Re: [PATCH] ath5k: Invoke irqsafe version of ieee80211_tx_status() to avoid deadlock

["John W. Linville" <linville@tuxdriver.com>]

On Wed, Aug 24, 2011 at 06:34:24PM -0700, Thomas Pedersen wrote:
> From: Javier Cardona <javier@cozybit.com>
> 
> This driver reports transmission status to the upper layer
> (ath5k_tx_frame_completed()) while holding the lock on the transmission
> queue (txq->lock).  Under failure conditions, the mesh stack will
> attempt to send PERR messages to the previous sender of the failed
> frame.  When that happens the driver will attempt to re-acquire the
> txq->lock lock causing a deadlock.  There are two possible fixes for
> this, (1) we could defer the transmission of the PERR frame until the
> lock is released or (2) release the lock before invoking
> ieee80211_tx_status().  The ath9k driver implements the second approach
> (see ath_tx_complete() in ath9k/xmit.c) as well as the rt2x00 and b43
> drivers.  The iwl driver, on the other hand, avoids this problem by
> invoking  ieee80211_tx_status_irqsafe() which effectively defers
> processing of transmission feedback status.  This last approach is the
> least intrusive is implemented here.
> 
> Reported by Pedro Larbig (ASPj)
> ---
>  drivers/net/wireless/ath/ath5k/base.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

Missing Signed-off-by...

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John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.