From b4b6cda2298b0c9a0af902312184b775b8867c65 Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Thu, 20 Nov 2008 17:15:13 -0800 Subject: [PATCH] ath9k: correct expected max RX buffer size We should only tell the hardware its capable of DMA'ing to us only what we asked dev_alloc_skb(). Prior to this it is possible a large RX'd frame could have corrupted DMA data but for us but we were saved only because we were previously also pci_map_single()'ing the same large value. The issue prior to this though was we were unmapping a smaller amount which the prior DMA patch fixed. Signed-off-by: Bennyam Malavazi Signed-off-by: Luis R. Rodriguez Signed-off-by: John W. Linville --- drivers/net/wireless/ath9k/recv.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/ath9k/recv.c b/drivers/net/wireless/ath9k/recv.c index ad5f888..504a044 100644 --- a/drivers/net/wireless/ath9k/recv.c +++ b/drivers/net/wireless/ath9k/recv.c @@ -49,10 +49,12 @@ static void ath_rx_buf_link(struct ath_softc *sc, struct ath_buf *bf) ASSERT(skb != NULL); ds->ds_vdata = skb->data; - /* setup rx descriptors */ + /* setup rx descriptors. The sc_rxbufsize here tells the harware + * how much data it can DMA to us and that we are prepared + * to process */ ath9k_hw_setuprxdesc(ah, ds, - skb_tailroom(skb), /* buffer size */ + sc->sc_rxbufsize, 0); if (sc->sc_rxlink == NULL) @@ -398,6 +400,13 @@ static struct sk_buff *ath_rxbuf_alloc(struct ath_softc *sc, * in rx'd frames. */ + /* Note: the kernel can allocate a value greater than + * what we ask it to give us. We really only need 4 KB as that + * is this hardware supports and in fact we need at least 3849 + * as that is the MAX AMSDU size this hardware supports. + * Unfortunately this means we may get 8 KB here from the + * kernel... and that is actually what is observed on some + * systems :( */ skb = dev_alloc_skb(len + sc->sc_cachelsz - 1); if (skb != NULL) { off = ((unsigned long) skb->data) % sc->sc_cachelsz; -- 2.7.4