On Wed, Jan 25, 2017 at 07:05:08PM +0300, Sergei Shtylyov wrote:
> Hello.
>
> On 01/24/2017 09:21 PM, Simon Horman wrote:
>
> >From: Kazuya Mizuguchi <kazuya.mizuguchi...@renesas.com>
> >
> >"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 <kazuya.mizuguchi...@renesas.com>
> >[simon: reworked]
> >Signed-off-by: Simon Horman <horms+rene...@verge.net.au>
> >--
> >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.
Ha! The last time I used a bool for something like this I was encouraged
to use an enum, admittedly that was not kernel code but I was unsure
which way to go this time. I'll change things to bool as you sugget.
> >+{
> >+ 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?
Yes, I think so. Sorry for missing that.
> [...]
> >@@ -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
> */
Thanks, I will fix that.
