Re: [PATCH v5 10/10] scsi: Implement blk_mq_ops.show_rq()

Bart Van Assche
2017-04-25T22:06:24Z

On Tue, 2017-04-25 at 14:39 -0700, Omar Sandoval wrote:
> On Tue, Apr 25, 2017 at 01:37:45PM -0700, Bart Van Assche wrote:
> > Show the SCSI CDB, .eh_eflags and .result for pending SCSI commands
> > in /sys/kernel/debug/block/*/mq/*/dispatch and */rq_list.
>=20
> Only thing I noticed was that the only other caller I see has buf[70].
> No idea if that's a meaningful number. For the sake of this not getting
> bike-shedded to death,

Neither length is sufficient to avoid truncation of e.g. ATA pass-through
commands or commands with variable length CDBs. However, from the point of
view of debugging queue lockups the most useful information in a SCSI
command are the first two bytes of the CDB. The chosen buffer length is
definitely enough to make sure that these two bytes will be reported.

Bart.=