Re: [PATCH 1/5] rust: core abstractions for network device drivers

[FUJITA Tomonori <fujita.tomonori@gmail.com>]

Hi,

On Wed, 21 Jun 2023 15:44:42 -0700
Boqun Feng <boqun.feng@gmail.com> wrote:

> On Tue, Jun 13, 2023 at 01:53:22PM +0900, FUJITA Tomonori wrote:
>> +impl<D: DriverData, T: DeviceOperations<D>> Registration<T, D> {
>> +    /// Creates a new [`Registration`] instance for ethernet device.
>> +    ///
>> +    /// A device driver can pass private data.
>> +    pub fn try_new_ether(tx_queue_size: u32, rx_queue_size: u32, data: D::Data) -> Result<Self> {
>> +        // SAFETY: FFI call.
>> +        let ptr = from_err_ptr(unsafe {
>> +            bindings::alloc_etherdev_mqs(
>> +                core::mem::size_of::<*const c_void>() as i32,
>> +                tx_queue_size,
>> +                rx_queue_size,
>> +            )
>> +        })?;
>> +
>> +        // SAFETY: `ptr` is valid and non-null since `alloc_etherdev_mqs()`
>> +        // returned a valid pointer which was null-checked.
> 
> Hmm.. neither alloc_etherdev_mqs() nor `from_err_ptr` would do the
> null-check IIUC, so you may get a `ptr` whose values is null here.

Oops, `ptr.is_null()` should be used here instead.

Thanks a lot!