If a target disappears from the SCSI bus, NCR5380_select() may
subsequently fail with a time-out. In this situation, scsi_done is
called and NCR5380_select() returns 0. Both hostdata->connected and
hostdata->selecting are NULL and the main loop should proceed with
the next command in the issue queue. Clarify this logic.

Signed-off-by: Finn Thain <fth...@telegraphics.com.au>

---

Good code style would be,

        if (this) {
                /* do stuff */
        }

rather than,

        if (!this) {
        } else {
                /* do stuff */
        }

But I've used the latter form at this point in the series for a cleaner
diff between NCR5380.c and atari_NC5380.c, making it easier to gradually
reduce discrepancies. Code style gets fixed up along the way.

---
 drivers/scsi/NCR5380.c       |    8 ++++++--
 drivers/scsi/atari_NCR5380.c |    8 ++++----
 2 files changed, 10 insertions(+), 6 deletions(-)

Index: linux/drivers/scsi/NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/NCR5380.c   2015-11-18 19:33:21.000000000 +1100
+++ linux/drivers/scsi/NCR5380.c        2015-11-18 19:33:23.000000000 +1100
@@ -1007,14 +1007,18 @@ static void NCR5380_main(struct work_str
                                         */
 
                                        if (!NCR5380_select(instance, tmp)) {
-                                               break;
+                                               /* OK or bad target */
                                        } else {
+                                               /* Need to retry */
                                                LIST(tmp, 
hostdata->issue_queue);
                                                tmp->host_scribble = (unsigned 
char *) hostdata->issue_queue;
                                                hostdata->issue_queue = tmp;
                                                done = 0;
                                                
dprintk(NDEBUG_MAIN|NDEBUG_QUEUES, "scsi%d : main(): select() failed, returned 
to issue_queue\n", instance->host_no);
                                        }
+                                       if (hostdata->connected ||
+                                           hostdata->selecting)
+                                               break;
                                        /* lock held here still */
                                }       /* if target/lun is not busy */
                        }       /* for */
@@ -1024,7 +1028,7 @@ static void NCR5380_main(struct work_str
                        tmp = (struct scsi_cmnd *) hostdata->selecting;
                        /* Selection will drop and retake the lock */
                        if (!NCR5380_select(instance, tmp)) {
-                               /* Ok ?? */
+                               /* OK or bad target */
                        } else {
                                /* RvC: device failed, so we wait a long time
                                   this is needed for Mustek scanners, that
Index: linux/drivers/scsi/atari_NCR5380.c
===================================================================
--- linux.orig/drivers/scsi/atari_NCR5380.c     2015-11-18 19:33:21.000000000 
+1100
+++ linux/drivers/scsi/atari_NCR5380.c  2015-11-18 19:33:23.000000000 +1100
@@ -1139,13 +1139,13 @@ static void NCR5380_main(struct work_str
                                        cmd_get_tag(tmp, tmp->cmnd[0] != 
REQUEST_SENSE);
 #endif
                                        if (!NCR5380_select(instance, tmp)) {
+                                               /* OK or bad target */
                                                local_irq_disable();
                                                hostdata->retain_dma_intr--;
-                                               /* release if target did not 
response! */
                                                maybe_release_dma_irq(instance);
                                                local_irq_restore(flags);
-                                               break;
                                        } else {
+                                               /* Need to retry */
                                                local_irq_disable();
                                                LIST(tmp, 
hostdata->issue_queue);
                                                SET_NEXT(tmp, 
hostdata->issue_queue);
@@ -1157,9 +1157,9 @@ static void NCR5380_main(struct work_str
                                                local_irq_restore(flags);
                                                dprintk(NDEBUG_MAIN, "scsi%d: 
main(): select() failed, "
                                                            "returned to 
issue_queue\n", HOSTNO);
-                                               if (hostdata->connected)
-                                                       break;
                                        }
+                                       if (hostdata->connected)
+                                               break;
                                } /* if target/lun/target queue is not busy */
                        } /* for issue_queue */
                } /* if (!hostdata->connected) */


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