[SCSI] sym53c8xx: don't flood syslog with negotiation messages

sym53c8xx prints a negotiation message after every check condition.
This can add up to a lot of messages for removable-medium devices
(CD-ROM, tape drives, etc.) that are being polled, since they return
check condition when no medium is present.  This patch suppresses the
negotiation message if it would be the same as the last one printed.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/sym53c8xx_2/sym_hipd.c

@@ -2039,6 +2039,29 @@ static void sym_settrans(struct sym_hcb *np, int target, u_char opts, u_char ofs
 	}
 }
 
+static void sym_announce_transfer_rate(struct sym_tcb *tp)
+{
+	struct scsi_target *starget = tp->starget;
+
+	if (tp->tprint.period != spi_period(starget) ||
+	    tp->tprint.offset != spi_offset(starget) ||
+	    tp->tprint.width != spi_width(starget) ||
+	    tp->tprint.iu != spi_iu(starget) ||
+	    tp->tprint.dt != spi_dt(starget) ||
+	    tp->tprint.qas != spi_qas(starget) ||
+	    !tp->tprint.check_nego) {
+		tp->tprint.period = spi_period(starget);
+		tp->tprint.offset = spi_offset(starget);
+		tp->tprint.width = spi_width(starget);
+		tp->tprint.iu = spi_iu(starget);
+		tp->tprint.dt = spi_dt(starget);
+		tp->tprint.qas = spi_qas(starget);
+		tp->tprint.check_nego = 1;
+
+		spi_display_xfer_agreement(starget);
+	}
+}
+
 /*
  *  We received a WDTR.
  *  Let everything be aware of the changes.
@@ -2064,7 +2087,7 @@ static void sym_setwide(struct sym_hcb *np, int target, u_char wide)
 	spi_qas(starget) = 0;
 
 	if (sym_verbose >= 3)
-		spi_display_xfer_agreement(starget);
+		sym_announce_transfer_rate(tp);
 }
 
 /*
@@ -2097,7 +2120,7 @@ sym_setsync(struct sym_hcb *np, int target,
 		tp->tgoal.check_nego = 0;
 	}
 
-	spi_display_xfer_agreement(starget);
+	sym_announce_transfer_rate(tp);
 }
 
 /*
@@ -2125,7 +2148,7 @@ sym_setpprot(struct sym_hcb *np, int target, u_char opts, u_char ofs,
 	spi_qas(starget) = tp->tgoal.qas = !!(opts & PPR_OPT_QAS);
 	tp->tgoal.check_nego = 0;
 
-	spi_display_xfer_agreement(starget);
+	sym_announce_transfer_rate(tp);
 }
 
 /*

drivers/scsi/sym53c8xx_2/sym_hipd.h

@@ -420,6 +420,9 @@ struct sym_tcb {
 	/* Transfer goal */
 	struct sym_trans tgoal;
 
+	/* Last printed transfer speed */
+	struct sym_trans tprint;
+
 	/*
 	 * Keep track of the CCB used for the negotiation in order
 	 * to ensure that only 1 negotiation is queued at a time.