all buffer descriptors
- Handles extended descriptors by clearing cbd_esc when enabled

Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
---
Changelog:

v2
	- Add DMA unmapping for data descriptors
	- Handle extended descriptor (bufdesc_ex) cleanup
	- Move variable declarations to function scope

 drivers/net/ethernet/freescale/fec_main.c | 29 ++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 68725506a095..acd381710f87 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -840,6 +840,8 @@ static int fec_enet_txq_submit_tso(struct fec_enet_priv_tx_q *txq,
 	struct fec_enet_private *fep = netdev_priv(ndev);
 	int hdr_len, total_len, data_left;
 	struct bufdesc *bdp = txq->bd.cur;
+	struct bufdesc *tmp_bdp;
+	struct bufdesc_ex *ebdp;
 	struct tso_t tso;
 	unsigned int index = 0;
 	int ret;
@@ -913,7 +915,32 @@ static int fec_enet_txq_submit_tso(struct fec_enet_priv_tx_q *txq,
 	return 0;
 
 err_release:
-	/* TODO: Release all used data descriptors for TSO */
+	/* Release all used data descriptors for TSO */
+	tmp_bdp = txq->bd.cur;
+
+	while (tmp_bdp != bdp) {
+		/* Unmap data buffers */
+		if (tmp_bdp->cbd_bufaddr && tmp_bdp != txq->bd.cur)
+			dma_unmap_single(&fep->pdev->dev,
+					 tmp_bdp->cbd_bufaddr,
+					 tmp_bdp->cbd_datlen,
+					 DMA_TO_DEVICE);
+
+		/* Clear standard buffer descriptor fields */
+		tmp_bdp->cbd_sc = 0;
+		tmp_bdp->cbd_datlen = 0;
+		tmp_bdp->cbd_bufaddr = 0;
+
+		/* Handle extended descriptor if enabled */
+		if (fep->bufdesc_ex) {
+			ebdp = (struct bufdesc_ex *)tmp_bdp;
+			ebdp->cbd_esc = 0;
+		}
+
+		tmp_bdp = fec_enet_get_nextdesc(tmp_bdp, &txq->bd);
+	}
+
+	dev_kfree_skb_any(skb);
 	return ret;
 }
 
-- 
2.34.1