Subject: Re: [PATCH v2 12/30] cxlflash: Refine host/device attributes

From: Brian King <[email-masked]>
Date: Fri, 18 Sep 2015 16:34:41 -0500

On 09/16/2015 04:29 PM, Matthew R. Ochs wrote:
> Implement the following suggestions and add two new attributes
> to allow for debugging the port LUN table.
> 
>  - use scnprintf() instead of snprintf()
>  - use DEVICE_ATTR_RO and DEVICE_ATTR_RW
> 
> Signed-off-by: Matthew R. Ochs <[email-masked]>
> Signed-off-by: Manoj N. Kumar <[email-masked]>
> Suggested-by: Shane Seymour <[email-masked]>
> ---
>  drivers/scsi/cxlflash/main.c | 180 +++++++++++++++++++++++++++++++++----------
>  1 file changed, 138 insertions(+), 42 deletions(-)
> 

>  /**
> - * cxlflash_show_dev_mode() - presents the current mode of the device
> + * cxlflash_show_port_lun_table() - queries and presents the port LUN table
> + * @port:	Desired port for status reporting.
> + * @afu:	AFU owning the specified port.
> + * @buf:	Buffer of length PAGE_SIZE to report back port status in ASCII.
> + *
> + * Return: The size of the ASCII string returned in @buf.
> + */
> +static ssize_t cxlflash_show_port_lun_table(u32 port,
> +					    struct afu *afu,
> +					    char *buf)
> +{
> +	int i;
> +	ssize_t bytes = 0;
> +	__be64 __iomem *fc_port;
> +
> +	if (port >= NUM_FC_PORTS)
> +		return 0;
> +
> +	fc_port = &afu->afu_map->global.fc_port[port][0];
> +
> +	for (i = 0; i < CXLFLASH_NUM_VLUNS; i++, buf += 22)

Rather than this bug prone hard coded 22, how about never incrementing buf and do something
similar to this:

> +		bytes += scnprintf(buf, PAGE_SIZE, "%03d: %016llX\n",
> +				   i, readq_be(&fc_port[i]));

		bytes += scnprintf(&buf[bytes], PAGE_SIZE, "%03d: %016llX\n",
				   i, readq_be(&fc_port[i]));

> +	return bytes;
> +}
> +

-- 
Brian King
Power Linux I/O
IBM Linux Technology Center