Re: [PATCH v1 3/5] treewide: use get_random_u32() when possible

Jason Gunthorpe
2022-10-06T12:47:49Z

On Wed, Oct 05, 2022 at 11:48:42PM +0200, Jason A. Donenfeld wrote:

> index 14392c942f49..499a425a3379 100644
> --- a/drivers/infiniband/hw/cxgb4/cm.c
> +++ b/drivers/infiniband/hw/cxgb4/cm.c
> @@ -734,7 +734,7 @@ static int send_connect(struct c4iw_ep *ep)
> &ep->com.remote_addr;
> int ret;
> enum chip_type adapter_type = ep->com.dev->rdev.lldi.adapter_type;
> - u32 isn = (prandom_u32() & ~7UL) - 1;
> + u32 isn = (get_random_u32() & ~7UL) - 1;

Maybe this wants to be written as

(prandom_max(U32_MAX >> 7) << 7) | 7

?

> diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
> index fd9d7f2c4d64..a605cf66b83e 100644
> --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
> +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
> @@ -465,7 +465,7 @@ static int ipoib_cm_req_handler(struct ib_cm_id *cm_id,
> goto err_qp;
> }
>
> - psn = prandom_u32() & 0xffffff;
> + psn = get_random_u32() & 0xffffff;

prandom_max(0xffffff + 1)

?

Jason