Re: [net-next Patch v8 5/6] octeontx2-pf: Add support for HTB offload

[Simon Horman <simon.horman@corigine.com>]

On Mon, Apr 10, 2023 at 02:12:22PM +0530, Hariprasad Kelam wrote:
> From: Naveen Mamindlapalli <naveenm@marvell.com>
> 
> This patch registers callbacks to support HTB offload.
> 
> Below are features supported,
> 
> - supports traffic shaping on the given class by honoring rate and ceil
> configuration.
> 
> - supports traffic scheduling,  which prioritizes different types of
> traffic based on strict priority values.
> 
> - supports the creation of leaf to inner classes such that parent node
> rate limits apply to all child nodes.
> 
> Signed-off-by: Naveen Mamindlapalli <naveenm@marvell.com>
> Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
> Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
> Reviewed-by: Simon Horman <simon.horman@corigine.com>

...

> +static int otx2_qos_txschq_alloc(struct otx2_nic *pfvf,
> +				 struct otx2_qos_cfg *cfg)
> +{
> +	struct nix_txsch_alloc_req *req;
> +	struct nix_txsch_alloc_rsp *rsp;
> +	struct mbox *mbox = &pfvf->mbox;
> +	int lvl, rc, schq;
> +
> +	mutex_lock(&mbox->lock);
> +	req = otx2_mbox_alloc_msg_nix_txsch_alloc(&pfvf->mbox);
> +	if (!req) {
> +		mutex_unlock(&mbox->lock);
> +		return -ENOMEM;
> +	}
> +
> +	for (lvl = 0; lvl < NIX_TXSCH_LVL_CNT; lvl++) {
> +		req->schq[lvl] = cfg->schq[lvl];
> +		req->schq_contig[lvl] = cfg->schq_contig[lvl];
> +	}
> +
> +	rc = otx2_sync_mbox_msg(&pfvf->mbox);
> +	if (rc) {
> +		mutex_unlock(&mbox->lock);
> +		return rc;
> +	}
> +
> +	rsp = (struct nix_txsch_alloc_rsp *)
> +	      otx2_mbox_get_rsp(&pfvf->mbox.mbox, 0, &req->hdr);

I think you need to check if otx2_mbox_get_rsp returned an error here.

Smatch reported this as:

drivers/net/ethernet/marvell/octeontx2/nic/qos.c:719 otx2_qos_txschq_alloc() error: 'rsp' dereferencing possible ERR_PTR()


> +
> +	for (lvl = 0; lvl < NIX_TXSCH_LVL_CNT; lvl++) {
> +		for (schq = 0; schq < rsp->schq_contig[lvl]; schq++) {
> +			cfg->schq_contig_list[lvl][schq] =
> +				rsp->schq_contig_list[lvl][schq];
> +		}
> +	}