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Date: Mon, 5 Oct 2009 14:29:57 -0700
From: "Michael Chan" <mchan@...adcom.com>
To: "Matt Carlson" <mcarlson@...adcom.com>
cc: "Felix Radensky" <felix@...edded-sol.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"andy@...yhouse.net" <andy@...yhouse.net>
Subject: Re: [PATCH net-2.6] tg3: Fix phylib locking strategy
On Mon, 2009-10-05 at 14:09 -0700, Matt Carlson wrote:
> Felix, can you verify this solves your problem?
>
> ---
>
> Felix Radensky noted that chip resets were generating stack trace dumps.
> This is because the driver is attempting to acquire the mdio bus mutex
> while holding the tp->lock spinlock. The fix is to change the code such
> that every phy access takes the tp->lock spinlock instead.
>
> Signed-off-by: Matt Carlson <mcarlson@...adcom.com>
> ---
> drivers/net/tg3.c | 37 ++++++++++++-------------------------
> drivers/net/tg3.h | 1 -
> 2 files changed, 12 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
> index f09bc5d..8afc60e 100644
> --- a/drivers/net/tg3.c
> +++ b/drivers/net/tg3.c
> @@ -902,11 +902,12 @@ static int tg3_mdio_read(struct mii_bus *bp, int mii_id, int reg)
> struct tg3 *tp = bp->priv;
> u32 val;
>
> - if (tp->tg3_flags3 & TG3_FLG3_MDIOBUS_PAUSED)
> - return -EAGAIN;
> + spin_lock(&tp->lock);
>
Matt, do we need spin_lock_bh() here? The tp->lock can be taken in NAPI
poll BH context.
> if (tg3_readphy(tp, reg, &val))
> - return -EIO;
> + val = -EIO;
> +
> + spin_unlock(&tp->lock);
>
> return val;
> }
> @@ -914,14 +915,16 @@ static int tg3_mdio_read(struct mii_bus *bp, int mii_id, int reg)
> static int tg3_mdio_write(struct mii_bus *bp, int mii_id, int reg, u16 val)
> {
> struct tg3 *tp = bp->priv;
> + u32 ret = 0;
>
> - if (tp->tg3_flags3 & TG3_FLG3_MDIOBUS_PAUSED)
> - return -EAGAIN;
> + spin_lock(&tp->lock);
>
> if (tg3_writephy(tp, reg, val))
> - return -EIO;
> + ret = -EIO;
>
> - return 0;
> + spin_unlock(&tp->lock);
> +
> + return ret;
> }
>
> static int tg3_mdio_reset(struct mii_bus *bp)
> @@ -1011,12 +1014,6 @@ static void tg3_mdio_config_5785(struct tg3 *tp)
>
> static void tg3_mdio_start(struct tg3 *tp)
> {
> - if (tp->tg3_flags3 & TG3_FLG3_MDIOBUS_INITED) {
> - mutex_lock(&tp->mdio_bus->mdio_lock);
> - tp->tg3_flags3 &= ~TG3_FLG3_MDIOBUS_PAUSED;
> - mutex_unlock(&tp->mdio_bus->mdio_lock);
> - }
> -
> tp->mi_mode &= ~MAC_MI_MODE_AUTO_POLL;
> tw32_f(MAC_MI_MODE, tp->mi_mode);
> udelay(80);
> @@ -1041,15 +1038,6 @@ static void tg3_mdio_start(struct tg3 *tp)
> tg3_mdio_config_5785(tp);
> }
>
> -static void tg3_mdio_stop(struct tg3 *tp)
> -{
> - if (tp->tg3_flags3 & TG3_FLG3_MDIOBUS_INITED) {
> - mutex_lock(&tp->mdio_bus->mdio_lock);
> - tp->tg3_flags3 |= TG3_FLG3_MDIOBUS_PAUSED;
> - mutex_unlock(&tp->mdio_bus->mdio_lock);
> - }
> -}
> -
> static int tg3_mdio_init(struct tg3 *tp)
> {
> int i;
> @@ -1141,7 +1129,6 @@ static void tg3_mdio_fini(struct tg3 *tp)
> tp->tg3_flags3 &= ~TG3_FLG3_MDIOBUS_INITED;
> mdiobus_unregister(tp->mdio_bus);
> mdiobus_free(tp->mdio_bus);
> - tp->tg3_flags3 &= ~TG3_FLG3_MDIOBUS_PAUSED;
> }
> }
>
> @@ -6392,8 +6379,6 @@ static int tg3_chip_reset(struct tg3 *tp)
>
> tg3_nvram_lock(tp);
>
> - tg3_mdio_stop(tp);
> -
> tg3_ape_lock(tp, TG3_APE_LOCK_GRC);
>
> /* No matching tg3_nvram_unlock() after this because
> @@ -8698,6 +8683,8 @@ static int tg3_close(struct net_device *dev)
>
> del_timer_sync(&tp->timer);
>
> + tg3_phy_stop(tp);
> +
> tg3_full_lock(tp, 1);
> #if 0
> tg3_dump_state(tp);
> diff --git a/drivers/net/tg3.h b/drivers/net/tg3.h
> index 524691c..bab7940 100644
> --- a/drivers/net/tg3.h
> +++ b/drivers/net/tg3.h
> @@ -2748,7 +2748,6 @@ struct tg3 {
> #define TG3_FLG3_5701_DMA_BUG 0x00000008
> #define TG3_FLG3_USE_PHYLIB 0x00000010
> #define TG3_FLG3_MDIOBUS_INITED 0x00000020
> -#define TG3_FLG3_MDIOBUS_PAUSED 0x00000040
> #define TG3_FLG3_PHY_CONNECTED 0x00000080
> #define TG3_FLG3_RGMII_STD_IBND_DISABLE 0x00000100
> #define TG3_FLG3_RGMII_EXT_IBND_RX_EN 0x00000200
--
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