diff options
| author |   Du Cheng <ducheng2@gmail.com> | 2021-05-03 13:56:46 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-13 17:30:41 +0200 |
| commit | 65a67792e3416f7c5d7daa47d99334cbb19a7449 (patch) | |
| tree | 7bbbcc860533bdb6d48805b1e7fcd89c795d6774 /drivers/net/caif | |
| parent | Revert "net: caif: replace BUG_ON with recovery code" (diff) | |
| download | linux-dev-65a67792e3416f7c5d7daa47d99334cbb19a7449.tar.xz linux-dev-65a67792e3416f7c5d7daa47d99334cbb19a7449.zip | |
net: caif: remove BUG_ON(dev == NULL) in caif_xmit
The condition of dev == NULL is impossible in caif_xmit(), hence it is
for the removal.
Explanation:
The static caif_xmit() is only called upon via a function pointer
`ndo_start_xmit` defined in include/linux/netdevice.h:
```
struct net_device_ops {
...
netdev_tx_t (*ndo_start_xmit)(struct sk_buff *skb, struct net_device *dev);
...
}
```
The exhausive list of call points are:
```
drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
dev->netdev_ops->ndo_start_xmit(skb, dev);
^ ^
drivers/infiniband/ulp/opa_vnic/opa_vnic_netdev.c
struct opa_vnic_adapter *adapter = opa_vnic_priv(netdev);
^ ^
return adapter->rn_ops->ndo_start_xmit(skb, netdev); // adapter would crash first
^ ^
drivers/usb/gadget/function/f_ncm.c
ncm->netdev->netdev_ops->ndo_start_xmit(NULL, ncm->netdev);
^ ^
include/linux/netdevice.h
static inline netdev_tx_t __netdev_start_xmit(...
{
return ops->ndo_start_xmit(skb, dev);
^
}
const struct net_device_ops *ops = dev->netdev_ops;
^
rc = __netdev_start_xmit(ops, skb, dev, more);
^
```
In each of the enumerated scenarios, it is impossible for the NULL-valued dev to
reach the caif_xmit() without crashing the kernel earlier, therefore `BUG_ON(dev ==
NULL)` is rather useless, hence the removal.
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Du Cheng <ducheng2@gmail.com>
Link: https://lore.kernel.org/r/20210503115736.2104747-20-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net/caif')
| -rw-r--r-- | drivers/net/caif/caif_serial.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/net/caif/caif_serial.c b/drivers/net/caif/caif_serial.c index a7f51eb58915..d17482395a4d 100644 --- a/drivers/net/caif/caif_serial.c +++ b/drivers/net/caif/caif_serial.c @@ -269,7 +269,6 @@ static netdev_tx_t caif_xmit(struct sk_buff *skb, struct net_device *dev) { struct ser_device *ser; - BUG_ON(dev == NULL); ser = netdev_priv(dev); /* Send flow off once, on high water mark */ |