[PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-05 Thread Simon Horman 
From: Kazuya Mizuguchi 

"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 
[simon: reworked]
Signed-off-by: Simon Horman 
--
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
* 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)
+   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)) {
+   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);
+   }
+   }
ring_size = sizeof(struct ravb_ex_rx_desc) *
(priv->num_rx_ring[q] + 1);
dma_free_coherent(ndev->dev.parent, ring_size, priv->rx_ring[q],
@@ -215,6 +265,7 @@ static void ravb_ring_free(struct net_device *ndev, int q)
}
 
if (priv->tx_ring[q]) {
+   ravb_tx_free(ndev, q);
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],
@@ -431,44 +482,6 @@ static int ravb_dmac_init(struct net_device *ndev)
return 0;
 }
 
-/* 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);
-

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-06 Thread Sergei Shtylyov 

Hello!

On 01/05/2017 01:43 PM, Simon Horman wrote:


From: Kazuya Mizuguchi 

"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 
[simon: reworked]
Signed-off-by: Simon Horman 
--
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...


+   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.


+   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...

[...]

MBR, Sergei

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-12 Thread Simon Horman 
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 
> >
> >"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 
> >[simon: reworked]
> >Signed-off-by: Simon Horman 
> >--
> >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.

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-12 Thread Sergei Shtylyov 

On 01/12/2017 12:11 PM, Simon Horman wrote:


From: Kazuya Mizuguchi 

"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 
[simon: reworked]
Signed-off-by: Simon Horman 
--
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?


   I'm voting for (b).

[...]

MBR, Sergei

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-12 Thread Simon Horman 
On Thu, Jan 12, 2017 at 03:03:05PM +0300, Sergei Shtylyov wrote:
> On 01/12/2017 12:11 PM, Simon Horman wrote:

...

> >>   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?
> 
>I'm voting for (b).

Ok, something like this?

@@ -215,6 +225,30 @@ static void ravb_ring_free(struct net_device *ndev, int q)
}
 
if (priv->tx_ring[q]) {
+   for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; 
priv->dirty_tx[q]++) {
+   struct ravb_tx_desc *desc;
+   int entry;
+
+   entry = priv->dirty_tx[q] % (priv->num_tx_ring[q] *
+NUM_TX_DESC);
+   desc = &priv->tx_ring[q][entry];
+
+   /* Free the original skb. */
+   if (priv->tx_skb[q][entry / NUM_TX_DESC]) {
+   u32 size = le16_to_cpu(desc->ds_tagl) & TX_DS;
+
+   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;
+   }
+   }
+   }
+
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],

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-12 Thread Lino Sanfilippo 

Hi,

On 12.01.2017 10:11, Simon Horman wrote:


+
+   for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; priv->dirty_tx[q]++) {


BTW: How can this work correctly when cur_tx wraps and dirty_tx is greater?

Regards,
Lino

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-12 Thread Sergei Shtylyov 

On 01/12/2017 04:18 PM, Simon Horman wrote:


...


  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?


   I'm voting for (b).


Ok, something like this?

@@ -215,6 +225,30 @@ static void ravb_ring_free(struct net_device *ndev, int q)
}

if (priv->tx_ring[q]) {
+   for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; 
priv->dirty_tx[q]++) {


   You're still copying the loop logic from ravb_tx_free() while we (I think) 
need a simple loop over all the descriptor ring.


[...]

MBR, Sergei

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-12 Thread Sergei Shtylyov 

On 01/12/2017 04:23 PM, Lino Sanfilippo wrote:


+
+for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; priv->dirty_tx[q]++) {


BTW: How can this work correctly when cur_tx wraps and dirty_tx is greater?


   {cur|dirty}_tx never wrap.


Regards,
Lino


MBR, Sergei

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-13 Thread Simon Horman 
On Thu, Jan 12, 2017 at 07:33:51PM +0300, Sergei Shtylyov wrote:
> On 01/12/2017 04:18 PM, Simon Horman wrote:
> 
> >...
> >
>   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?
> >>
> >>   I'm voting for (b).
> >
> >Ok, something like this?
> >
> >@@ -215,6 +225,30 @@ static void ravb_ring_free(struct net_device *ndev, int 
> >q)
> > }
> >
> > if (priv->tx_ring[q]) {
> >+for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; 
> >priv->dirty_tx[q]++) {
> 
>You're still copying the loop logic from ravb_tx_free() while we (I
> think) need a simple loop over all the descriptor ring.

I thought the above may be better as it seems to me that only descriptors
in the range described above could need to be freed. But simpler may be
better. And I also noticed several other problems with the code I posted
yesterday afternoon.

How about something like this?

@@ -215,6 +225,17 @@ static void ravb_ring_free(struct net_device *ndev, int q)
}
 
if (priv->tx_ring[q]) {
+   for (i = 0; i < priv->num_tx_ring[q] * NUM_TX_DESC; i++) {
+   struct ravb_tx_desc *desc = &priv->tx_ring[q][i];
+
+   if (desc->die_dt != DT_EEMPTY) {
+   u32 size = le16_to_cpu(desc->ds_tagl) & TX_DS;
+
+   dma_unmap_single(ndev->dev.parent,
+le32_to_cpu(desc->dptr),
+size, DMA_TO_DEVICE);
+   }
+   }
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],

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-16 Thread Sergei Shtylyov 

Hello!

On 01/12/2017 04:18 PM, Simon Horman wrote:


...



  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?


   I'm voting for (b).


   After looking at this issue for another time, I'll vote for (a). Sorry for 
back-and-forth on this matter -- I somehow thought we could do a better job by 
scanning all the TX ring...



Ok, something like this?

@@ -215,6 +225,30 @@ static void ravb_ring_free(struct net_device *ndev, int q)
}

if (priv->tx_ring[q]) {
+   for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; 
priv->dirty_tx[q]++) {
+   struct ravb_tx_desc *desc;
+   int entry;
+
+   entry = priv->dirty_tx[q] % (priv->num_tx_ring[q] *
+NUM_TX_DESC);
+   desc = &priv->tx_ring[q][entry];
+
+   /* Free the original skb. */
+   if (priv->tx_skb[q][entry / NUM_TX_DESC]) {
+   u32 size = le16_to_cpu(desc->ds_tagl) & TX_DS;
+
+   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;
+   }
+   }
+   }
+


   This is only different from ravb_tx_free() by not stopping on unfinished 
descriptor, so we must be good with adding an extra param to it...


[...]

MBR, Sergei

Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-23 Thread Simon Horman 
On Mon, Jan 16, 2017 at 11:41:51PM +0300, Sergei Shtylyov wrote:
> Hello!
> 
> On 01/12/2017 04:18 PM, Simon Horman wrote:
> 
> >...
> 
>   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?
> >>
> >>   I'm voting for (b).
> 
>After looking at this issue for another time, I'll vote for (a). Sorry
> for back-and-forth on this matter -- I somehow thought we could do a better
> job by scanning all the TX ring...

No problem. I also have had several opinions on this over time.
I'll see about respinning the patch.

> 
> >Ok, something like this?
> >
> >@@ -215,6 +225,30 @@ static void ravb_ring_free(struct net_device *ndev, int 
> >q)
> > }
> >
> > if (priv->tx_ring[q]) {
> >+for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; 
> >priv->dirty_tx[q]++) {
> >+struct ravb_tx_desc *desc;
> >+int entry;
> >+
> >+entry = priv->dirty_tx[q] % (priv->num_tx_ring[q] *
> >+ NUM_TX_DESC);
> >+desc = &priv->tx_ring[q][entry];
> >+
> >+/* Free the original skb. */
> >+if (priv->tx_skb[q][entry / NUM_TX_DESC]) {
> >+u32 size = le16_to_cpu(desc->ds_tagl) & TX_DS;
> >+
> >+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;
> >+}
> >+}
> >+}
> >+
> 
>This is only different from ravb_tx_free() by not stopping on unfinished
> descriptor, so we must be good with adding an extra param to it...
> 
> [...]
> 
> MBR, Sergei
>

Re: [EXT] Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-12 Thread Lino Sanfilippo 

Hi,

On 12.01.2017 17:37, Sergei Shtylyov wrote:

External Email

--
On 01/12/2017 04:23 PM, Lino Sanfilippo wrote:


+
+for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; priv->dirty_tx[q]++) {


BTW: How can this work correctly when cur_tx wraps and dirty_tx is greater?


   {cur|dirty}_tx never wrap.



Both values are 32 bit and AFAICS they are only incremented (and never reset or
decremented).
So what prevents them from wrapping every 2^32 processed tx descriptors? Am I 
missing
something?

Regards,
Lino

Re: [EXT] Re: [PATCH/RFC v2 net-next] ravb: unmap descriptors when freeing rings

2017-01-12 Thread Sergei Shtylyov 

On 01/12/2017 07:55 PM, Lino Sanfilippo wrote:


+
+for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; priv->dirty_tx[q]++) {


BTW: How can this work correctly when cur_tx wraps and dirty_tx is greater?


   {cur|dirty}_tx never wrap.



Both values are 32 bit and AFAICS they are only incremented (and never reset or
decremented).


   Yeah, sorry, O thought you mean the TX ring size wrapping.


So what prevents them from wrapping every 2^32 processed tx descriptors? Am I
missing
something?


   The math should still work all right IIUC.


Regards,
Lino


MBR, Sergei