Fix up truesize after pskb_expand_head() in wireless stack
When using a zd1211rw wireless usb stick I regularly got truesize
warnings in the kernel log.
This patch fixes those up in the wireless layer. tx.c already
did that, but not rx.c. I think my messages only came from
the middle case, but I fixed up all three users in rx.c
The underlying problem seems to be that pskb_expand_head() doesn't
manipulate truesize. Perhaps it should? I suspect more users of it have
the same problem. I didn't change the low level code because
I was afraid to break some callers, but perhaps it would be
better to do it this way. Anyways here's a patch that only
changes it in the wireless layer with minimal risk.
Patch against 2.6.28, but I think linus git still has the same
issue.
I believe this is a 2.6.28 stable candidate. I even saw
the same problem in 2.6.27.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
net/mac80211/rx.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
Index: linux-2.6.28-test/net/mac80211/rx.c
===================================================================
--- linux-2.6.28-test.orig/net/mac80211/rx.c 2008-10-24 13:35:11.000000000 +0200
+++ linux-2.6.28-test/net/mac80211/rx.c 2009-01-01 15:51:34.000000000 +0100
@@ -263,10 +263,12 @@
* probably export the length to drivers so that we can have
* them allocate enough headroom to start with.
*/
- if (skb_headroom(skb) < needed_headroom &&
- pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
- dev_kfree_skb(skb);
- return NULL;
+ if (skb_headroom(skb) < needed_headroom) {
+ if (pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
+ dev_kfree_skb(skb);
+ return NULL;
+ }
+ skb->truesize += needed_headroom;
}
} else {
/*
@@ -945,6 +947,7 @@
__skb_queue_purge(&entry->skb_list);
return RX_DROP_UNUSABLE;
}
+ rx->skb->truesize += entry->extra_len;
}
while ((skb = __skb_dequeue(&entry->skb_list))) {
memcpy(skb_put(rx->skb, skb->len), skb->data, skb->len);
@@ -1691,9 +1694,11 @@
if (rx->flags & IEEE80211_RX_CMNTR_REPORTED)
goto out_free_skb;
- if (skb_headroom(skb) < sizeof(*rthdr) &&
- pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC))
- goto out_free_skb;
+ if (skb_headroom(skb) < sizeof(*rthdr)) {
+ if (pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC))
+ goto out_free_skb;
+ skb->truesize += sizeof(*rthdr);
+ }
rthdr = (void *)skb_push(skb, sizeof(*rthdr));
memset(rthdr, 0, sizeof(*rthdr));
--
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