2017-04-10 18:33:51

by Niklas Cassel

[permalink] [raw]
Subject: [PATCH net-next] net: stmmac: set total length of the packet to be transmitted in TDES3

From: Niklas Cassel <[email protected]>

Field FL/TPL in register TDES3 is not correctly set on GMAC4.
TX appears to be functional on GMAC 4.10a even if this field is not set,
however, to avoid relying on undefined behavior, set the length in TDES3.

The field has a different meaning depending on if the TSE bit in TDES3
is set or not (TSO). However, regardless of the TSE bit, the field is
not optional. The field is already set correctly when the TSE bit is set.

Since there is no limit for the number of descriptors that can be
used for a single packet, the field should be set to the sum of
the buffers contained in:
[<desc with First Descriptor bit set> ... <desc n> ...
<desc with Last Descriptor bit set>], which should be equal to skb->len.

Signed-off-by: Niklas Cassel <[email protected]>
---
drivers/net/ethernet/stmicro/stmmac/chain_mode.c | 6 +++---
drivers/net/ethernet/stmicro/stmmac/common.h | 2 +-
drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c | 3 ++-
drivers/net/ethernet/stmicro/stmmac/enh_desc.c | 2 +-
drivers/net/ethernet/stmicro/stmmac/norm_desc.c | 2 +-
drivers/net/ethernet/stmicro/stmmac/ring_mode.c | 9 ++++++---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++--
7 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
index 37881f81319e..e93c40b4631e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
@@ -52,7 +52,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
tx_q->tx_skbuff_dma[entry].len = bmax;
/* do not close the descriptor and do not set own bit */
priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
- 0, false);
+ 0, false, skb->len);

while (len != 0) {
tx_q->tx_skbuff[entry] = NULL;
@@ -70,7 +70,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
tx_q->tx_skbuff_dma[entry].len = bmax;
priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
STMMAC_CHAIN_MODE, 1,
- false);
+ false, skb->len);
len -= bmax;
i++;
} else {
@@ -85,7 +85,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
/* last descriptor can be set now */
priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
STMMAC_CHAIN_MODE, 1,
- true);
+ true, skb->len);
len = 0;
}
}
diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index 90d28bcad880..b7ce3fbb5375 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -373,7 +373,7 @@ struct stmmac_desc_ops {
/* Invoked by the xmit function to prepare the tx descriptor */
void (*prepare_tx_desc) (struct dma_desc *p, int is_fs, int len,
bool csum_flag, int mode, bool tx_own,
- bool ls);
+ bool ls, unsigned int tot_pkt_len);
void (*prepare_tso_tx_desc)(struct dma_desc *p, int is_fs, int len1,
int len2, bool tx_own, bool ls,
unsigned int tcphdrlen,
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
index 843ec69222ea..aa6476439aee 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
@@ -304,12 +304,13 @@ static void dwmac4_rd_init_tx_desc(struct dma_desc *p, int mode, int end)

static void dwmac4_rd_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
bool csum_flag, int mode, bool tx_own,
- bool ls)
+ bool ls, unsigned int tot_pkt_len)
{
unsigned int tdes3 = le32_to_cpu(p->des3);

p->des2 |= cpu_to_le32(len & TDES2_BUFFER1_SIZE_MASK);

+ tdes3 |= tot_pkt_len & TDES3_PACKET_SIZE_MASK;
if (is_fs)
tdes3 |= TDES3_FIRST_DESCRIPTOR;
else
diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
index 323b59ec74a3..7546b3664113 100644
--- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
@@ -315,7 +315,7 @@ static void enh_desc_release_tx_desc(struct dma_desc *p, int mode)

static void enh_desc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
bool csum_flag, int mode, bool tx_own,
- bool ls)
+ bool ls, unsigned int tot_pkt_len)
{
unsigned int tdes0 = le32_to_cpu(p->des0);

diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
index efb818ebd55e..f817f8f36569 100644
--- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
@@ -191,7 +191,7 @@ static void ndesc_release_tx_desc(struct dma_desc *p, int mode)

static void ndesc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
bool csum_flag, int mode, bool tx_own,
- bool ls)
+ bool ls, unsigned int tot_pkt_len)
{
unsigned int tdes1 = le32_to_cpu(p->des1);

diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
index 31213e64513d..28e4b5d50ce6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
@@ -59,7 +59,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)

desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
- STMMAC_RING_MODE, 0, false);
+ STMMAC_RING_MODE, 0,
+ false, skb->len);
tx_q->tx_skbuff[entry] = NULL;
entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);

@@ -79,7 +80,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)

desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
- STMMAC_RING_MODE, 1, true);
+ STMMAC_RING_MODE, 1,
+ true, skb->len);
} else {
des2 = dma_map_single(priv->device, skb->data,
nopaged_len, DMA_TO_DEVICE);
@@ -91,7 +93,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
tx_q->tx_skbuff_dma[entry].is_jumbo = true;
desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
- STMMAC_RING_MODE, 0, true);
+ STMMAC_RING_MODE, 0,
+ true, skb->len);
}

tx_q->cur_tx = entry;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index a89f76b27ea2..5c1ebc70bebd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3033,7 +3033,8 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)

/* Prepare the descriptor and set the own bit too */
priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion,
- priv->mode, 1, last_segment);
+ priv->mode, 1, last_segment,
+ skb->len);
}

entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
@@ -3116,7 +3117,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
/* Prepare the first descriptor setting the OWN bit too */
priv->hw->desc->prepare_tx_desc(first, 1, nopaged_len,
csum_insertion, priv->mode, 1,
- last_segment);
+ last_segment, skb->len);

/* The own bit must be the latest setting done when prepare the
* descriptor and then barrier is needed to make sure that
--
2.11.0


2017-04-11 05:40:37

by Peppe CAVALLARO

[permalink] [raw]
Subject: Re: [PATCH net-next] net: stmmac: set total length of the packet to be transmitted in TDES3

Hi Niklas

patch looks ok for me, Alex any feedback?

peppe

On 4/10/2017 8:33 PM, Niklas Cassel wrote:
> From: Niklas Cassel <[email protected]>
>
> Field FL/TPL in register TDES3 is not correctly set on GMAC4.
> TX appears to be functional on GMAC 4.10a even if this field is not set,
> however, to avoid relying on undefined behavior, set the length in TDES3.
>
> The field has a different meaning depending on if the TSE bit in TDES3
> is set or not (TSO). However, regardless of the TSE bit, the field is
> not optional. The field is already set correctly when the TSE bit is set.
>
> Since there is no limit for the number of descriptors that can be
> used for a single packet, the field should be set to the sum of
> the buffers contained in:
> [<desc with First Descriptor bit set> ... <desc n> ...
> <desc with Last Descriptor bit set>], which should be equal to skb->len.
>
> Signed-off-by: Niklas Cassel <[email protected]>
> ---
> drivers/net/ethernet/stmicro/stmmac/chain_mode.c | 6 +++---
> drivers/net/ethernet/stmicro/stmmac/common.h | 2 +-
> drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c | 3 ++-
> drivers/net/ethernet/stmicro/stmmac/enh_desc.c | 2 +-
> drivers/net/ethernet/stmicro/stmmac/norm_desc.c | 2 +-
> drivers/net/ethernet/stmicro/stmmac/ring_mode.c | 9 ++++++---
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++--
> 7 files changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
> index 37881f81319e..e93c40b4631e 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
> @@ -52,7 +52,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
> tx_q->tx_skbuff_dma[entry].len = bmax;
> /* do not close the descriptor and do not set own bit */
> priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
> - 0, false);
> + 0, false, skb->len);
>
> while (len != 0) {
> tx_q->tx_skbuff[entry] = NULL;
> @@ -70,7 +70,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
> tx_q->tx_skbuff_dma[entry].len = bmax;
> priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
> STMMAC_CHAIN_MODE, 1,
> - false);
> + false, skb->len);
> len -= bmax;
> i++;
> } else {
> @@ -85,7 +85,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
> /* last descriptor can be set now */
> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
> STMMAC_CHAIN_MODE, 1,
> - true);
> + true, skb->len);
> len = 0;
> }
> }
> diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
> index 90d28bcad880..b7ce3fbb5375 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/common.h
> +++ b/drivers/net/ethernet/stmicro/stmmac/common.h
> @@ -373,7 +373,7 @@ struct stmmac_desc_ops {
> /* Invoked by the xmit function to prepare the tx descriptor */
> void (*prepare_tx_desc) (struct dma_desc *p, int is_fs, int len,
> bool csum_flag, int mode, bool tx_own,
> - bool ls);
> + bool ls, unsigned int tot_pkt_len);
> void (*prepare_tso_tx_desc)(struct dma_desc *p, int is_fs, int len1,
> int len2, bool tx_own, bool ls,
> unsigned int tcphdrlen,
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> index 843ec69222ea..aa6476439aee 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> @@ -304,12 +304,13 @@ static void dwmac4_rd_init_tx_desc(struct dma_desc *p, int mode, int end)
>
> static void dwmac4_rd_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
> bool csum_flag, int mode, bool tx_own,
> - bool ls)
> + bool ls, unsigned int tot_pkt_len)
> {
> unsigned int tdes3 = le32_to_cpu(p->des3);
>
> p->des2 |= cpu_to_le32(len & TDES2_BUFFER1_SIZE_MASK);
>
> + tdes3 |= tot_pkt_len & TDES3_PACKET_SIZE_MASK;
> if (is_fs)
> tdes3 |= TDES3_FIRST_DESCRIPTOR;
> else
> diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
> index 323b59ec74a3..7546b3664113 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
> @@ -315,7 +315,7 @@ static void enh_desc_release_tx_desc(struct dma_desc *p, int mode)
>
> static void enh_desc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
> bool csum_flag, int mode, bool tx_own,
> - bool ls)
> + bool ls, unsigned int tot_pkt_len)
> {
> unsigned int tdes0 = le32_to_cpu(p->des0);
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
> index efb818ebd55e..f817f8f36569 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
> @@ -191,7 +191,7 @@ static void ndesc_release_tx_desc(struct dma_desc *p, int mode)
>
> static void ndesc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
> bool csum_flag, int mode, bool tx_own,
> - bool ls)
> + bool ls, unsigned int tot_pkt_len)
> {
> unsigned int tdes1 = le32_to_cpu(p->des1);
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
> index 31213e64513d..28e4b5d50ce6 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
> @@ -59,7 +59,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
>
> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
> priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
> - STMMAC_RING_MODE, 0, false);
> + STMMAC_RING_MODE, 0,
> + false, skb->len);
> tx_q->tx_skbuff[entry] = NULL;
> entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
>
> @@ -79,7 +80,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
>
> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
> - STMMAC_RING_MODE, 1, true);
> + STMMAC_RING_MODE, 1,
> + true, skb->len);
> } else {
> des2 = dma_map_single(priv->device, skb->data,
> nopaged_len, DMA_TO_DEVICE);
> @@ -91,7 +93,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
> tx_q->tx_skbuff_dma[entry].is_jumbo = true;
> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
> priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
> - STMMAC_RING_MODE, 0, true);
> + STMMAC_RING_MODE, 0,
> + true, skb->len);
> }
>
> tx_q->cur_tx = entry;
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index a89f76b27ea2..5c1ebc70bebd 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -3033,7 +3033,8 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
>
> /* Prepare the descriptor and set the own bit too */
> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion,
> - priv->mode, 1, last_segment);
> + priv->mode, 1, last_segment,
> + skb->len);
> }
>
> entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
> @@ -3116,7 +3117,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
> /* Prepare the first descriptor setting the OWN bit too */
> priv->hw->desc->prepare_tx_desc(first, 1, nopaged_len,
> csum_insertion, priv->mode, 1,
> - last_segment);
> + last_segment, skb->len);
>
> /* The own bit must be the latest setting done when prepare the
> * descriptor and then barrier is needed to make sure that


2017-04-11 07:20:42

by Alexandre Torgue

[permalink] [raw]
Subject: Re: [PATCH net-next] net: stmmac: set total length of the packet to be transmitted in TDES3

Hi,

On 04/11/2017 07:40 AM, Giuseppe CAVALLARO wrote:
> Hi Niklas
>
> patch looks ok for me, Alex any feedback?

It sounds good for me to.
>
> peppe
>
> On 4/10/2017 8:33 PM, Niklas Cassel wrote:
>> From: Niklas Cassel <[email protected]>
>>
>> Field FL/TPL in register TDES3 is not correctly set on GMAC4.
>> TX appears to be functional on GMAC 4.10a even if this field is not set,
>> however, to avoid relying on undefined behavior, set the length in TDES3.
>>
>> The field has a different meaning depending on if the TSE bit in TDES3
>> is set or not (TSO). However, regardless of the TSE bit, the field is
>> not optional. The field is already set correctly when the TSE bit is set.
>>
>> Since there is no limit for the number of descriptors that can be
>> used for a single packet, the field should be set to the sum of
>> the buffers contained in:
>> [<desc with First Descriptor bit set> ... <desc n> ...
>> <desc with Last Descriptor bit set>], which should be equal to skb->len.
>>
>> Signed-off-by: Niklas Cassel <[email protected]>
>> ---
>> drivers/net/ethernet/stmicro/stmmac/chain_mode.c | 6 +++---
>> drivers/net/ethernet/stmicro/stmmac/common.h | 2 +-
>> drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c | 3 ++-
>> drivers/net/ethernet/stmicro/stmmac/enh_desc.c | 2 +-
>> drivers/net/ethernet/stmicro/stmmac/norm_desc.c | 2 +-
>> drivers/net/ethernet/stmicro/stmmac/ring_mode.c | 9 ++++++---
>> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++--
>> 7 files changed, 17 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
>> b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
>> index 37881f81319e..e93c40b4631e 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
>> @@ -52,7 +52,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff
>> *skb, int csum)
>> tx_q->tx_skbuff_dma[entry].len = bmax;
>> /* do not close the descriptor and do not set own bit */
>> priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
>> STMMAC_CHAIN_MODE,
>> - 0, false);
>> + 0, false, skb->len);
>> while (len != 0) {
>> tx_q->tx_skbuff[entry] = NULL;
>> @@ -70,7 +70,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff
>> *skb, int csum)
>> tx_q->tx_skbuff_dma[entry].len = bmax;
>> priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
>> STMMAC_CHAIN_MODE, 1,
>> - false);
>> + false, skb->len);
>> len -= bmax;
>> i++;
>> } else {
>> @@ -85,7 +85,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff
>> *skb, int csum)
>> /* last descriptor can be set now */
>> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
>> STMMAC_CHAIN_MODE, 1,
>> - true);
>> + true, skb->len);
>> len = 0;
>> }
>> }
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h
>> b/drivers/net/ethernet/stmicro/stmmac/common.h
>> index 90d28bcad880..b7ce3fbb5375 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/common.h
>> +++ b/drivers/net/ethernet/stmicro/stmmac/common.h
>> @@ -373,7 +373,7 @@ struct stmmac_desc_ops {
>> /* Invoked by the xmit function to prepare the tx descriptor */
>> void (*prepare_tx_desc) (struct dma_desc *p, int is_fs, int len,
>> bool csum_flag, int mode, bool tx_own,
>> - bool ls);
>> + bool ls, unsigned int tot_pkt_len);
>> void (*prepare_tso_tx_desc)(struct dma_desc *p, int is_fs, int
>> len1,
>> int len2, bool tx_own, bool ls,
>> unsigned int tcphdrlen,
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
>> b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
>> index 843ec69222ea..aa6476439aee 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
>> @@ -304,12 +304,13 @@ static void dwmac4_rd_init_tx_desc(struct
>> dma_desc *p, int mode, int end)
>> static void dwmac4_rd_prepare_tx_desc(struct dma_desc *p, int
>> is_fs, int len,
>> bool csum_flag, int mode, bool tx_own,
>> - bool ls)
>> + bool ls, unsigned int tot_pkt_len)
>> {
>> unsigned int tdes3 = le32_to_cpu(p->des3);
>> p->des2 |= cpu_to_le32(len & TDES2_BUFFER1_SIZE_MASK);
>> + tdes3 |= tot_pkt_len & TDES3_PACKET_SIZE_MASK;
>> if (is_fs)
>> tdes3 |= TDES3_FIRST_DESCRIPTOR;
>> else
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
>> b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
>> index 323b59ec74a3..7546b3664113 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
>> @@ -315,7 +315,7 @@ static void enh_desc_release_tx_desc(struct
>> dma_desc *p, int mode)
>> static void enh_desc_prepare_tx_desc(struct dma_desc *p, int
>> is_fs, int len,
>> bool csum_flag, int mode, bool tx_own,
>> - bool ls)
>> + bool ls, unsigned int tot_pkt_len)
>> {
>> unsigned int tdes0 = le32_to_cpu(p->des0);
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
>> b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
>> index efb818ebd55e..f817f8f36569 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
>> @@ -191,7 +191,7 @@ static void ndesc_release_tx_desc(struct dma_desc
>> *p, int mode)
>> static void ndesc_prepare_tx_desc(struct dma_desc *p, int is_fs,
>> int len,
>> bool csum_flag, int mode, bool tx_own,
>> - bool ls)
>> + bool ls, unsigned int tot_pkt_len)
>> {
>> unsigned int tdes1 = le32_to_cpu(p->des1);
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
>> b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
>> index 31213e64513d..28e4b5d50ce6 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
>> @@ -59,7 +59,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff
>> *skb, int csum)
>> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
>> priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
>> - STMMAC_RING_MODE, 0, false);
>> + STMMAC_RING_MODE, 0,
>> + false, skb->len);
>> tx_q->tx_skbuff[entry] = NULL;
>> entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
>> @@ -79,7 +80,8 @@ static int stmmac_jumbo_frm(void *p, struct
>> sk_buff *skb, int csum)
>> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
>> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
>> - STMMAC_RING_MODE, 1, true);
>> + STMMAC_RING_MODE, 1,
>> + true, skb->len);
>> } else {
>> des2 = dma_map_single(priv->device, skb->data,
>> nopaged_len, DMA_TO_DEVICE);
>> @@ -91,7 +93,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff
>> *skb, int csum)
>> tx_q->tx_skbuff_dma[entry].is_jumbo = true;
>> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
>> priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
>> - STMMAC_RING_MODE, 0, true);
>> + STMMAC_RING_MODE, 0,
>> + true, skb->len);
>> }
>> tx_q->cur_tx = entry;
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> index a89f76b27ea2..5c1ebc70bebd 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>> @@ -3033,7 +3033,8 @@ static netdev_tx_t stmmac_xmit(struct sk_buff
>> *skb, struct net_device *dev)
>> /* Prepare the descriptor and set the own bit too */
>> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion,
>> - priv->mode, 1, last_segment);
>> + priv->mode, 1, last_segment,
>> + skb->len);
>> }
>> entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
>> @@ -3116,7 +3117,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff
>> *skb, struct net_device *dev)
>> /* Prepare the first descriptor setting the OWN bit too */
>> priv->hw->desc->prepare_tx_desc(first, 1, nopaged_len,
>> csum_insertion, priv->mode, 1,
>> - last_segment);
>> + last_segment, skb->len);
>> /* The own bit must be the latest setting done when
>> prepare the
>> * descriptor and then barrier is needed to make sure that
>
>

2017-04-11 08:49:05

by Joao Pinto

[permalink] [raw]
Subject: Re: [PATCH net-next] net: stmmac: set total length of the packet to be transmitted in TDES3


Hi Niklas,

?s 7:33 PM de 4/10/2017, Niklas Cassel escreveu:
> From: Niklas Cassel <[email protected]>
>
> Field FL/TPL in register TDES3 is not correctly set on GMAC4.
> TX appears to be functional on GMAC 4.10a even if this field is not set,
> however, to avoid relying on undefined behavior, set the length in TDES3.
>
> The field has a different meaning depending on if the TSE bit in TDES3
> is set or not (TSO). However, regardless of the TSE bit, the field is
> not optional. The field is already set correctly when the TSE bit is set.
>
> Since there is no limit for the number of descriptors that can be
> used for a single packet, the field should be set to the sum of
> the buffers contained in:
> [<desc with First Descriptor bit set> ... <desc n> ...
> <desc with Last Descriptor bit set>], which should be equal to skb->len.
>
> Signed-off-by: Niklas Cassel <[email protected]>

Sounds fine to me. Did you check for performance improvement? Thanks.

Joao

2017-04-11 09:10:13

by Niklas Cassel

[permalink] [raw]
Subject: Re: [PATCH net-next] net: stmmac: set total length of the packet to be transmitted in TDES3

On 04/11/2017 10:48 AM, Joao Pinto wrote:
>
> Hi Niklas,
>
> ?s 7:33 PM de 4/10/2017, Niklas Cassel escreveu:
>> From: Niklas Cassel <[email protected]>
>>
>> Field FL/TPL in register TDES3 is not correctly set on GMAC4.
>> TX appears to be functional on GMAC 4.10a even if this field is not set,
>> however, to avoid relying on undefined behavior, set the length in TDES3.
>>
>> The field has a different meaning depending on if the TSE bit in TDES3
>> is set or not (TSO). However, regardless of the TSE bit, the field is
>> not optional. The field is already set correctly when the TSE bit is set.
>>
>> Since there is no limit for the number of descriptors that can be
>> used for a single packet, the field should be set to the sum of
>> the buffers contained in:
>> [<desc with First Descriptor bit set> ... <desc n> ...
>> <desc with Last Descriptor bit set>], which should be equal to skb->len.
>>
>> Signed-off-by: Niklas Cassel <[email protected]>
>
> Sounds fine to me. Did you check for performance improvement? Thanks.
>

Hello Joao,

I could not see any difference with 1 TCP stream in iperf3

Without the patch:
# ./iperf3-armhf -c 192.168.0.1
Connecting to host 192.168.0.1, port 5201
[ 4] local 192.168.0.105 port 51878 connected to 192.168.0.1 port 5201
[ 23.486426] random: fast init done
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 61.7 MBytes 517 Mbits/sec 0 294 KBytes
[ 4] 1.00-2.00 sec 61.3 MBytes 515 Mbits/sec 0 294 KBytes
[ 26.043850] random: crng init done
[ 4] 2.00-3.00 sec 61.4 MBytes 515 Mbits/sec 0 294 KBytes
[ 4] 3.00-4.00 sec 61.0 MBytes 512 Mbits/sec 0 294 KBytes
[ 4] 4.00-5.00 sec 61.5 MBytes 516 Mbits/sec 0 294 KBytes
[ 4] 5.00-6.00 sec 61.2 MBytes 514 Mbits/sec 0 294 KBytes
[ 4] 6.00-7.00 sec 61.5 MBytes 516 Mbits/sec 0 294 KBytes
[ 4] 7.00-8.00 sec 61.4 MBytes 515 Mbits/sec 0 294 KBytes
[ 4] 8.00-9.00 sec 61.2 MBytes 514 Mbits/sec 0 294 KBytes
[ 4] 9.00-10.00 sec 61.3 MBytes 514 Mbits/sec 0 294 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth Retr
[ 4] 0.00-10.00 sec 614 MBytes 515 Mbits/sec 0 sender
[ 4] 0.00-10.00 sec 613 MBytes 514 Mbits/sec receiver


With the patch:
# ./iperf3-armhf -c 192.168.0.1
Connecting to host 192.168.0.1, port 5201
[ 4] local 192.168.0.105 port 37696 connected to 192.168.0.1 port 5201
[ 85.266262] random: fast init done
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 62.1 MBytes 520 Mbits/sec 0 288 KBytes
[ 4] 1.00-2.00 sec 61.0 MBytes 512 Mbits/sec 0 288 KBytes
[ 87.782547] random: crng init done
[ 4] 2.00-3.00 sec 61.3 MBytes 515 Mbits/sec 0 300 KBytes
[ 4] 3.00-4.00 sec 61.1 MBytes 512 Mbits/sec 0 300 KBytes
[ 4] 4.00-5.00 sec 61.4 MBytes 515 Mbits/sec 0 300 KBytes
[ 4] 5.00-6.00 sec 61.1 MBytes 513 Mbits/sec 0 300 KBytes
[ 4] 6.00-7.00 sec 61.1 MBytes 513 Mbits/sec 0 300 KBytes
[ 4] 7.00-8.00 sec 61.6 MBytes 517 Mbits/sec 0 300 KBytes
[ 4] 8.00-9.00 sec 61.3 MBytes 515 Mbits/sec 0 300 KBytes
[ 4] 9.00-10.00 sec 61.6 MBytes 517 Mbits/sec 0 300 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth Retr
[ 4] 0.00-10.00 sec 614 MBytes 515 Mbits/sec 0 sender
[ 4] 0.00-10.00 sec 613 MBytes 514 Mbits/sec receiver


Note that the results above are with TSO off.
With TSO on, I get 921 Mbps.
However, the patch should not affect the case where TSO is on.


Regards,
Niklas

2017-04-11 12:41:37

by Peppe CAVALLARO

[permalink] [raw]
Subject: Re: [PATCH net-next] net: stmmac: set total length of the packet to be transmitted in TDES3

On 4/10/2017 8:33 PM, Niklas Cassel wrote:
> From: Niklas Cassel <[email protected]>
>
> Field FL/TPL in register TDES3 is not correctly set on GMAC4.
> TX appears to be functional on GMAC 4.10a even if this field is not set,
> however, to avoid relying on undefined behavior, set the length in TDES3.
>
> The field has a different meaning depending on if the TSE bit in TDES3
> is set or not (TSO). However, regardless of the TSE bit, the field is
> not optional. The field is already set correctly when the TSE bit is set.
>
> Since there is no limit for the number of descriptors that can be
> used for a single packet, the field should be set to the sum of
> the buffers contained in:
> [<desc with First Descriptor bit set> ... <desc n> ...
> <desc with Last Descriptor bit set>], which should be equal to skb->len.
>
> Signed-off-by: Niklas Cassel <[email protected]>

Acked-by: Giuseppe Cavallaro <[email protected]>

> ---
> drivers/net/ethernet/stmicro/stmmac/chain_mode.c | 6 +++---
> drivers/net/ethernet/stmicro/stmmac/common.h | 2 +-
> drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c | 3 ++-
> drivers/net/ethernet/stmicro/stmmac/enh_desc.c | 2 +-
> drivers/net/ethernet/stmicro/stmmac/norm_desc.c | 2 +-
> drivers/net/ethernet/stmicro/stmmac/ring_mode.c | 9 ++++++---
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++--
> 7 files changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
> index 37881f81319e..e93c40b4631e 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
> @@ -52,7 +52,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
> tx_q->tx_skbuff_dma[entry].len = bmax;
> /* do not close the descriptor and do not set own bit */
> priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
> - 0, false);
> + 0, false, skb->len);
>
> while (len != 0) {
> tx_q->tx_skbuff[entry] = NULL;
> @@ -70,7 +70,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
> tx_q->tx_skbuff_dma[entry].len = bmax;
> priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
> STMMAC_CHAIN_MODE, 1,
> - false);
> + false, skb->len);
> len -= bmax;
> i++;
> } else {
> @@ -85,7 +85,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
> /* last descriptor can be set now */
> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
> STMMAC_CHAIN_MODE, 1,
> - true);
> + true, skb->len);
> len = 0;
> }
> }
> diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
> index 90d28bcad880..b7ce3fbb5375 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/common.h
> +++ b/drivers/net/ethernet/stmicro/stmmac/common.h
> @@ -373,7 +373,7 @@ struct stmmac_desc_ops {
> /* Invoked by the xmit function to prepare the tx descriptor */
> void (*prepare_tx_desc) (struct dma_desc *p, int is_fs, int len,
> bool csum_flag, int mode, bool tx_own,
> - bool ls);
> + bool ls, unsigned int tot_pkt_len);
> void (*prepare_tso_tx_desc)(struct dma_desc *p, int is_fs, int len1,
> int len2, bool tx_own, bool ls,
> unsigned int tcphdrlen,
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> index 843ec69222ea..aa6476439aee 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
> @@ -304,12 +304,13 @@ static void dwmac4_rd_init_tx_desc(struct dma_desc *p, int mode, int end)
>
> static void dwmac4_rd_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
> bool csum_flag, int mode, bool tx_own,
> - bool ls)
> + bool ls, unsigned int tot_pkt_len)
> {
> unsigned int tdes3 = le32_to_cpu(p->des3);
>
> p->des2 |= cpu_to_le32(len & TDES2_BUFFER1_SIZE_MASK);
>
> + tdes3 |= tot_pkt_len & TDES3_PACKET_SIZE_MASK;
> if (is_fs)
> tdes3 |= TDES3_FIRST_DESCRIPTOR;
> else
> diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
> index 323b59ec74a3..7546b3664113 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c
> @@ -315,7 +315,7 @@ static void enh_desc_release_tx_desc(struct dma_desc *p, int mode)
>
> static void enh_desc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
> bool csum_flag, int mode, bool tx_own,
> - bool ls)
> + bool ls, unsigned int tot_pkt_len)
> {
> unsigned int tdes0 = le32_to_cpu(p->des0);
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
> index efb818ebd55e..f817f8f36569 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c
> @@ -191,7 +191,7 @@ static void ndesc_release_tx_desc(struct dma_desc *p, int mode)
>
> static void ndesc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
> bool csum_flag, int mode, bool tx_own,
> - bool ls)
> + bool ls, unsigned int tot_pkt_len)
> {
> unsigned int tdes1 = le32_to_cpu(p->des1);
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
> index 31213e64513d..28e4b5d50ce6 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
> @@ -59,7 +59,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
>
> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
> priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
> - STMMAC_RING_MODE, 0, false);
> + STMMAC_RING_MODE, 0,
> + false, skb->len);
> tx_q->tx_skbuff[entry] = NULL;
> entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
>
> @@ -79,7 +80,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
>
> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
> - STMMAC_RING_MODE, 1, true);
> + STMMAC_RING_MODE, 1,
> + true, skb->len);
> } else {
> des2 = dma_map_single(priv->device, skb->data,
> nopaged_len, DMA_TO_DEVICE);
> @@ -91,7 +93,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
> tx_q->tx_skbuff_dma[entry].is_jumbo = true;
> desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
> priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
> - STMMAC_RING_MODE, 0, true);
> + STMMAC_RING_MODE, 0,
> + true, skb->len);
> }
>
> tx_q->cur_tx = entry;
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index a89f76b27ea2..5c1ebc70bebd 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -3033,7 +3033,8 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
>
> /* Prepare the descriptor and set the own bit too */
> priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion,
> - priv->mode, 1, last_segment);
> + priv->mode, 1, last_segment,
> + skb->len);
> }
>
> entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
> @@ -3116,7 +3117,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
> /* Prepare the first descriptor setting the OWN bit too */
> priv->hw->desc->prepare_tx_desc(first, 1, nopaged_len,
> csum_insertion, priv->mode, 1,
> - last_segment);
> + last_segment, skb->len);
>
> /* The own bit must be the latest setting done when prepare the
> * descriptor and then barrier is needed to make sure that


2017-04-13 16:40:29

by David Miller

[permalink] [raw]
Subject: Re: [PATCH net-next] net: stmmac: set total length of the packet to be transmitted in TDES3

From: Niklas Cassel <[email protected]>
Date: Mon, 10 Apr 2017 20:33:29 +0200

> From: Niklas Cassel <[email protected]>
>
> Field FL/TPL in register TDES3 is not correctly set on GMAC4.
> TX appears to be functional on GMAC 4.10a even if this field is not set,
> however, to avoid relying on undefined behavior, set the length in TDES3.
>
> The field has a different meaning depending on if the TSE bit in TDES3
> is set or not (TSO). However, regardless of the TSE bit, the field is
> not optional. The field is already set correctly when the TSE bit is set.
>
> Since there is no limit for the number of descriptors that can be
> used for a single packet, the field should be set to the sum of
> the buffers contained in:
> [<desc with First Descriptor bit set> ... <desc n> ...
> <desc with Last Descriptor bit set>], which should be equal to skb->len.
>
> Signed-off-by: Niklas Cassel <[email protected]>

Applied, thanks.