[PATCH 5.16 1015/1039] net: wwan: Fix MRU mismatch issue which may lead to data connection lost

From: Greg Kroah-Hartman
Date: Mon Jan 24 2022 - 21:01:02 EST


From: Slark Xiao <slark_xiao@xxxxxxx>

commit f542cdfa3083a309e3caafbbdf41490c4935492a upstream.

In pci_generic.c there is a 'mru_default' in struct mhi_pci_dev_info.
This value shall be used for whole mhi if it's given a value for a specific product.
But in function mhi_net_rx_refill_work(), it's still using hard code value MHI_DEFAULT_MRU.
'mru_default' shall have higher priority than MHI_DEFAULT_MRU.
And after checking, this change could help fix a data connection lost issue.

Fixes: 5c2c85315948 ("bus: mhi: pci-generic: configurable network interface MRU")
Signed-off-by: Shujun Wang <wsj20369@xxxxxxx>
Signed-off-by: Slark Xiao <slark_xiao@xxxxxxx>
Reviewed-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/wwan/mhi_wwan_mbim.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/wwan/mhi_wwan_mbim.c
+++ b/drivers/net/wwan/mhi_wwan_mbim.c
@@ -385,13 +385,13 @@ static void mhi_net_rx_refill_work(struc
int err;

while (!mhi_queue_is_full(mdev, DMA_FROM_DEVICE)) {
- struct sk_buff *skb = alloc_skb(MHI_DEFAULT_MRU, GFP_KERNEL);
+ struct sk_buff *skb = alloc_skb(mbim->mru, GFP_KERNEL);

if (unlikely(!skb))
break;

err = mhi_queue_skb(mdev, DMA_FROM_DEVICE, skb,
- MHI_DEFAULT_MRU, MHI_EOT);
+ mbim->mru, MHI_EOT);
if (unlikely(err)) {
kfree_skb(skb);
break;