[dpdk-dev] [PATCH] ethdev: add size and align to compose dma zone name strings
Andrew Rybchenko
arybchenko at solarflare.com
Wed May 8 15:52:22 CEST 2019
On 4/29/19 11:03 AM, David Marchand wrote:
> On Sat, Apr 27, 2019 at 11:48 AM wangyunjian <wangyunjian at huawei.com
> <mailto:wangyunjian at huawei.com>> wrote:
>
> From: Yunjian Wang <wangyunjian at huawei.com
> <mailto:wangyunjian at 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 at huawei.com
> <mailto:wangyunjian at 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?
>
I don't think the patch is a right way to go.
It is related to [1] which has a long discussion.
Andrew.
[1] https://patches.dpdk.org/patch/51952/
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