Re: [PATCH v3] vdpa/sfc: make MCDI memzone name unique

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 2/14/22 11:51, abhimanyu.saini@xilinx.com wrote:
> From: Abhimanyu Saini <asaini@xilinx.com>
> 
> Buffer for MCDI channel is allocated using rte_memzone_reserve_aligned
> with zone name 'mcdi'. Since multiple MCDI channels are needed to
> support multiple VF(s) and rte_memzone_reserve_aligned expects unique
> zone names, append PCI address to zone name to make it unique.
> 
> Signed-off-by: Abhimanyu Saini <asaini@xilinx.com>
> ---
> v2:
>    - Formatting changes
> v3:
>    - Formatting changes
> 
>   drivers/vdpa/sfc/sfc_vdpa_hw.c | 15 ++++++++++++---
>   1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/vdpa/sfc/sfc_vdpa_hw.c b/drivers/vdpa/sfc/sfc_vdpa_hw.c
> index fd1fee7..a7018b1 100644
> --- a/drivers/vdpa/sfc/sfc_vdpa_hw.c
> +++ b/drivers/vdpa/sfc/sfc_vdpa_hw.c
> @@ -25,21 +25,30 @@
>   {
>   	uint64_t mcdi_iova;
>   	size_t mcdi_buff_size;
> +	char mz_name[RTE_MEMZONE_NAMESIZE];
>   	const struct rte_memzone *mz = NULL;
>   	int numa_node = sva->pdev->device.numa_node;
>   	int ret;
>   
>   	mcdi_buff_size = RTE_ALIGN_CEIL(len, PAGE_SIZE);
> +	ret = snprintf(mz_name, RTE_MEMZONE_NAMESIZE, "%s_%s",
> +		       sva->pdev->name, name);
> +	if (ret < 0 || ret >= RTE_MEMZONE_NAMESIZE) {

 From the man page:
"
The functions snprintf() and vsnprintf() do not write more than size 
bytes (including the terminating null byte ('\0')).
"

you might want to pass RTE_MEMZONE_NAMESIZE - 1 as size arg to snprintf,
so you can just check ret >= 0?

> +		sfc_vdpa_err(sva, "%s_%s too long to fit in mz_name",
> +			     sva->pdev->name, name);
> +		return -EINVAL;
> +	}
>   
> -	sfc_vdpa_log_init(sva, "name=%s, len=%zu", name, len);
> +	sfc_vdpa_log_init(sva, "name=%s, len=%zu", mz_name, len);
>   
> -	mz = rte_memzone_reserve_aligned(name, mcdi_buff_size,
> +	mz = rte_memzone_reserve_aligned(mz_name, mcdi_buff_size,
>   					 numa_node,
>   					 RTE_MEMZONE_IOVA_CONTIG,
>   					 PAGE_SIZE);
>   	if (mz == NULL) {
>   		sfc_vdpa_err(sva, "cannot reserve memory for %s: len=%#x: %s",
> -			     name, (unsigned int)len, rte_strerror(rte_errno));
> +			     mz_name, (unsigned int)len,
> +			     rte_strerror(rte_errno));
>   		return -ENOMEM;
>   	}
>