[PATCH 1/2] nvme: add set feature tracing support

[Max Gurtovoy]

On 7/5/2021 6:15 AM, Hou Pu wrote:
> A nvme connect command produces following trace.
>
> Before:
> /sys/kernel/debug/tracing# cat trace | grep feature
>      kworker/5:1H-98      [005] ....  3221.294844: nvme_setup_cmd: nvme0: qid=0, cmdid=25, nsid=0, flags=0x0, meta=0x0, cmd=(nvme_admin_set_features cdw10=07 00 00 00 07 00 07 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00)
>      kworker/4:1H-124     [004] ....  3222.009186: nvme_setup_cmd: nvme0: qid=0, cmdid=17, nsid=0, flags=0x0, meta=0x0, cmd=(nvme_admin_set_features cdw10=0b 00 00 00 00 09 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00)
>
> After:
> /sys/kernel/debug/tracing# cat trace | grep feature
>      kworker/0:1H-253     [000] ....   196.060509: nvme_setup_cmd: nvme0: qid=0, cmdid=29, nsid=0, flags=0x0, meta=0x0, cmd=(nvme_admin_set_features fid=0x7, sv=0x0, cdw11=0x70007)
>      kworker/0:1H-253     [000] ....   196.763947: nvme_setup_cmd: nvme0: qid=0, cmdid=29, nsid=0, flags=0x0, meta=0x0, cmd=(nvme_admin_set_features fid=0xb, sv=0x0, cdw11=0x900)
>
> Using ',' to separate different field like others in
> nvmet_trace_admin_get_features.
>
> Signed-off-by: Hou Pu <houpu.main at gmail.com>
> ---
>   drivers/nvme/host/trace.c | 18 +++++++++++++++++-
>   1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/trace.c b/drivers/nvme/host/trace.c
> index 6543015b6121..2a89c5aa0790 100644
> --- a/drivers/nvme/host/trace.c
> +++ b/drivers/nvme/host/trace.c
> @@ -72,6 +72,20 @@ static const char *nvme_trace_admin_identify(struct trace_seq *p, u8 *cdw10)
>   	return ret;
>   }
>   
> +static const char *nvme_trace_admin_set_features(struct trace_seq *p,
> +						 u8 *cdw10)
> +{
> +	const char *ret = trace_seq_buffer_ptr(p);
> +	u8 fid = cdw10[0];
> +	u8 sv = cdw10[3] & 0x8;
> +	u32 cdw11 = get_unaligned_le32(cdw10 + 4);

By the spec cdw10, 11, 12, 13, 14, 15 are used by set features command.

At least lets print cdw11-cdw15 as raw data and not only cdw11.

We don't want to loose information.

> +
> +	trace_seq_printf(p, "fid=0x%x, sv=0x%x, cdw11=0x%x", fid, sv, cdw11);
> +	trace_seq_putc(p, 0);
> +
> +	return ret;
> +}
> +
>   static const char *nvme_trace_admin_get_features(struct trace_seq *p,
>   						 u8 *cdw10)
>   {
> @@ -80,7 +94,7 @@ static const char *nvme_trace_admin_get_features(struct trace_seq *p,
>   	u8 sel = cdw10[1] & 0x7;
>   	u32 cdw11 = get_unaligned_le32(cdw10 + 4);
>   
> -	trace_seq_printf(p, "fid=0x%x sel=0x%x cdw11=0x%x", fid, sel, cdw11);
> +	trace_seq_printf(p, "fid=0x%x, sel=0x%x, cdw11=0x%x", fid, sel, cdw11);

This can be done in separate commit.

Also if you can fix the current status and print also cdw14 since it's 
used by get features by the spec (in separate commit).


>   	trace_seq_putc(p, 0);
>   
>   	return ret;
> @@ -201,6 +215,8 @@ const char *nvme_trace_parse_admin_cmd(struct trace_seq *p,
>   		return nvme_trace_create_cq(p, cdw10);
>   	case nvme_admin_identify:
>   		return nvme_trace_admin_identify(p, cdw10);
> +	case nvme_admin_set_features:
> +		return nvme_trace_admin_set_features(p, cdw10);
>   	case nvme_admin_get_features:
>   		return nvme_trace_admin_get_features(p, cdw10);
>   	case nvme_admin_get_lba_status: