On Fri, Jan 06, 2017 at 10:02:36PM +0300, Sergei Shtylyov wrote:
> Hello!
>
> On 01/05/2017 01:43 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>
> >--
> >v1 [Kazuya Mizuguchi]
> >
> >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
>
> Not sure that was good idea (sorry)... ravb_tx_ring() only unmaps the
> transmitted buffers, while we need to unmap everything...
>
> >* Reduce scope of new local variable
> >---
> > drivers/net/ethernet/renesas/ravb_main.c | 89
> > ++++++++++++++++++--------------
> > 1 file changed, 51 insertions(+), 38 deletions(-)
> >
> >diff --git a/drivers/net/ethernet/renesas/ravb_main.c
> >b/drivers/net/ethernet/renesas/ravb_main.c
> >index 92d7692c840d..1797c48e3176 100644
> >--- a/drivers/net/ethernet/renesas/ravb_main.c
> >+++ b/drivers/net/ethernet/renesas/ravb_main.c
> >@@ -179,6 +179,44 @@ static struct mdiobb_ops bb_ops = {
> > .get_mdio_data = ravb_get_mdio_data,
> > };
> >
> >+/* Free TX skb function for AVB-IP */
> >+static int ravb_tx_free(struct net_device *ndev, int q)
> >+{
> >+ 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 (desc->die_dt != DT_FEMPTY)
>
> Here, it stop once an untransmitted buffer is encountered...
Yes, I see that now.
I wonder if we should:
a) paramatise ravb_tx_free() so it may either clear all transmitted buffers
(current behaviour) or all buffers (new behaviour).
b) provide a different version of this loop in ravb_ring_free()
What are your thoughts?
> >+ 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;
> >+ desc->die_dt = DT_EEMPTY;
> >+ }
> >+ return free_num;
> >+}
> >+
> > /* Free skb's and DMA buffers for Ethernet AVB */
> > static void ravb_ring_free(struct net_device *ndev, int q)
> > {
> >@@ -207,6 +245,18 @@ static void ravb_ring_free(struct net_device *ndev, int
> >q)
> > priv->tx_align[q] = NULL;
> >
> > if (priv->rx_ring[q]) {
> >+ for (i = 0; i < priv->num_rx_ring[q]; i++) {
> >+ struct ravb_ex_rx_desc *rx_desc = &priv->rx_ring[q][i];
> >+
> >+ if (!dma_mapping_error(ndev->dev.parent,
> >+ rx_desc->dptr)) {
>
> You forgot le32_to_cpu() here, we can't use the raw descriptor fields.
Thanks, I will fix that.
> >+ dma_unmap_single(ndev->dev.parent,
> >+ le32_to_cpu(rx_desc->dptr),
> >+ PKT_BUF_SZ,
> >+ DMA_FROM_DEVICE);
> >+ rx_desc->ds_cc = cpu_to_le16(0);
>
> You don't check it anyway, not sure what that buys...
Thanks, I will see about dropping that.
