Re: [PATCH 2/2] scsi: add scsi trace core function and put tracepoints

From: Kei Tokunaga
Date: Sun Jan 31 2010 - 23:44:06 EST

Martin K. Petersen wrote:
>>>>>> "Kei" == Kei Tokunaga <tokunaga.keiich@xxxxxxxxxxxxxx> writes:
> + TP_printk("host_no=%u channel=%u id=%u lun=%u cmnd=(%s %s raw=%s) "
> ^^^^^^^^^^
> I'm not sure anybody cares about channels in this millennium so that may
> be a waste of space.
> +scsi_trace_rw10(struct trace_seq *p, unsigned char *cdb, int len)
> +scsi_trace_rw12(struct trace_seq *p, unsigned char *cdb, int len)
> +scsi_trace_rw16(struct trace_seq *p, unsigned char *cdb, int len)
> +scsi_trace_rw32(struct trace_seq *p, unsigned char *cdb, int len)
> Would be handy to get FUA and {RD,WR}PROTECT decoded in these commands.
> And prot_op would be nice too.
> Other decode-worthy commands might be WRITE SAME(16) and UNMAP.

Thanks for the suggestions. I'm going to post v2 series of this
patchset soon, and please note, in that version, I didn't add the
decoding on these stuff you mentioned above.

> +scsi_trace_parse_cdb(struct trace_seq *p, unsigned char *cdb, int len)
> +{
> [...]
> + case READ_32:
> + case WRITE_32:
> + return scsi_trace_rw32(p, cdb, len);
> This won't work. READ/WRITE(32) are variable length commands. They
> share the same operation code and are distinguished by the service
> action field. Several of the most recent additions to the SCSI
> protocols are implemented like this.
> Other commands requiring two-level parsing are READ CAPACITY(16) and GET

This is definitely a valid point. In the v2 patchset, I tried to
fix it. (Only DIF_TYPE2 READ/WRITE(32) are handled in that
version.) It'd be great if you would review it.

I'm sorry that I didn't reply sooner.


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