You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
96 lines
3.1 KiB
Diff
96 lines
3.1 KiB
Diff
From: Stanislaw Gruszka <sgruszka@redhat.com>
|
|
Date: Sun, 2 Nov 2014 13:38:47 +0100
|
|
Subject: [PATCH] rt2x00: do not align payload on modern H/W
|
|
|
|
RT2800 and newer hardware require padding between header and payload if
|
|
header length is not multiple of 4.
|
|
|
|
For historical reasons we also align payload to to 4 bytes boundary, but
|
|
such alignment is not needed on modern H/W.
|
|
|
|
Patch improve performance on embedded CPUs and _possibly_ fixes
|
|
skb_under_panic problems reported from time to time:
|
|
|
|
https://bugzilla.kernel.org/show_bug.cgi?id=84911
|
|
https://bugzilla.kernel.org/show_bug.cgi?id=72471
|
|
http://marc.info/?l=linux-wireless&m=139108549530402&w=2
|
|
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1087591
|
|
|
|
But we can not explain or otherwise confirm the patch fixes this panic
|
|
issue for sure.
|
|
|
|
Originally-From: Helmut Schaa <helmut.schaa@googlemail.com>
|
|
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
|
|
---
|
|
|
|
--- a/drivers/net/wireless/rt2x00/rt2x00queue.c
|
|
+++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
|
|
@@ -158,55 +158,29 @@ void rt2x00queue_align_frame(struct sk_b
|
|
skb_trim(skb, frame_length);
|
|
}
|
|
|
|
-void rt2x00queue_insert_l2pad(struct sk_buff *skb, unsigned int header_length)
|
|
+/*
|
|
+ * H/W needs L2 padding between the header and the paylod if header size
|
|
+ * is not 4 bytes aligned.
|
|
+ */
|
|
+void rt2x00queue_insert_l2pad(struct sk_buff *skb, unsigned int hdr_len)
|
|
{
|
|
- unsigned int payload_length = skb->len - header_length;
|
|
- unsigned int header_align = ALIGN_SIZE(skb, 0);
|
|
- unsigned int payload_align = ALIGN_SIZE(skb, header_length);
|
|
- unsigned int l2pad = payload_length ? L2PAD_SIZE(header_length) : 0;
|
|
+ unsigned int l2pad = (skb->len > hdr_len) ? L2PAD_SIZE(hdr_len) : 0;
|
|
|
|
- /*
|
|
- * Adjust the header alignment if the payload needs to be moved more
|
|
- * than the header.
|
|
- */
|
|
- if (payload_align > header_align)
|
|
- header_align += 4;
|
|
-
|
|
- /* There is nothing to do if no alignment is needed */
|
|
- if (!header_align)
|
|
+ if (!l2pad)
|
|
return;
|
|
|
|
- /* Reserve the amount of space needed in front of the frame */
|
|
- skb_push(skb, header_align);
|
|
-
|
|
- /*
|
|
- * Move the header.
|
|
- */
|
|
- memmove(skb->data, skb->data + header_align, header_length);
|
|
-
|
|
- /* Move the payload, if present and if required */
|
|
- if (payload_length && payload_align)
|
|
- memmove(skb->data + header_length + l2pad,
|
|
- skb->data + header_length + l2pad + payload_align,
|
|
- payload_length);
|
|
-
|
|
- /* Trim the skb to the correct size */
|
|
- skb_trim(skb, header_length + l2pad + payload_length);
|
|
+ skb_push(skb, l2pad);
|
|
+ memmove(skb->data, skb->data + l2pad, hdr_len);
|
|
}
|
|
|
|
-void rt2x00queue_remove_l2pad(struct sk_buff *skb, unsigned int header_length)
|
|
+void rt2x00queue_remove_l2pad(struct sk_buff *skb, unsigned int hdr_len)
|
|
{
|
|
- /*
|
|
- * L2 padding is only present if the skb contains more than just the
|
|
- * IEEE 802.11 header.
|
|
- */
|
|
- unsigned int l2pad = (skb->len > header_length) ?
|
|
- L2PAD_SIZE(header_length) : 0;
|
|
+ unsigned int l2pad = (skb->len > hdr_len) ? L2PAD_SIZE(hdr_len) : 0;
|
|
|
|
if (!l2pad)
|
|
return;
|
|
|
|
- memmove(skb->data + l2pad, skb->data, header_length);
|
|
+ memmove(skb->data + l2pad, skb->data, hdr_len);
|
|
skb_pull(skb, l2pad);
|
|
}
|
|
|