Re: [dpdk-dev] [PATCH] ethdev: add size and align to compose dma zone name strings

[David Marchand <david.marchand@redhat.com>]

On Sat, Apr 27, 2019 at 11:48 AM wangyunjian <wangyunjian@huawei.com> wrote:

> From: Yunjian Wang <wangyunjian@huawei.com>
>
> The current dma zone name consists of the port_id, queue_id and
> ring_name. If a port_id is reused, a new nic maybe use same dma
> zone name. At this time, the zone size of the new driver is
> differnt. When the zone is reused, it may cause illegal access
> to memory.
>
> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> ---
>  lib/librte_ethdev/rte_ethdev.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/lib/librte_ethdev/rte_ethdev.c
> b/lib/librte_ethdev/rte_ethdev.c
> index d7cfa3d..0703cda 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -3630,9 +3630,9 @@ int rte_eth_set_queue_rate_limit(uint16_t port_id,
> uint16_t queue_idx,
>         const struct rte_memzone *mz;
>         int rc;
>
> -       rc = snprintf(z_name, sizeof(z_name), "eth_p%d_q%d_%s",
> -                     dev->data->port_id, queue_id, ring_name);
> -       if (rc >= RTE_MEMZONE_NAMESIZE) {
> +       rc = snprintf(z_name, sizeof(z_name), "p%dq%d%s0x%zx_%d",
> +                     dev->data->port_id, queue_id, ring_name, size,
> align);
> +       if (rc >= RTE_MEMZONE_NAMESIZE || rc < 0) {
>                 RTE_ETHDEV_LOG(ERR, "ring name too long\n");
>                 rte_errno = ENAMETOOLONG;
>                 return NULL;
>

In such a case, we are leaving the previous memzone in place and just
creating a new one.
Should the driver free the previous memzone instead?

I can't see this in existing drivers.
Do we actually expect to reuse the existing memzones?


-- 
David Marchand