2010/4/6 Sujith <Sujith.Manoharan@xxxxxxxxxxx>:
> Use a spin lock to prevent concurrent access
> to variables dealing with RX stream mode handling.
which variables are needed to be protected?
It seems hif_dev->rx_transfer_len, hif_dev->remain_skb
and hif_dev->rx_pkt_len are only accessed in ath9k_hif_usb_rx_stream,
which is only called in hard irq(urb->complete) context and now is
serialized strictly, so the protection is useless, isn't it?
> Currently, no protection is implemented - which
> causes problems in RX.
which problems? Could you describe them in detail?
Thanks,
>
> Signed-off-by: Sujith <Sujith.Manoharan@xxxxxxxxxxx>
> ---
> drivers/net/wireless/ath/ath9k/hif_usb.c | 8 ++++++++
> drivers/net/wireless/ath/ath9k/hif_usb.h | 1 +
> 2 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
> index 3afc747..8838cdf 100644
> --- a/drivers/net/wireless/ath/ath9k/hif_usb.c
> +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
> @@ -330,6 +330,8 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
> u16 pkt_len, pkt_tag, pool_index = 0;
> u8 *ptr;
>
> + spin_lock(&hif_dev->rx_lock);
> +
> rx_remain_len = hif_dev->rx_remain_len;
> rx_pkt_len = hif_dev->rx_transfer_len;
>
> @@ -356,6 +358,8 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
> }
> }
>
> + spin_unlock(&hif_dev->rx_lock);
> +
> while (index < len) {
> ptr = (u8 *) skb->data;
>
> @@ -373,6 +377,7 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
> index = index + 4 + pkt_len + pad_len;
>
> if (index > MAX_RX_BUF_SIZE) {
> + spin_lock(&hif_dev->rx_lock);
> hif_dev->rx_remain_len = index - MAX_RX_BUF_SIZE;
> hif_dev->rx_transfer_len =
> MAX_RX_BUF_SIZE - chk_idx - 4;
> @@ -384,6 +389,7 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
> dev_err(&hif_dev->udev->dev,
> "ath9k_htc: RX memory allocation"
> " error\n");
> + spin_unlock(&hif_dev->rx_lock);
> goto err;
> }
> skb_reserve(nskb, 32);
> @@ -394,6 +400,7 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
>
> /* Record the buffer pointer */
> hif_dev->remain_skb = nskb;
> + spin_unlock(&hif_dev->rx_lock);
> } else {
> nskb = __dev_alloc_skb(pkt_len + 32, GFP_ATOMIC);
> if (!nskb) {
> @@ -612,6 +619,7 @@ static int ath9k_hif_usb_alloc_rx_urbs(struct hif_device_usb *hif_dev)
> int i, ret;
>
> init_usb_anchor(&hif_dev->rx_submitted);
> + spin_lock_init(&hif_dev->rx_lock);
>
> for (i = 0; i < MAX_RX_URB_NUM; i++) {
>
> diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.h b/drivers/net/wireless/ath/ath9k/hif_usb.h
> index ea9257b..ed9708c 100644
> --- a/drivers/net/wireless/ath/ath9k/hif_usb.h
> +++ b/drivers/net/wireless/ath/ath9k/hif_usb.h
> @@ -93,6 +93,7 @@ struct hif_device_usb {
> int rx_pkt_len;
> int rx_transfer_len;
> int rx_pad_len;
> + spinlock_t rx_lock;
> u8 flags; /* HIF_USB_* */
> };
>
> --
> 1.7.0.3
>
> --
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--
Lei Ming
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