rt2x00: Fix ieee80211 payload alignment
PATCH 1/1 rt2x00: Fix ieee80211 payload alignment
As Johannes Berg indicated, the NET_IP_ALIGN doesn't need to be used for ieee80211 frames. This means we can simplify the alignment calculation to just use the result of the header size modulus 4 as frame alignment.
Furthermore we shouldn't use NET_IP_ALIGN in rt2x00usb because it could be 0 on some architectures and we absolutely need to have 2 bytes reserved for possible aligning.
Signed-off-by Ivo van Doorn<[email protected]>
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John, please push this patch upstream to 2.6.24 as well. This patch fixes a bug introduced in:
rt2x00: Put 802.11 data on 4 byte boundary
drivers/net/wireless/rt2x00/rt2x00pci.c | 2 +- drivers/net/wireless/rt2x00/rt2x00usb.c | 11 +++++++++-- 2 files changed, 10 insertions(+), 3 deletions(-)
drivers/net/wireless/rt2x00/rt2x00pci.c +1 -1
@@ -157,7 +157,7 @@ void rt2x00pci_rxdone(struct rt2x00_dev *rt2x00dev)* The data behind the ieee80211 header must be * aligned on a 4 byte boundary. */ - align =NET_IP_ALIGN + (2 * (header_size %4 ==0 )); + align = header_size %4 ;/* * Allocate the sk_buffer, initialize it and copy
drivers/net/wireless/rt2x00/rt2x00usb.c +9 -2
@@ -271,13 +271,20 @@ static void rt2x00usb_interrupt_rxdone(struct urb *urb)* Allocate a new sk buffer to replace the current one. * If allocation fails, we should drop the current frame * so we can recycle the existing sk buffer for the new frame. +* 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. */ frame_size = entry->ring->data_size + entry->ring->desc_size; - skb =dev_alloc_skb (frame_size +NET_IP_ALIGN ); + skb =dev_alloc_skb (frame_size +2 );if (!skb) goto skip_entry; -skb_reserve (skb,NET_IP_ALIGN ); +skb_reserve (skb,2 );skb_put (skb, frame_size);/*
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1.5.3.8