Re: [PATCH 02/13] iscsi: Add Serial Number Arithmetic LT and GT into iscsi_proto.h

["Nicholas A. Bellinger" <nab@linux-iscsi.org>]

On Sat, 2011-07-23 at 16:25 +0200, Jesper Juhl wrote:
> On Sat, 23 Jul 2011, Nicholas A. Bellinger wrote:
> 
> > From: Nicholas Bellinger <nab@linux-iscsi.org>
> > 
> > This patch moves the iscsi_sna_lt() and iscsi_sna_lte(), along with
> > iscsi_sna_gt() and iscsi_sna_gte() from iscsi_target_mod into
> > static inlines inside of include/scsi/iscsi_proto.h
> > 
> > This patch also includes the ISCSI_HDR_LEN and ISCSI_CRC_LEN
> > definitions.
> > 
> > Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
> > Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
> > Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
> > ---
> >  drivers/scsi/libiscsi.c    |   16 ----------------
> >  include/scsi/iscsi_proto.h |   38 ++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 38 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
> > index 9c3cb4e..3461a03 100644
> > --- a/drivers/scsi/libiscsi.c
> > +++ b/drivers/scsi/libiscsi.c
> > @@ -84,22 +84,6 @@ MODULE_PARM_DESC(debug_libiscsi_eh,
> >  					     __func__, ##arg);		\
> >  	} while (0);
> >  
> > -/* Serial Number Arithmetic, 32 bits, less than, RFC1982 */
> > -#define SNA32_CHECK 2147483648UL
> > -
> > -static int iscsi_sna_lt(u32 n1, u32 n2)
> > -{
> > -	return n1 != n2 && ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
> > -			    (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
> > -}
> > -
> > -/* Serial Number Arithmetic, 32 bits, less than, RFC1982 */
> > -static int iscsi_sna_lte(u32 n1, u32 n2)
> > -{
> > -	return n1 == n2 || ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
> > -			    (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
> > -}
> > -
> >  inline void iscsi_conn_queue_work(struct iscsi_conn *conn)
> >  {
> >  	struct Scsi_Host *shost = conn->session->host;
> > diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h
> > index a9c9058..455b03a 100644
> > --- a/include/scsi/iscsi_proto.h
> > +++ b/include/scsi/iscsi_proto.h
> > @@ -29,10 +29,48 @@
> >  /* default iSCSI listen port for incoming connections */
> >  #define ISCSI_LISTEN_PORT	3260
> >  
> > +/* iSCSI header length */
> > +#define ISCSI_HDR_LEN		48
> > +
> > +/* iSCSI CRC32C length */
> > +#define ISCSI_CRC_LEN		4
> > +
> >  /* Padding word length */
> >  #define ISCSI_PAD_LEN		4
> >  
> >  /*
> > + * Serial Number Arithmetic, 32 bits, RFC1982
> > + */
> > +
> > +static inline int iscsi_sna_lt(u32 n1, u32 n2)
> > +{
> > +	s32 diff = n1 - n2;
> > +
> > +	return diff < 0;
> > +}
> 
> Perhaps get rid of the variable and do
> 
>   return (s32)(n1 - n2) < 0;
> 
>  same suggestion for the other functions as well.
> 
> ???
> 

Seems like a reasonable simplfication to me.  Changing this now in
lio-core-2.6.git and respinning for an merge commit.

--nab

> > +
> > +static inline int iscsi_sna_lte(u32 n1, u32 n2)
> > +{
> > +	s32 diff = n1 - n2;
> > +
> > +	return diff <= 0;
> > +}
> > +
> > +static inline int iscsi_sna_gt(u32 n1, u32 n2)
> > +{
> > +	s32 diff = n1 - n2;
> > +
> > +	return diff > 0;
> > +}
> > +
> > +static inline int iscsi_sna_gte(u32 n1, u32 n2)
> > +{
> > +	s32 diff = n1 - n2;
> > +
> > +	return diff >= 0;
> > +}
> > +
> > +/*
> >   * useful common(control and data pathes) macro
> >   */
> >  #define ntoh24(p) (((p)[0] << 16) | ((p)[1] << 8) | ((p)[2]))
> > 
>