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ath5k: manipulate rxlink and descriptor address under rxbuf lock

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Grabbing an ath5k_buf then dropping the lock is racy because the
referenced descriptor can be obtained in another thread and released
before the buffer is handed to the hardware.  Likewise, manipulating
sc->rxlink without the lock can lead to having multiple self-linked
hardware descriptors.

Changes-licensed-under: 3-Clause-BSD

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Bob Copeland 2009-04-15 07:57:36 -04:00 committed by John W. Linville
parent c57ca81576
commit 26925042b6
1 changed files with 2 additions and 3 deletions
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5
drivers/net/wireless/ath/ath5k/base.c
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@ -1618,9 +1618,8 @@ ath5k_rx_start(struct ath5k_softc *sc)
ATH5K_DBG(sc, ATH5K_DEBUG_RESET, "cachelsz %u rxbufsize %u\n",
sc->cachelsz, sc->rxbufsize);
sc->rxlink = NULL;
spin_lock_bh(&sc->rxbuflock);
sc->rxlink = NULL;
list_for_each_entry(bf, &sc->rxbuf, list) {
ret = ath5k_rxbuf_setup(sc, bf);
if (ret != 0) {
@ -1629,9 +1628,9 @@ ath5k_rx_start(struct ath5k_softc *sc)
}
}
bf = list_first_entry(&sc->rxbuf, struct ath5k_buf, list);
ath5k_hw_set_rxdp(ah, bf->daddr);
spin_unlock_bh(&sc->rxbuflock);
ath5k_hw_set_rxdp(ah, bf->daddr);
ath5k_hw_start_rx_dma(ah); /* enable recv descriptors */
ath5k_mode_setup(sc); /* set filters, etc. */
ath5k_hw_start_rx_pcu(ah); /* re-enable PCU/DMA engine */