Re: [patch 04/16] git-scsi-misc: fix SCSI_DH build errors

[Chandra Seetharaman <sekharan@us.ibm.com>]

On Mon, 2008-07-07 at 17:10 -0500, James Bottomley wrote:
> On Thu, 2008-07-03 at 23:47 -0700, akpm@linux-foundation.org wrote:
> > From: Chandra Seetharaman <sekharan@us.ibm.com>
> > 
> > Do not automatically "select" SCSI_DH for dm-multipath. If SCSI_DH
> > doesn't exist, just do not allow  hardware handlers to be used.
> > 
> > Handle SCSI_DH being a module also. Make sure it doesn't allow DM_MULTIPATH
> > to be compiled in when SCSI_DH is a module.
> > 
> > Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
> > Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
> > Reported-by: Andrew Morton <akpm@linux-foundation.org>
> > Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> > Cc: Alasdair G Kergon <agk@redhat.com>
> > Cc: Mike Christie <michaelc@cs.wisc.edu>
> > Cc: Mike Anderson <andmike@us.ibm.com>
> > Cc: Hannes Reinecke <hare@suse.de>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> > 
> >  drivers/md/Kconfig     |    2 +-
> >  drivers/md/dm-mpath.c  |    2 ++
> >  include/scsi/scsi_dh.h |   12 +++++++++++-
> >  3 files changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff -puN drivers/md/Kconfig~git-scsi-misc-fix-scsi_dh-build-errors drivers/md/Kconfig
> > --- a/drivers/md/Kconfig~git-scsi-misc-fix-scsi_dh-build-errors
> > +++ a/drivers/md/Kconfig
> > @@ -252,7 +252,7 @@ config DM_ZERO
> >  config DM_MULTIPATH
> >  	tristate "Multipath target"
> >  	depends on BLK_DEV_DM
> > -	select SCSI_DH
> > +	depends on SCSI_DH || !SCSI_DH
> 
> This is a bit horrible.  It's not very obvious what it means and it
> critically depends on the current !m == m behaviour.

I couldn't find other way to solve this dependency. Will look into that
again.

> 
> >  	---help---
> >  	  Allow volume managers to support multipath hardware.
> >  
> > diff -puN drivers/md/dm-mpath.c~git-scsi-misc-fix-scsi_dh-build-errors drivers/md/dm-mpath.c
> > --- a/drivers/md/dm-mpath.c~git-scsi-misc-fix-scsi_dh-build-errors
> > +++ a/drivers/md/dm-mpath.c
> > @@ -664,6 +664,8 @@ static int parse_hw_handler(struct arg_s
> >  	request_module("scsi_dh_%s", m->hw_handler_name);
> >  	if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {
> >  		ti->error = "unknown hardware handler type";
> > +		kfree(m->hw_handler_name);
> > +		m->hw_handler_name = NULL;
> 
> This looks like some type of separate bug fix ... it's certainly not
> mentioned in the change log and has nothing to do with modular compile
> problems.

That is true. I can create a separate patch for this.
> 
> James
> 
> 
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