__le32 *rxd =
(__le32 *)(entry->skb->data +
(priv_rx->urb->actual_length - entry->queue->desc_size));
- unsigned int offset = entry->queue->desc_size + 2;
u32 word0;
u32 word1;
/*
- * Copy descriptor to the available headroom inside the skbuffer.
+ * Copy descriptor to the skb->cb array, this has 2 benefits:
+ * 1) Each descriptor word is 4 byte aligned.
+ * 2) Descriptor is safe from moving of frame data in rt2x00usb.
*/
- skb_push(entry->skb, offset);
- memcpy(entry->skb->data, rxd, entry->queue->desc_size);
- rxd = (__le32 *)entry->skb->data;
+ skbdesc->desc_len =
+ min_t(u16, entry->queue->desc_size, sizeof(entry->skb->cb));
+ memcpy(entry->skb->cb, rxd, skbdesc->desc_len);
+ skbdesc->desc = entry->skb->cb;
+ rxd = (__le32 *)skbdesc->desc;
/*
- * The descriptor is now aligned to 4 bytes and thus it is
- * now safe to read it on all architectures.
+ * It is now safe to read the descriptor on all architectures.
*/
rt2x00_desc_read(rxd, 0, &word0);
rt2x00_desc_read(rxd, 1, &word1);
/*
* Adjust the skb memory window to the frame boundaries.
*/
- skb_pull(entry->skb, offset);
skb_trim(entry->skb, rxdesc->size);
-
- /*
- * Set descriptor and data pointer.
- */
skbdesc->data = entry->skb->data;
skbdesc->data_len = rxdesc->size;
- skbdesc->desc = rxd;
- skbdesc->desc_len = entry->queue->desc_size;
}
/*
{
struct sk_buff *skb;
unsigned int frame_size;
+ unsigned int reserved_size;
/*
- * As alignment we use 2 and not NET_IP_ALIGN because we need
- * to be sure we have 2 bytes room in the head. (NET_IP_ALIGN
- * can be 0 on some hardware). We use these 2 bytes for frame
- * alignment later, we assume that the chance that
- * header_size % 4 == 2 is bigger then header_size % 2 == 0
- * and thus optimize alignment by reserving the 2 bytes in
- * advance.
+ * The frame size includes descriptor size, because the
+ * hardware directly receive the frame into the skbuffer.
*/
frame_size = queue->data_size + queue->desc_size;
- skb = dev_alloc_skb(queue->desc_size + frame_size + 2);
+
+ /*
+ * For the allocation we should keep a few things in mind:
+ * 1) 4byte alignment of 802.11 payload
+ *
+ * For (1) we need at most 4 bytes to guarentee the correct
+ * alignment. We are going to optimize the fact that the chance
+ * that the 802.11 header_size % 4 == 2 is much bigger then
+ * anything else. However since we need to move the frame up
+ * to 3 bytes to the front, which means we need to preallocate
+ * 6 bytes.
+ */
+ reserved_size = 6;
+
+ /*
+ * Allocate skbuffer.
+ */
+ skb = dev_alloc_skb(frame_size + reserved_size);
if (!skb)
return NULL;
- skb_reserve(skb, queue->desc_size + 2);
+ skb_reserve(skb, reserved_size);
skb_put(skb, frame_size);
return skb;
struct sk_buff *skb;
struct skb_frame_desc *skbdesc;
struct rxdone_entry_desc rxdesc;
- int header_size;
+ unsigned int header_size;
+ unsigned int align;
if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags) ||
!test_and_clear_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))
memset(&rxdesc, 0, sizeof(rxdesc));
rt2x00dev->ops->lib->fill_rxdone(entry, &rxdesc);
+ header_size = ieee80211_get_hdrlen_from_skb(entry->skb);
+
/*
* The data behind the ieee80211 header must be
- * aligned on a 4 byte boundary.
+ * aligned on a 4 byte boundary. We already reserved
+ * 2 bytes for header_size % 4 == 2 optimization.
+ * To determine the number of bytes which the data
+ * should be moved to the left, we must add these
+ * 2 bytes to the header_size.
*/
- header_size = ieee80211_get_hdrlen_from_skb(entry->skb);
- if (header_size % 4 == 0) {
- skb_push(entry->skb, 2);
- memmove(entry->skb->data, entry->skb->data + 2,
- entry->skb->len - 2);
- skbdesc->data = entry->skb->data;
- skb_trim(entry->skb,entry->skb->len - 2);
+ align = (header_size + 2) % 4;
+
+ if (align) {
+ skb_push(entry->skb, align);
+ /* Move entire frame in 1 command */
+ memmove(entry->skb->data, entry->skb->data + align,
+ rxdesc.size);
}
+ /* Update data pointers, trim buffer to correct size */
+ skbdesc->data = entry->skb->data;
+ skb_trim(entry->skb, rxdesc.size);
+
/*
* Allocate a new sk buffer to replace the current one.
* If allocation fails, we should drop the current frame
{
struct skb_frame_desc *skbdesc = get_skb_frame_desc(entry->skb);
__le32 *rxd = (__le32 *)entry->skb->data;
- unsigned int offset = entry->queue->desc_size + 2;
u32 word0;
u32 word1;
/*
- * Copy descriptor to the available headroom inside the skbuffer.
+ * Copy descriptor to the skb->cb array, this has 2 benefits:
+ * 1) Each descriptor word is 4 byte aligned.
+ * 2) Descriptor is safe from moving of frame data in rt2x00usb.
*/
- skb_push(entry->skb, offset);
- memcpy(entry->skb->data, rxd, entry->queue->desc_size);
- rxd = (__le32 *)entry->skb->data;
+ skbdesc->desc_len =
+ min_t(u16, entry->queue->desc_size, sizeof(entry->skb->cb));
+ memcpy(entry->skb->cb, rxd, skbdesc->desc_len);
+ skbdesc->desc = entry->skb->cb;
+ rxd = (__le32 *)skbdesc->desc;
/*
- * The descriptor is now aligned to 4 bytes and thus it is
- * now safe to read it on all architectures.
+ * It is now safe to read the descriptor on all architectures.
*/
rt2x00_desc_read(rxd, 0, &word0);
rt2x00_desc_read(rxd, 1, &word1);
rxdesc->dev_flags |= RXDONE_MY_BSS;
/*
- * Adjust the skb memory window to the frame boundaries.
+ * Set skb pointers, and update frame information.
*/
- skb_pull(entry->skb, offset + entry->queue->desc_size);
+ skb_pull(entry->skb, entry->queue->desc_size);
skb_trim(entry->skb, rxdesc->size);
-
- /*
- * Set descriptor and data pointer.
- */
skbdesc->data = entry->skb->data;
skbdesc->data_len = rxdesc->size;
- skbdesc->desc = rxd;
- skbdesc->desc_len = entry->queue->desc_size;
}
/*
projects / linux-2.6-omap-h63xx.git / commitdiff