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Commit b4b6cda2 authored by Luis R. Rodriguez's avatar Luis R. Rodriguez Committed by John W. Linville
Browse files

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: default avatarBennyam Malavazi <Bennyam.Malavazi@atheros.com>
Signed-off-by: default avatarLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent ca0c7e51

drivers/net/wireless/ath9k/recv.c

+11 −2
Original line number Diff line number Diff line
@@ -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;