Re: [PATCH] IB/core: type promotion bug in rdma_rw_init_one_mr()

Walter Harms
2018-07-04T10:41:53Z

Am 04.07.2018 11:32, schrieb Dan Carpenter:
> "nents" is an unsigned int, so if ib_map_mr_sg() returns a negative
> error code then it's type promoted to a high unsigned int which is
> treated as success.
>
> Fixes: a060b5629ab0 ("IB/core: generic RDMA READ/WRITE API")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/drivers/infiniband/core/rw.c b/drivers/infiniband/core/rw.c
> index c8963e91f92a..3ee0adfb45e9 100644
> --- a/drivers/infiniband/core/rw.c
> +++ b/drivers/infiniband/core/rw.c
> @@ -87,7 +87,7 @@ static int rdma_rw_init_one_mr(struct ib_qp *qp, u8
> port_num,
> }
>
> ret = ib_map_mr_sg(reg->mr, sg, nents, &offset, PAGE_SIZE);
> - if (ret < nents) {
> + if (ret < 0 || ret < nents) {
> ib_mr_pool_put(qp, &qp->rdma_mrs, reg->mr);
> return -EINVAL;
> }

I do not understand the error here.

ib_map_mr_sg() obviously knows about nents and returns an invalid value ?
Or is that a special case here ?

re,
wh

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