On Wed July 14 2010 00:32:40 Bob Copeland wrote:
> We currently trigger a reset via a tasklet when certain error
> conditions are detected so that the card will (eventually)
> restart. Unfortunately this makes locking complicated since
> reset can also be called in process context (e.g. for channel
> change). Currently nothing protects against concurrent resets,
> which can be the source of corruption bugs.
>
> Reset takes too long to spinlock the whole thing, so this
> patch moves deferred resets into the mac80211 workqueue to
> enable use of sc->lock mutex.
>
> Signed-off-by: Bob Copeland <me@xxxxxxxxxxxxxxx>
> ---
> drivers/net/wireless/ath/ath5k/base.c | 38
> +++++++++++++++++-------------- drivers/net/wireless/ath/ath5k/base.h |
> 3 +-
> drivers/net/wireless/ath/ath5k/debug.c | 2 +-
> 3 files changed, 24 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath5k/base.c
> b/drivers/net/wireless/ath/ath5k/base.c index 20328bd..b290cc6 100644
> --- a/drivers/net/wireless/ath/ath5k/base.c
> +++ b/drivers/net/wireless/ath/ath5k/base.c
> @@ -388,7 +388,7 @@ static int ath5k_init(struct ath5k_softc *sc);
> static int ath5k_stop_locked(struct ath5k_softc *sc);
> static int ath5k_stop_hw(struct ath5k_softc *sc);
> static irqreturn_t ath5k_intr(int irq, void *dev_id);
> -static void ath5k_tasklet_reset(unsigned long data);
> +static void ath5k_reset_work(struct work_struct *work);
>
> static void ath5k_tasklet_calibrate(unsigned long data);
>
> @@ -831,11 +831,12 @@ ath5k_attach(struct pci_dev *pdev, struct
> ieee80211_hw *hw)
>
> tasklet_init(&sc->rxtq, ath5k_tasklet_rx, (unsigned long)sc);
> tasklet_init(&sc->txtq, ath5k_tasklet_tx, (unsigned long)sc);
> - tasklet_init(&sc->restq, ath5k_tasklet_reset, (unsigned long)sc);
> tasklet_init(&sc->calib, ath5k_tasklet_calibrate, (unsigned long)sc);
> tasklet_init(&sc->beacontq, ath5k_tasklet_beacon, (unsigned long)sc);
> tasklet_init(&sc->ani_tasklet, ath5k_tasklet_ani, (unsigned long)sc);
>
> + INIT_WORK(&sc->reset_work, ath5k_reset_work);
> +
> ret = ath5k_eeprom_read_mac(ah, mac);
> if (ret) {
> ATH5K_ERR(sc, "unable to read address from EEPROM: 0x%04x\n",
> @@ -2294,8 +2295,8 @@ err_unmap:
> * frame contents are done as needed and the slot time is
> * also adjusted based on current state.
> *
> - * This is called from software irq context (beacontq or restq
> - * tasklets) or user context from ath5k_beacon_config.
> + * This is called from software irq context (beacontq tasklets)
> + * or user context from ath5k_beacon_config.
> */
> static void
> ath5k_beacon_send(struct ath5k_softc *sc)
> @@ -2328,7 +2329,7 @@ ath5k_beacon_send(struct ath5k_softc *sc)
> sc->bmisscount);
> ATH5K_DBG(sc, ATH5K_DEBUG_RESET,
> "stuck beacon, resetting\n");
> - tasklet_schedule(&sc->restq);
> + ieee80211_queue_work(sc->hw, &sc->reset_work);
> }
> return;
> }
> @@ -2684,7 +2685,6 @@ ath5k_stop_hw(struct ath5k_softc *sc)
>
> tasklet_kill(&sc->rxtq);
> tasklet_kill(&sc->txtq);
> - tasklet_kill(&sc->restq);
> tasklet_kill(&sc->calib);
> tasklet_kill(&sc->beacontq);
> tasklet_kill(&sc->ani_tasklet);
> @@ -2737,7 +2737,7 @@ ath5k_intr(int irq, void *dev_id)
> */
> ATH5K_DBG(sc, ATH5K_DEBUG_RESET,
> "fatal int, resetting\n");
> - tasklet_schedule(&sc->restq);
> + ieee80211_queue_work(sc->hw, &sc->reset_work);
> } else if (unlikely(status & AR5K_INT_RXORN)) {
> /*
> * Receive buffers are full. Either the bus is busy or
> @@ -2752,7 +2752,7 @@ ath5k_intr(int irq, void *dev_id)
> if (ah->ah_mac_srev < AR5K_SREV_AR5212) {
> ATH5K_DBG(sc, ATH5K_DEBUG_RESET,
> "rx overrun, resetting\n");
> - tasklet_schedule(&sc->restq);
> + ieee80211_queue_work(sc->hw, &sc->reset_work);
> }
> else
> tasklet_schedule(&sc->rxtq);
> @@ -2799,14 +2799,6 @@ ath5k_intr(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> -static void
> -ath5k_tasklet_reset(unsigned long data)
> -{
> - struct ath5k_softc *sc = (void *)data;
> -
> - ath5k_reset(sc, sc->curchan);
> -}
> -
> /*
> * Periodically recalibrate the PHY to account
> * for temperature/environment changes.
> @@ -2830,7 +2822,7 @@ ath5k_tasklet_calibrate(unsigned long data)
> * to load new gain values.
> */
> ATH5K_DBG(sc, ATH5K_DEBUG_RESET, "calibration, resetting\n");
> - ath5k_reset(sc, sc->curchan);
> + ieee80211_queue_work(sc->hw, &sc->reset_work);
> }
> if (ath5k_hw_phy_calibrate(ah, sc->curchan))
> ATH5K_ERR(sc, "calibration of channel %u failed\n",
> @@ -2934,6 +2926,8 @@ drop_packet:
> /*
> * Reset the hardware. If chan is not NULL, then also pause rx/tx
> * and change to the given channel.
> + *
> + * This should be called with sc->lock.
> */
> static int
> ath5k_reset(struct ath5k_softc *sc, struct ieee80211_channel *chan)
> @@ -2990,6 +2984,16 @@ err:
> return ret;
> }
>
> +static void ath5k_reset_work(struct work_struct *work)
> +{
> + struct ath5k_softc *sc = container_of(work, struct ath5k_softc,
> + reset_work);
> +
> + mutex_lock(&sc->lock);
> + ath5k_reset(sc, sc->curchan);
> + mutex_unlock(&sc->lock);
> +}
> +
> static int ath5k_start(struct ieee80211_hw *hw)
> {
> return ath5k_init(hw->priv);
> diff --git a/drivers/net/wireless/ath/ath5k/base.h
> b/drivers/net/wireless/ath/ath5k/base.h index 56221bc..86c90f4 100644
> --- a/drivers/net/wireless/ath/ath5k/base.h
> +++ b/drivers/net/wireless/ath/ath5k/base.h
> @@ -47,6 +47,7 @@
> #include <linux/if_ether.h>
> #include <linux/leds.h>
> #include <linux/rfkill.h>
> +#include <linux/workqueue.h>
>
> #include "ath5k.h"
> #include "debug.h"
> @@ -189,7 +190,7 @@ struct ath5k_softc {
> unsigned int led_pin, /* GPIO pin for driving LED */
> led_on; /* pin setting for LED on */
>
> - struct tasklet_struct restq; /* reset tasklet */
> + struct work_struct reset_work; /* deferred chip reset */
>
> unsigned int rxbufsize; /* rx size based on mtu */
> struct list_head rxbuf; /* receive buffer */
> diff --git a/drivers/net/wireless/ath/ath5k/debug.c
> b/drivers/net/wireless/ath/ath5k/debug.c index 8c63886..ebb9c23 100644
> --- a/drivers/net/wireless/ath/ath5k/debug.c
> +++ b/drivers/net/wireless/ath/ath5k/debug.c
> @@ -279,7 +279,7 @@ static ssize_t write_file_reset(struct file *file,
> {
> struct ath5k_softc *sc = file->private_data;
> ATH5K_DBG(sc, ATH5K_DEBUG_RESET, "debug file triggered reset\n");
> - tasklet_schedule(&sc->restq);
> + ieee80211_queue_work(sc->hw, &sc->reset_work);
> return count;
> }
please get this into 2.6.36...
Acked-by: Bruno Randolf <br1@xxxxxxxxxxx>
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