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Message-ID: <5500B958.2020101@pengutronix.de>
Date: Wed, 11 Mar 2015 22:53:28 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: "Ahmed S. Darwish" <darwish.07@...il.com>,
Olivier Sobrie <olivier@...rie.be>,
Oliver Hartkopp <socketcan@...tkopp.net>,
Wolfgang Grandegger <wg@...ndegger.com>,
Andri Yngvason <andri.yngvason@...el.com>
CC: Linux-CAN <linux-can@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 2/3] can: kvaser_usb: Utilize all possible tx URBs
On 03/11/2015 06:39 PM, Ahmed S. Darwish wrote:
> From: Ahmed S. Darwish <ahmed.darwish@...eo.com>
>
> The driver currently limits the number of outstanding, not yet
> ACKed, transfers to 16 URBs. Meanwhile, the Kvaser firmware
> provides its actual max supported number of outstanding
> transmissions in its reply to the CMD_GET_SOFTWARE_INFO message.
>
> One example is the UsbCan-II HS/LS device which reports support
> of up to 48 tx URBs instead of just 16, increasing the driver
> throughput by two-fold and reducing the possibility of -ENOBUFs.
>
> Dynamically set the max tx URBs value according to firmware
> replies.
>
> Signed-off-by: Ahmed S. Darwish <ahmed.darwish@...eo.com>
> ---
> drivers/net/can/usb/kvaser_usb.c | 55 +++++++++++++++++++++++++++-------------
> 1 file changed, 37 insertions(+), 18 deletions(-)
>
> changelog-v3: No changes
>
> diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c
> index e97a08c..30b4d47 100644
> --- a/drivers/net/can/usb/kvaser_usb.c
> +++ b/drivers/net/can/usb/kvaser_usb.c
> @@ -25,7 +25,6 @@
> #include <linux/can/dev.h>
> #include <linux/can/error.h>
>
> -#define MAX_TX_URBS 16
> #define MAX_RX_URBS 4
> #define START_TIMEOUT 1000 /* msecs */
> #define STOP_TIMEOUT 1000 /* msecs */
> @@ -456,8 +455,13 @@ struct kvaser_usb {
> struct usb_endpoint_descriptor *bulk_in, *bulk_out;
> struct usb_anchor rx_submitted;
>
> + /* @max_tx_urbs: Firmware-reported maximum number of possible
> + * outstanding transmissions on this specific Kvaser hardware. The
> + * value is also used as a sentinel for marking free URB contexts.
> + */
> u32 fw_version;
> unsigned int nchannels;
> + unsigned int max_tx_urbs;
> enum kvaser_usb_family family;
>
> bool rxinitdone;
> @@ -470,7 +474,7 @@ struct kvaser_usb_net_priv {
>
> spinlock_t tx_contexts_lock;
> int active_tx_contexts;
> - struct kvaser_usb_tx_urb_context tx_contexts[MAX_TX_URBS];
> + struct kvaser_usb_tx_urb_context *tx_contexts;
>
> struct usb_anchor tx_submitted;
> struct completion start_comp, stop_comp;
> @@ -657,9 +661,13 @@ static int kvaser_usb_get_software_info(struct kvaser_usb *dev)
> switch (dev->family) {
> case KVASER_LEAF:
> dev->fw_version = le32_to_cpu(msg.u.leaf.softinfo.fw_version);
> + dev->max_tx_urbs =
> + le16_to_cpu(msg.u.leaf.softinfo.max_outstanding_tx);
> break;
> case KVASER_USBCAN:
> dev->fw_version = le32_to_cpu(msg.u.usbcan.softinfo.fw_version);
> + dev->max_tx_urbs =
> + le16_to_cpu(msg.u.usbcan.softinfo.max_outstanding_tx);
> break;
> }
>
> @@ -715,7 +723,7 @@ static void kvaser_usb_tx_acknowledge(const struct kvaser_usb *dev,
>
> stats = &priv->netdev->stats;
>
> - context = &priv->tx_contexts[tid % MAX_TX_URBS];
> + context = &priv->tx_contexts[tid % dev->max_tx_urbs];
>
> /* Sometimes the state change doesn't come after a bus-off event */
> if (priv->can.restart_ms &&
> @@ -744,7 +752,7 @@ static void kvaser_usb_tx_acknowledge(const struct kvaser_usb *dev,
> spin_lock_irqsave(&priv->tx_contexts_lock, flags);
>
> can_get_echo_skb(priv->netdev, context->echo_index);
> - context->echo_index = MAX_TX_URBS;
> + context->echo_index = dev->max_tx_urbs;
> --priv->active_tx_contexts;
> netif_wake_queue(priv->netdev);
>
> @@ -1512,11 +1520,13 @@ error:
>
> static void kvaser_usb_reset_tx_urb_contexts(struct kvaser_usb_net_priv *priv)
> {
> - int i;
> + int i, max_tx_urbs;
> +
> + max_tx_urbs = priv->dev->max_tx_urbs;
>
> priv->active_tx_contexts = 0;
> - for (i = 0; i < MAX_TX_URBS; i++)
> - priv->tx_contexts[i].echo_index = MAX_TX_URBS;
> + for (i = 0; i < max_tx_urbs; i++)
> + priv->tx_contexts[i].echo_index = max_tx_urbs;
> }
>
> /* This method might sleep. Do not call it in the atomic context
> @@ -1702,14 +1712,14 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb,
> *msg_tx_can_flags |= MSG_FLAG_REMOTE_FRAME;
>
> spin_lock_irqsave(&priv->tx_contexts_lock, flags);
> - for (i = 0; i < ARRAY_SIZE(priv->tx_contexts); i++) {
> - if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) {
> + for (i = 0; i < dev->max_tx_urbs; i++) {
> + if (priv->tx_contexts[i].echo_index == dev->max_tx_urbs) {
> context = &priv->tx_contexts[i];
>
> context->echo_index = i;
> can_put_echo_skb(skb, netdev, context->echo_index);
> ++priv->active_tx_contexts;
> - if (priv->active_tx_contexts >= MAX_TX_URBS)
> + if (priv->active_tx_contexts >= dev->max_tx_urbs)
> netif_stop_queue(netdev);
>
> break;
> @@ -1743,7 +1753,7 @@ static netdev_tx_t kvaser_usb_start_xmit(struct sk_buff *skb,
> spin_lock_irqsave(&priv->tx_contexts_lock, flags);
>
> can_free_echo_skb(netdev, context->echo_index);
> - context->echo_index = MAX_TX_URBS;
> + context->echo_index = dev->max_tx_urbs;
> --priv->active_tx_contexts;
> netif_wake_queue(netdev);
>
> @@ -1881,7 +1891,7 @@ static int kvaser_usb_init_one(struct usb_interface *intf,
> if (err)
> return err;
>
> - netdev = alloc_candev(sizeof(*priv), MAX_TX_URBS);
> + netdev = alloc_candev(sizeof(*priv), dev->max_tx_urbs);
> if (!netdev) {
> dev_err(&intf->dev, "Cannot alloc candev\n");
> return -ENOMEM;
> @@ -1889,6 +1899,13 @@ static int kvaser_usb_init_one(struct usb_interface *intf,
>
> priv = netdev_priv(netdev);
>
> + priv->tx_contexts = kzalloc(dev->max_tx_urbs *
> + sizeof(*priv->tx_contexts), GFP_KERNEL);
> + if (!priv->tx_contexts) {
> + free_candev(netdev);
> + return -ENOMEM;
> + }
I'm missing a free for the priv->tx_contexts. I see two options:
1) use devm_kzalloc(), or
2) move struct kvaser_usb_tx_urb_context tx_contexts[]; to the end of
struct kvaser_usb_net_priv, see [1] for an example.
Without further testing, I think the correct alloc for that case
would be:
alloc_candev(sizeof(*priv + dev->max_tx_urbs *
sizeof(struct kvaser_usb_tx_urb_context))
Marc
[1] http://stackoverflow.com/questions/2060974/dynamic-array-in-struct-c
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
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