Re: [PATCH/RFC v3 net] ravb: unmap descriptors when freeing rings
From: Sergei Shtylyov <hidden>
Date: 2017-01-25 16:05:13
Also in:
linux-renesas-soc
Hello. On 01/24/2017 09:21 PM, Simon Horman wrote:
quoted hunk ↗ jump to hunk
From: Kazuya Mizuguchi <redacted> "swiotlb buffer is full" errors occur after repeated initialisation of a device - f.e. suspend/resume or ip link set up/down. This is because memory mapped using dma_map_single() in ravb_ring_format() and ravb_start_xmit() is not released. Resolve this problem by unmapping descriptors when freeing rings. Note, ravb_tx_free() is moved but not otherwise modified by this patch. Signed-off-by: Kazuya Mizuguchi <redacted> [simon: reworked] Signed-off-by: Simon Horman <redacted> -- v3 [Simon Horman] * As suggested by Sergei Shtylyov - consistently use le32_to_cpu(desc->dptr) - Do not clear desc->ds_cc as it is not used * Paramatise ravb_tx_free() to allow it to free non-transmitted buffers v2 [Simon Horman] * As suggested by Sergei Shtylyov - Use dma_mapping_error() and rx_desc->ds_cc when unmapping RX descriptors; this is consistent with the way that they are mapped - Use ravb_tx_free() to clear TX descriptors * Reduce scope of new local variable v1 [Kazuya Mizuguchi] --- drivers/net/ethernet/renesas/ravb_main.c | 113 ++++++++++++++++++------------- 1 file changed, 65 insertions(+), 48 deletions(-)diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index 89ac1e3f6175..57fe1411bb9d 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c@@ -179,6 +179,51 @@ static struct mdiobb_ops bb_ops = { .get_mdio_data = ravb_get_mdio_data, }; +enum ravb_tx_free_mode { + ravb_tx_free_all, + ravb_tx_free_txed_only, +}; + +/* Free TX skb function for AVB-IP */ +static int ravb_tx_free(struct net_device *ndev, int q, + enum ravb_tx_free_mode free_mode)
Hmm... Sorry but this looks over-engineered. A *bool* parameter (named e.g
'all) would suffice IMHO.
+{
+ struct ravb_private *priv = netdev_priv(ndev);
+ struct net_device_stats *stats = &priv->stats[q];
+ struct ravb_tx_desc *desc;
+ int free_num = 0;
+ int entry;
+ u32 size;
+
+ for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; priv->dirty_tx[q]++) {
+ entry = priv->dirty_tx[q] % (priv->num_tx_ring[q] *
+ NUM_TX_DESC);
+ desc = &priv->tx_ring[q][entry];
+ if (free_mode == ravb_tx_free_txed_only &&
+ desc->die_dt != DT_FEMPTY)
+ break;
+ /* Descriptor type must be checked before all other reads */
+ dma_rmb();
+ size = le16_to_cpu(desc->ds_tagl) & TX_DS;
+ /* Free the original skb. */
+ if (priv->tx_skb[q][entry / NUM_TX_DESC]) {
+ dma_unmap_single(ndev->dev.parent, le32_to_cpu(desc->dptr),
+ size, DMA_TO_DEVICE);
+ /* Last packet descriptor? */
+ if (entry % NUM_TX_DESC == NUM_TX_DESC - 1) {
+ entry /= NUM_TX_DESC;
+ dev_kfree_skb_any(priv->tx_skb[q][entry]);
+ priv->tx_skb[q][entry] = NULL;
+ stats->tx_packets++;
+ }
+ free_num++;
+ }
+ stats->tx_bytes += size;
Hmmm... we shouldn't count the discarded unsent packets/bytes as sent, right?
[...]quoted hunk ↗ jump to hunk
@@ -215,12 +262,19 @@ static void ravb_ring_free(struct net_device *ndev, int q) } if (priv->tx_ring[q]) { + ravb_tx_free(ndev, q, ravb_tx_free_all); + ring_size = sizeof(struct ravb_tx_desc) * (priv->num_tx_ring[q] * NUM_TX_DESC + 1); dma_free_coherent(ndev->dev.parent, ring_size, priv->tx_ring[q], priv->tx_desc_dma[q]); priv->tx_ring[q] = NULL; } + + /* Free TX skb ringbuffer. + * SKBs are freed by ravb_tx_free() call above. */
This is not a recommended comment format:
/* bla
* bla
*/
[...]
MBR, Sergei