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[net-next,v2,2/8] ravb: Add skb_sz to struct ravb_hw_info

Message ID 20210802102654.5996-3-biju.das.jz@bp.renesas.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series Add Gigabit Ethernet driver support | expand

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Commit Message

Biju Das Aug. 2, 2021, 10:26 a.m. UTC 
The maximum descriptor size that can be specified on the reception side for
R-Car is 2048 bytes, whereas for RZ/G2L it is 8096.

Add the skb_size variable to struct ravb_hw_info for allocating different
skb buffer sizes for R-Car and RZ/G2L using the netdev_alloc_skb function.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v2:
 * Incorporated Andrew and Sergei's review comments for making it smaller patch
   and provided detailed description.
---
 drivers/net/ethernet/renesas/ravb.h      |  1 +
 drivers/net/ethernet/renesas/ravb_main.c | 10 ++++++----
 2 files changed, 7 insertions(+), 4 deletions(-)

Comments

Andrew Lunn Aug. 2, 2021, 3:08 p.m. UTC | #1 
On Mon, Aug 02, 2021 at 11:26:48AM +0100, Biju Das wrote:
> The maximum descriptor size that can be specified on the reception side for
> R-Car is 2048 bytes, whereas for RZ/G2L it is 8096.
> 
> Add the skb_size variable to struct ravb_hw_info for allocating different
> skb buffer sizes for R-Car and RZ/G2L using the netdev_alloc_skb function.
> 
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew
Sergey Shtylyov Aug. 2, 2021, 8:54 p.m. UTC | #2 
On 8/2/21 1:26 PM, Biju Das wrote:

> The maximum descriptor size that can be specified on the reception side for
> R-Car is 2048 bytes, whereas for RZ/G2L it is 8096.
> 
> Add the skb_size variable to struct ravb_hw_info for allocating different
> skb buffer sizes for R-Car and RZ/G2L using the netdev_alloc_skb function.
> 
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> v2:
>  * Incorporated Andrew and Sergei's review comments for making it smaller patch
>    and provided detailed description.
> ---
>  drivers/net/ethernet/renesas/ravb.h      |  1 +
>  drivers/net/ethernet/renesas/ravb_main.c | 10 ++++++----
>  2 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
> index cfb972c05b34..16d1711a0731 100644
> --- a/drivers/net/ethernet/renesas/ravb.h
> +++ b/drivers/net/ethernet/renesas/ravb.h
> @@ -991,6 +991,7 @@ enum ravb_chip_id {
>  struct ravb_hw_info {
>  	enum ravb_chip_id chip_id;
>  	int num_tx_desc;
> +	size_t skb_sz;

   Bad naming -- refers to software ISO hatdware, I suggest max_rx_len or s/th of that sort.

[...]

MBR, Sergei
Biju Das Aug. 3, 2021, 7:13 a.m. UTC | #3 
Hi Sergei,

Thanks for the feedback.

> Subject: Re: [PATCH net-next v2 2/8] ravb: Add skb_sz to struct
> ravb_hw_info
> 
> On 8/2/21 1:26 PM, Biju Das wrote:
> 
> > The maximum descriptor size that can be specified on the reception
> > side for R-Car is 2048 bytes, whereas for RZ/G2L it is 8096.
> >
> > Add the skb_size variable to struct ravb_hw_info for allocating
> > different skb buffer sizes for R-Car and RZ/G2L using the
> netdev_alloc_skb function.
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > ---
> > v2:
> >  * Incorporated Andrew and Sergei's review comments for making it
> smaller patch
> >    and provided detailed description.
> > ---
> >  drivers/net/ethernet/renesas/ravb.h      |  1 +
> >  drivers/net/ethernet/renesas/ravb_main.c | 10 ++++++----
> >  2 files changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/renesas/ravb.h
> > b/drivers/net/ethernet/renesas/ravb.h
> > index cfb972c05b34..16d1711a0731 100644
> > --- a/drivers/net/ethernet/renesas/ravb.h
> > +++ b/drivers/net/ethernet/renesas/ravb.h
> > @@ -991,6 +991,7 @@ enum ravb_chip_id {  struct ravb_hw_info {
> >  	enum ravb_chip_id chip_id;
> >  	int num_tx_desc;
> > +	size_t skb_sz;
> 
>    Bad naming -- refers to software ISO hatdware, I suggest max_rx_len or
> s/th of that sort.

From the api description
*	netdev_alloc_skb - allocate an skbuff for rx on a specific device
*	@length: length to allocate

Since it allocates skbuff, I thought skb_sz (size of skb buffer) is a good name.

Is there any restriction in Linux, not to use skb_sz because of 
"software ISO hardware" as you mentioned?
I may have chosen bad name because of this restriction. 

Please correct me, if that is the case.

Regards,
Biju
diff mbox series

Patch

diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index cfb972c05b34..16d1711a0731 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -991,6 +991,7 @@  enum ravb_chip_id {
 struct ravb_hw_info {
 	enum ravb_chip_id chip_id;
 	int num_tx_desc;
+	size_t skb_sz;
 };
 
 struct ravb_private {
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index ffbd224d8780..08146c1975e5 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -339,6 +339,7 @@  static void ravb_ring_format(struct net_device *ndev, int q)
 static int ravb_ring_init(struct net_device *ndev, int q)
 {
 	struct ravb_private *priv = netdev_priv(ndev);
+	const struct ravb_hw_info *info = priv->info;
 	int num_tx_desc = priv->num_tx_desc;
 	struct sk_buff *skb;
 	int ring_size;
@@ -353,7 +354,7 @@  static int ravb_ring_init(struct net_device *ndev, int q)
 		goto error;
 
 	for (i = 0; i < priv->num_rx_ring[q]; i++) {
-		skb = netdev_alloc_skb(ndev, RX_BUF_SZ + RAVB_ALIGN - 1);
+		skb = netdev_alloc_skb(ndev, info->skb_sz);
 		if (!skb)
 			goto error;
 		ravb_set_buffer_align(skb);
@@ -535,6 +536,7 @@  static void ravb_rx_csum(struct sk_buff *skb)
 static bool ravb_rx(struct net_device *ndev, int *quota, int q)
 {
 	struct ravb_private *priv = netdev_priv(ndev);
+	const struct ravb_hw_info *info = priv->info;
 	int entry = priv->cur_rx[q] % priv->num_rx_ring[q];
 	int boguscnt = (priv->dirty_rx[q] + priv->num_rx_ring[q]) -
 			priv->cur_rx[q];
@@ -619,9 +621,7 @@  static bool ravb_rx(struct net_device *ndev, int *quota, int q)
 		desc->ds_cc = cpu_to_le16(RX_BUF_SZ);
 
 		if (!priv->rx_skb[q][entry]) {
-			skb = netdev_alloc_skb(ndev,
-					       RX_BUF_SZ +
-					       RAVB_ALIGN - 1);
+			skb = netdev_alloc_skb(ndev, info->skb_sz);
 			if (!skb)
 				break;	/* Better luck next round. */
 			ravb_set_buffer_align(skb);
@@ -1927,11 +1927,13 @@  static int ravb_mdio_release(struct ravb_private *priv)
 static const struct ravb_hw_info ravb_gen3_hw_info = {
 	.chip_id = RCAR_GEN3,
 	.num_tx_desc = NUM_TX_DESC_GEN3,
+	.skb_sz = RX_BUF_SZ + RAVB_ALIGN - 1,
 };
 
 static const struct ravb_hw_info ravb_gen2_hw_info = {
 	.chip_id = RCAR_GEN2,
 	.num_tx_desc = NUM_TX_DESC_GEN2,
+	.skb_sz = RX_BUF_SZ + RAVB_ALIGN - 1,
 };
 
 static const struct of_device_id ravb_match_table[] = {