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authorLuis R. Rodriguez <lrodriguez@atheros.com>2008-11-20 17:15:13 -0800
committerJohn W. Linville <linville@tuxdriver.com>2008-11-25 16:13:08 -0500
commitb4b6cda2298b0c9a0af902312184b775b8867c65 (patch)
tree7357a39a07d5cb7a4360161fb8acaa09a198c77d /drivers
parentca0c7e5101fd4f37fed8e851709f08580b92fbb3 (diff)
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 <Bennyam.Malavazi@atheros.com> Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/wireless/ath9k/recv.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/net/wireless/ath9k/recv.c b/drivers/net/wireless/ath9k/recv.c
index ad5f88879dc..504a0444d89 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;