RE: [PATCH rdma-next 1/1] RDMA/mana_ib: Fix integer overflow during queue creation

[Long Li]

> Subject: [PATCH rdma-next 1/1] RDMA/mana_ib: Fix integer overflow during
> queue creation
> 
> From: Konstantin Taranov <kotaranov@xxxxxxxxxxxxx>
> 
> Use size_t instead of u32 in helpers for queue creations to detect overflow of
> queue size. The queue size cannot exceed size of u32.
> 
> Fixes: bd4ee700870a ("RDMA/mana_ib: UD/GSI QP creation for kernel")
> Signed-off-by: Konstantin Taranov <kotaranov@xxxxxxxxxxxxx>
> ---
>  drivers/infiniband/hw/mana/cq.c      |  9 +++++----
>  drivers/infiniband/hw/mana/main.c    | 15 +++++++++++++--
>  drivers/infiniband/hw/mana/mana_ib.h |  4 ++--
>  drivers/infiniband/hw/mana/qp.c      | 11 ++++++-----
>  4 files changed, 26 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/mana/cq.c b/drivers/infiniband/hw/mana/cq.c
> index 5c325ef..07b97da 100644
> --- a/drivers/infiniband/hw/mana/cq.c
> +++ b/drivers/infiniband/hw/mana/cq.c
> @@ -18,7 +18,7 @@ int mana_ib_create_cq(struct ib_cq *ibcq, const struct
> ib_cq_init_attr *attr,
>  	struct gdma_context *gc;
>  	bool is_rnic_cq;
>  	u32 doorbell;
> -	u32 buf_size;
> +	size_t buf_size;
>  	int err;
> 
>  	mdev = container_of(ibdev, struct mana_ib_dev, ib_dev); @@ -45,7
> +45,8 @@ int mana_ib_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr
> *attr,
>  		}
> 
>  		cq->cqe = attr->cqe;
> -		err = mana_ib_create_queue(mdev, ucmd.buf_addr, cq->cqe *
> COMP_ENTRY_SIZE,
> +		buf_size = (size_t)cq->cqe * COMP_ENTRY_SIZE;
> +		err = mana_ib_create_queue(mdev, ucmd.buf_addr, buf_size,
>  					   &cq->queue);
>  		if (err) {
>  			ibdev_dbg(ibdev, "Failed to create queue for create
> cq, %d\n", err); @@ -57,8 +58,8 @@ int mana_ib_create_cq(struct ib_cq *ibcq,
> const struct ib_cq_init_attr *attr,
>  		doorbell = mana_ucontext->doorbell;
>  	} else {
>  		is_rnic_cq = true;
> -		buf_size = MANA_PAGE_ALIGN(roundup_pow_of_two(attr->cqe
> * COMP_ENTRY_SIZE));
> -		cq->cqe = buf_size / COMP_ENTRY_SIZE;
> +		cq->cqe = attr->cqe;
> +		buf_size =
> MANA_PAGE_ALIGN(roundup_pow_of_two((size_t)attr->cqe *
> +COMP_ENTRY_SIZE));

Why not do a check like:
If (attr->cqe > U32_MAX/COMP_ENTRY_SIZE)
	return -EINVAL;

And you don't need to check them in mana_ib_create_kernel_queue() and mana_ib_create_queue().