Re: [PATCH 1/2] mwifiex: resubmit failed to submit RX URBs in main thread
From: Kalle Valo <hidden>
Date: 2017-09-20 12:13:10
Ganapathi Bhat [off-list ref] writes:
From: James Cao <redacted> 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 <redacted> Signed-off-by: Cathy Luo <redacted> Signed-off-by: Ganapathi Bhat <redacted>
[...]
quoted hunk ↗ jump to hunk
@@ -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