2020-05-16 10:39:08

by Malcolm Priestley

[permalink] [raw]
Subject: [PATCH 1/4] staging: vt6656: Use sk_buff buffer for tx header

mac80211 can provide space for the driver to put a tx header on
the skb buffer instead coping the entire frame on to a local
buffer with the header.

To use this extra_tx_headroom must be set in mac80211 with the largest
possible header which is struct vnt_tx_buffer.

The driver has 8 possible combinations of tx header size which
are found in vnt_get_hdr_size replacing vnt_mac_hdr_pos.

Signed-off-by: Malcolm Priestley <[email protected]>
---
drivers/staging/vt6656/device.h | 1 +
drivers/staging/vt6656/main_usb.c | 1 +
drivers/staging/vt6656/rxtx.c | 91 ++++++++++++++++++-------------
drivers/staging/vt6656/rxtx.h | 8 ++-
drivers/staging/vt6656/usbpipe.c | 2 +-
5 files changed, 61 insertions(+), 42 deletions(-)

diff --git a/drivers/staging/vt6656/device.h b/drivers/staging/vt6656/device.h
index d19d802b5d4f..074b98dfac91 100644
--- a/drivers/staging/vt6656/device.h
+++ b/drivers/staging/vt6656/device.h
@@ -240,6 +240,7 @@ struct vnt_usb_send_context {
struct sk_buff *skb;
struct urb *urb;
struct ieee80211_hdr *hdr;
+ void *tx_buffer;
unsigned int buf_len;
u32 frame_len;
u16 tx_hdr_size;
diff --git a/drivers/staging/vt6656/main_usb.c b/drivers/staging/vt6656/main_usb.c
index b5790d4d7152..930ee424ecdf 100644
--- a/drivers/staging/vt6656/main_usb.c
+++ b/drivers/staging/vt6656/main_usb.c
@@ -1053,6 +1053,7 @@ vt6656_probe(struct usb_interface *intf, const struct usb_device_id *id)
ieee80211_hw_set(priv->hw, SUPPORTS_PS);
ieee80211_hw_set(priv->hw, PS_NULLFUNC_STACK);

+ priv->hw->extra_tx_headroom = sizeof(struct vnt_tx_buffer);
priv->hw->max_signal = 100;

SET_IEEE80211_DEV(priv->hw, &intf->dev);
diff --git a/drivers/staging/vt6656/rxtx.c b/drivers/staging/vt6656/rxtx.c
index 8348ffe6ebfa..792833f8192a 100644
--- a/drivers/staging/vt6656/rxtx.c
+++ b/drivers/staging/vt6656/rxtx.c
@@ -188,19 +188,6 @@ static __le16 vnt_get_cts_duration(struct vnt_usb_send_context *context)
context->frame_len, info);
}

-static u16 vnt_mac_hdr_pos(struct vnt_usb_send_context *tx_context,
- struct ieee80211_hdr *hdr)
-{
- u8 *head = tx_context->data + offsetof(struct vnt_tx_buffer, fifo_head);
- u8 *hdr_pos = (u8 *)hdr;
-
- tx_context->hdr = hdr;
- if (!tx_context->hdr)
- return 0;
-
- return (u16)(hdr_pos - head);
-}
-
static void vnt_rxtx_datahead_g(struct vnt_usb_send_context *tx_context,
struct vnt_tx_datahead_g *buf)
{
@@ -221,8 +208,6 @@ static void vnt_rxtx_datahead_g(struct vnt_usb_send_context *tx_context,
buf->time_stamp_off_a = vnt_time_stamp_off(priv, rate);
buf->time_stamp_off_b = vnt_time_stamp_off(priv,
priv->top_cck_basic_rate);
-
- tx_context->tx_hdr_size = vnt_mac_hdr_pos(tx_context, &buf->hdr);
}

static void vnt_rxtx_datahead_ab(struct vnt_usb_send_context *tx_context,
@@ -241,8 +226,6 @@ static void vnt_rxtx_datahead_ab(struct vnt_usb_send_context *tx_context,
/* Get Duration and TimeStampOff */
buf->duration = hdr->duration_id;
buf->time_stamp_off = vnt_time_stamp_off(priv, rate);
-
- tx_context->tx_hdr_size = vnt_mac_hdr_pos(tx_context, &buf->hdr);
}

static void vnt_fill_ieee80211_rts(struct vnt_usb_send_context *tx_context,
@@ -479,6 +462,39 @@ static void vnt_fill_txkey(struct vnt_usb_send_context *tx_context,
}
}

+static u16 vnt_get_hdr_size(struct ieee80211_tx_info *info)
+{
+ u16 size = sizeof(struct vnt_tx_datahead_ab);
+
+ if (info->control.use_cts_prot) {
+ if (info->control.use_rts)
+ size = sizeof(struct vnt_rts_g);
+ else
+ size = sizeof(struct vnt_cts);
+ } else if (info->control.use_rts) {
+ size = sizeof(struct vnt_rts_ab);
+ }
+
+ if (info->control.hw_key) {
+ if (info->control.hw_key->cipher == WLAN_CIPHER_SUITE_CCMP)
+ size += sizeof(struct vnt_mic_hdr);
+ }
+
+ /* Get rrv_time header */
+ if (info->control.use_cts_prot) {
+ if (info->control.use_rts)
+ size += sizeof(struct vnt_rrv_time_rts);
+ else
+ size += sizeof(struct vnt_rrv_time_cts);
+ } else {
+ size += sizeof(struct vnt_rrv_time_ab);
+ }
+
+ size += sizeof(struct vnt_tx_fifo_head);
+
+ return size;
+}
+
int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
@@ -531,12 +547,29 @@ int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb)
tx_context->need_ack = false;
tx_context->frame_len = skb->len + 4;
tx_context->tx_rate = rate->hw_value;
+ tx_context->hdr = hdr;

spin_unlock_irqrestore(&priv->lock, flags);

- tx_buffer = (struct vnt_tx_buffer *)tx_context->data;
- tx_buffer_head = &tx_buffer->fifo_head;
+ tx_header_size = vnt_get_hdr_size(info);
tx_body_size = skb->len;
+ tx_bytes = tx_header_size + tx_body_size;
+ tx_header_size += sizeof(struct vnt_tx_usb_header);
+
+ tx_buffer = skb_push(skb, tx_header_size);
+ tx_buffer_head = &tx_buffer->fifo_head;
+
+ /* Fill USB header */
+ tx_buffer->usb.tx_byte_count = cpu_to_le16(tx_bytes);
+ tx_buffer->usb.pkt_no = tx_context->pkt_no;
+ tx_buffer->usb.type = 0x00;
+
+ tx_context->type = CONTEXT_DATA_PACKET;
+ tx_context->tx_buffer = tx_buffer;
+ tx_context->buf_len = skb->len;
+
+ /* Return skb->data to mac80211 header */
+ skb_pull(skb, tx_header_size);

/*Set fifo controls */
if (pkt_type == PK_TYPE_11A)
@@ -603,18 +636,8 @@ int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb)
vnt_generate_tx_parameter(tx_context, tx_buffer, &mic_hdr,
need_mic, need_rts);

- tx_header_size = tx_context->tx_hdr_size;
- if (!tx_header_size) {
- tx_context->in_use = false;
- return -ENOMEM;
- }
-
tx_buffer_head->frag_ctl |= cpu_to_le16(FRAGCTL_NONFRAG);

- tx_bytes = tx_header_size + tx_body_size;
-
- memcpy(tx_context->hdr, skb->data, tx_body_size);
-
if (info->control.hw_key) {
tx_key = info->control.hw_key;
if (tx_key->keylen > 0)
@@ -625,15 +648,6 @@ int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb)
priv->seq_counter = (le16_to_cpu(hdr->seq_ctrl) &
IEEE80211_SCTL_SEQ) >> 4;

- tx_buffer->tx_byte_count = cpu_to_le16(tx_bytes);
- tx_buffer->pkt_no = tx_context->pkt_no;
- tx_buffer->type = 0x00;
-
- tx_bytes += 4;
-
- tx_context->type = CONTEXT_DATA_PACKET;
- tx_context->buf_len = tx_bytes;
-
spin_lock_irqsave(&priv->lock, flags);

if (vnt_tx_context(priv, tx_context)) {
@@ -725,6 +739,7 @@ static int vnt_beacon_xmit(struct vnt_private *priv, struct sk_buff *skb)
beacon_buffer->type = 0x01;

context->type = CONTEXT_BEACON_PACKET;
+ context->tx_buffer = &context->data;
context->buf_len = count + 4; /* USB header */

spin_lock_irqsave(&priv->lock, flags);
diff --git a/drivers/staging/vt6656/rxtx.h b/drivers/staging/vt6656/rxtx.h
index 3c36a4b893dc..819b45394673 100644
--- a/drivers/staging/vt6656/rxtx.h
+++ b/drivers/staging/vt6656/rxtx.h
@@ -77,14 +77,12 @@ struct vnt_tx_datahead_g {
__le16 duration_a;
__le16 time_stamp_off_b;
__le16 time_stamp_off_a;
- struct ieee80211_hdr hdr;
} __packed;

struct vnt_tx_datahead_ab {
struct vnt_phy_field ab;
__le16 duration;
__le16 time_stamp_off;
- struct ieee80211_hdr hdr;
} __packed;

/* RTS buffer header */
@@ -161,10 +159,14 @@ struct vnt_tx_fifo_head {
__le16 current_rate;
} __packed;

-struct vnt_tx_buffer {
+struct vnt_tx_usb_header {
u8 type;
u8 pkt_no;
__le16 tx_byte_count;
+} __packed;
+
+struct vnt_tx_buffer {
+ struct vnt_tx_usb_header usb;
struct vnt_tx_fifo_head fifo_head;
union vnt_tx_head tx_head;
} __packed;
diff --git a/drivers/staging/vt6656/usbpipe.c b/drivers/staging/vt6656/usbpipe.c
index 06dedf291db2..904645fa0eb0 100644
--- a/drivers/staging/vt6656/usbpipe.c
+++ b/drivers/staging/vt6656/usbpipe.c
@@ -466,7 +466,7 @@ int vnt_tx_context(struct vnt_private *priv,
usb_fill_bulk_urb(urb,
priv->usb,
usb_sndbulkpipe(priv->usb, 3),
- context->data,
+ context->tx_buffer,
context->buf_len,
vnt_tx_context_complete,
context);
--
2.25.1