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

From: Nicholas A. Bellinger
Date: Sat Jul 23 2011 - 17:38:50 EST


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@xxxxxxxxxxxxxxx>
> >
> > 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@xxxxxxxxx>
> > Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
> > Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
> > ---
> > 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]))
> >
>

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