Subject: Re: [PATCH rdma-next v6] RDMA: Change capability fields in ib_device_attr from int to u32

From: David Laight <[email-masked]>
Date: Tue, 2 Jun 2026 12:33:27 +0100

On Mon,  1 Jun 2026 02:25:15 -0700
Erni Sri Satya Vennela <[email-masked]> wrote:

> The capability counter fields in struct ib_device_attr are declared
> as signed int, but these values are inherently non-negative. Drivers
> maintain their cached caps as u32 and assign them directly into these
> int fields; if a cap exceeds INT_MAX the implicit narrowing yields a
> negative value visible to the IB core.
> 
> Change the signed int capability fields to u32 to match the
> underlying nature of the data. Also update consumers across the IB
> core, ULPs, NVMe-oF target, RDS, and NFS/RDMA so the new u32 values
> are not forced back through signed int or u8 via min()/min_t() or
> narrowing local variables.
> 
> Suggested-by: Jason Gunthorpe <[email-masked]>
> Signed-off-by: Erni Sri Satya Vennela <[email-masked]>
> ---
...
> diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c
> index 6482ad859bd1..852213365ecd 100644
> --- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c
> +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c
> @@ -1731,7 +1731,7 @@ static int create_con(struct rtrs_srv_path *srv_path,
>  		 * All receive and all send (each requiring invalidate)
>  		 * + 2 for drain and heartbeat
>  		 */
> -		max_send_wr = min_t(int, wr_limit,
> +		max_send_wr = min_t(u32, wr_limit,
>  				    SERVICE_CON_QUEUE_DEPTH * 2 + 2);

That should compile as min().
(The constant is known to be non-negative.)

...
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index e6e2c3f9afdf..fd6923198ec1 100644
> --- a/drivers/nvme/target/rdma.c
> +++ b/drivers/nvme/target/rdma.c
...
> @@ -1553,8 +1554,8 @@ static int nvmet_rdma_cm_accept(struct rdma_cm_id *cm_id,
>  
>  	param.rnr_retry_count = 7;
>  	param.flow_control = 1;
> -	param.initiator_depth = min_t(u8, p->initiator_depth,
> -		queue->dev->device->attrs.max_qp_init_rd_atom);
> +	param.initiator_depth = (u8)min_t(u32, p->initiator_depth,
> +		min_t(u32, U8_MAX, queue->dev->device->attrs.max_qp_init_rd_atom));

I think you've change one of those to min_3().
Nesting min() is a good way to bloat the pre-processor output.
You don't need any of the casts.
	
	param.initiator_depth = min_3(p->initiator_depth,
		queue->dev->device->attrs.max_qp_init_rd_atom, U8_MAX);
should be fine - if a bit long.

There are also (u32)U8_MAX casts lurking - pointless.

-- David