[dpdk-stable] [dpdk-dev] [PATCH] net/tap: free mempool when closing

[Ferruh Yigit]

On 7/29/2020 12:35 PM, wangyunjian wrote:
> From: Yunjian Wang <wangyunjian at huawei.com>
> 
> When setup tx queues, we will create a mempool for the 'gso_ctx'.
> The mempool is not freed when closing tap device. If free the tap
> device and create it with different name, it will create a new
> mempool. This maybe cause an OOM.
> 
> Fixes: 050316a88313 ("net/tap: support TSO (TCP Segment Offload)")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Yunjian Wang <wangyunjian at huawei.com>

<...>

> @@ -1317,26 +1320,31 @@ tap_gso_ctx_setup(struct rte_gso_ctx *gso_ctx, struct rte_eth_dev *dev)
>  {
>  	uint32_t gso_types;
>  	char pool_name[64];
> -
> -	/*
> -	 * Create private mbuf pool with TAP_GSO_MBUF_SEG_SIZE bytes
> -	 * size per mbuf use this pool for both direct and indirect mbufs
> -	 */
> -
> -	struct rte_mempool *mp;      /* Mempool for GSO packets */
> +	struct pmd_internals *pmd = dev->data->dev_private;
> +	int ret;
>  
>  	/* initialize GSO context */
>  	gso_types = DEV_TX_OFFLOAD_TCP_TSO;
> -	snprintf(pool_name, sizeof(pool_name), "mp_%s", dev->device->name);
> -	mp = rte_mempool_lookup((const char *)pool_name);
> -	if (!mp) {
> -		mp = rte_pktmbuf_pool_create(pool_name, TAP_GSO_MBUFS_NUM,
> -			TAP_GSO_MBUF_CACHE_SIZE, 0,
> +	if (!pmd->gso_ctx_mp) {
> +		/*
> +		 * Create private mbuf pool with TAP_GSO_MBUF_SEG_SIZE
> +		 * bytes size per mbuf use this pool for both direct and
> +		 * indirect mbufs
> +		 */
> +		ret = snprintf(pool_name, sizeof(pool_name), "mp_%s",
> +				dev->device->name);
> +		if (ret < 0 || ret >= (int)sizeof(pool_name)) {
> +			TAP_LOG(ERR,
> +				"%s: failed to create mbuf pool "
> +				"name for device %s\n",
> +				pmd->name, dev->device->name);

Overall looks good. Only above error doesn't say why it failed, informing the
user that device name is too long may help her to overcome the error.