Re: [stable] [PATCH 1/3] ath9k: Handle -ENOMEM on RX gracefully

[Greg KH <greg@kroah.com>]

I don't see this patch upstream in Linus's tree.  Am I just missing it
and if so, do you know the git commit id?

thanks,

greg k-h


On Tue, Dec 02, 2008 at 12:51:22PM -0800, Luis R. Rodriguez wrote:
> We would get an oops on RX on -ENOMEM by passing
> NULL to the hardware on ath_rx_buf_link(). The oops
> would look something like this:
> 
> ath_rx_tasklet
> ...
> RIP: ath_rx_buf_link
> 
> We correct this by handling the allocation for the next
> skb we will put in our RX tail directly on the ath_rx_tasklet()
> *prior* to sending up the last hardware processed
> skb. If we run out of memory this gauranteees we have
> skbs to work with while it simply drops new received
> frames.
> 
> Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
> ---
>  drivers/net/wireless/ath9k/recv.c |   18 ++++++++++++++----
>  1 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath9k/recv.c b/drivers/net/wireless/ath9k/recv.c
> index 0941589..a4f92b2 100644
> --- a/drivers/net/wireless/ath9k/recv.c
> +++ b/drivers/net/wireless/ath9k/recv.c
> @@ -441,18 +441,16 @@ static void ath_rx_requeue(struct ath_softc *sc, struct sk_buff *skb)
>   */
>  static int ath_rx_indicate(struct ath_softc *sc,
>  			   struct sk_buff *skb,
> +			   struct sk_buff *nskb,
>  			   struct ath_recv_status *status,
>  			   u16 keyix)
>  {
>  	struct ath_buf *bf = ATH_RX_CONTEXT(skb)->ctx_rxbuf;
> -	struct sk_buff *nskb;
>  	int type;
>  
>  	/* indicate frame to the stack, which will free the old skb. */
>  	type = ath__rx_indicate(sc, skb, status, keyix);
>  
> -	/* allocate a new skb and queue it to for H/W processing */
> -	nskb = ath_rxbuf_alloc(sc, sc->sc_rxbufsize);
>  	if (nskb != NULL) {
>  		bf->bf_mpdu = nskb;
>  		bf->bf_buf_addr = ath_skb_map_single(sc,
> @@ -741,6 +739,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
>  	struct ath_desc *ds;
>  	struct ieee80211_hdr *hdr;
>  	struct sk_buff *skb = NULL;
> +	struct sk_buff *nskb = NULL;
>  	struct ath_recv_status rx_status;
>  	struct ath_hal *ah = sc->sc_ah;
>  	int type, rx_processed = 0;
> @@ -963,6 +962,17 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
>  		 */
>  		if (sc->sc_rxbufsize < ds->ds_rxstat.rs_datalen)
>  			goto rx_next;
> +
> +		/* allocate a new skb and queue it to for H/W processing */
> +		nskb = ath_rxbuf_alloc(sc, sc->sc_rxbufsize);
> +
> +		/* Diregard current RX'd frame and reuse the old skb */
> +		if (!nskb) {
> +			list_move_tail(&bf->list, &sc->sc_rxbuf);
> +			ath_rx_buf_link(sc, bf);
> +			goto rx_next;
> +		}
> +
>  		/*
>  		 * Sync and unmap the frame.  At this point we're
>  		 * committed to passing the sk_buff somewhere so
> @@ -1052,7 +1062,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush)
>  
>  		/* Pass frames up to the stack. */
>  
> -		type = ath_rx_indicate(sc, skb,
> +		type = ath_rx_indicate(sc, skb, nskb,
>  			&rx_status, ds->ds_rxstat.rs_keyix);
>  
>  		/*
> -- 
> 1.5.6.rc2.15.g457bb.dirty
> 
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