diff mbox

[1/2] mwifiex: resubmit failed to submit RX URBs in main thread

Message ID 1504122674-3379-2-git-send-email-gbhat@marvell.com (mailing list archive)
State Changes Requested
Delegated to: Kalle Valo
Headers show

Commit Message

Ganapathi Bhat Aug. 30, 2017, 7:51 p.m. UTC
From: James Cao <jcao@marvell.com>

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 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@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Ganapathi Bhat <gbhat@marvell.com>
---
 drivers/net/wireless/marvell/mwifiex/main.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Comments

Kalle Valo Sept. 20, 2017, 12:13 p.m. UTC | #1
Ganapathi Bhat <gbhat@marvell.com> writes:

> From: James Cao <jcao@marvell.com>
>
> 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@marvell.com>
> Signed-off-by: Cathy Luo <cluo@marvell.com>
> Signed-off-by: Ganapathi Bhat <gbhat@marvell.com>

[...]

> @@ -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.
diff mbox

Patch

diff --git a/drivers/net/wireless/marvell/mwifiex/main.c b/drivers/net/wireless/marvell/mwifiex/main.c
index ee40b73..c78014b 100644
--- a/drivers/net/wireless/marvell/mwifiex/main.c
+++ b/drivers/net/wireless/marvell/mwifiex/main.c
@@ -247,6 +247,7 @@  int mwifiex_main_process(struct mwifiex_adapter *adapter)
 {
 	int ret = 0;
 	unsigned long flags;
+	struct usb_card_rec *usb_card;
 
 	spin_lock_irqsave(&adapter->main_proc_lock, flags);
 
@@ -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);
+		}
+
 		/* Handle pending interrupt if any */
 		if (adapter->int_status) {
 			if (adapter->hs_activated)