Ganapathi Bhat <gbhat@xxxxxxxxxxx> writes:
> From: James Cao <jcao@xxxxxxxxxxx>
>
> Current driver has 6 Rx data URBs. Once any packet received
> kernel calls our callback, in which the same URB will be
> resubmitted after Rx indication. In URB submission function a new
> skb will be allocated since the previous one is passed to upper
> layer (freed later). Since the skb is from a special pool (not
> regular memory), skb allocation may fail when kernel holds a lot
> of Rx packets on some low resource platforms.
The special pool being GFP_ATOMIC allocations or what?
> The URB will not be resubmitted in this no free skb case. If driver
> fails to resubmit all 6 URBs, Rx will stop. To cover this scenario
> check and resubmit Rx URBs in main thread.
>
> Signed-off-by: James Cao <jcao@xxxxxxxxxxx>
> Signed-off-by: Cathy Luo <cluo@xxxxxxxxxxx>
> Signed-off-by: Ganapathi Bhat <gbhat@xxxxxxxxxxx>
[...]
> @@ -278,6 +279,16 @@ int mwifiex_main_process(struct mwifiex_adapter *adapter)
> break;
> }
>
> + /* Try to resubmit RX URB if sunmission failed earlier */
> + if (!atomic_read(&adapter->rx_pending) &&
> + adapter->iface_type == MWIFIEX_USB) {
> + usb_card = adapter->card;
> + if (atomic_read(&usb_card->rx_data_urb_pending) <
> + MWIFIEX_RX_DATA_URB &&
> + adapter->if_ops.submit_rem_rx_urbs)
> + adapter->if_ops.submit_rem_rx_urbs(adapter);
> + }
To me this just feels wrong. Normally the proceduce is to drop the frame
if allocations fail, not try to reallocate. I need more convincing that
this really is the right approach.
--
Kalle Valo
