Re: [PATCH net-next v4 1/3] net: devmem: allow rx-buf-size > PAGE_SIZE per dmabuf binding

[Paolo Abeni <pabeni@redhat.com>]

On 7/7/26 10:36 PM, Mina Almasry wrote:
> On Wed, Jul 1, 2026 at 12:22 PM Bobby Eshleman <bobbyeshleman@gmail.com> wrote:
>>
>> From: Bobby Eshleman <bobbyeshleman@meta.com>
>>
>> Every devmem dmabuf binding today hands the page_pool PAGE_SIZE niovs.
>> This caps a single RX descriptor at PAGE_SIZE, burning CPU on buffer
>> churn for large flows.
>>
>> Add a bind-time netlink attribute, NETDEV_A_DMABUF_RX_BUF_SIZE, that
>> lets userspace request a larger niov size. The value must be a power of
>> two >= PAGE_SIZE.
>>
>> Measurements
>> ------------

Checkpatch complains about this separator usage:

ERROR: Invalid commit separator - some tools may have problems applying this
#15:
------------

Please replace or remove it in the next revision

>> @@ -90,16 +90,17 @@ net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding)
>>         struct dmabuf_genpool_chunk_owner *owner;
>>         unsigned long dma_addr;
>>         struct net_iov *niov;
>> -       ssize_t offset;
>> -       ssize_t index;
>> +       size_t offset;
>> +       size_t index;
>>
> 
> nit: I would keep this signed. Some of the most frustrating issues I
> ran into is some of the underflowing and then passing a > check or
> something. Although if the LLM is not complaining about this
> particular case, there is probably no issue with it. I also notice a
> lot of existing code that deals with indexes and offsets goes for
> signed.

At very least the above change should go in a separate patch, as is
quite unrelated from the rest.

/P