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

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

[Dheeraj Reddy Jonnalagadda]

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

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

[Wei Fang]

> 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)

All the TSO headers will be unmapped except the first one. So please
use the following check condition.

if (!IS_TSO_HEADER(txq, fec32_to_cpu(tmp_bdp->cbd_bufaddr)))

BTW, the net-next is closed until Feb 3rd. And I think this is a
bug fix not a new feature, so you can change the target to net
tree and a Fixes tag, thanks.

> +			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