Re: [PATCH] libata: remove unlock+relock cycle in ata_scsi_queuecmd

[James Bottomley <James.Bottomley@suse.de>]

On Wed, 2010-11-17 at 10:47 -0500, Christoph Hellwig wrote:
> > Right ... I couldn't persuade anyone else to do it, so I'll probably end
> > up coding it.  It looks like the serial number zero check might be
> > bogus.  If so I'll remove it, then push the serial number acquisition
> > down only into the locked queuecommand of only those drivers that
> > actually use it (which were listed in the quoted email, and which might
> > have a big impetus to remove it if the use is trivial).  Then we can
> > begin unwinding the locking.
> 
> In dc395x, eata_pio, in2000, lpfc, megaraid_legacy, megaraid_mbox,
> megaraid_sas, mesh, ncr53c8xx, qla1280, qla4xxx, wd33c93 and i2o_scsi
> use it in printks only, and all this can be safely removed.
> 
> Except for EH that only leaves dpt_i2o, eata, mpt2sas, u14-34f, mptscsi
> as non-trivial users.  If you sort out the EH side I'll volunteer to
> kill the printks and add private serial numbers to the five drivers
> mentioned above.

You're on (you were cc'd on the patch) ... I was planning just to move
the scsi_cmnd_get_serial() call into the locked queuecommand routine,
but a more permanent solution might be better.

James