From: Finn Thain <fthain@telegraphics.com.au>
Date: Thu, 27 Sep 2018 11:17:11 +1000
Subject: scsi: NCR5380: Have NCR5380_select() return a bool
Git-commit: dad8261e643849ea134c7cd5c8e794e31d93b9eb
Patch-mainline: v4.20-rc1
References: git-fixes

The return value is taken to mean "retry" or "don't retry". Change it to bool
to improve readability. Fix related comments. No functional change.

Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Lee Duncan <lduncan@suse.com>
---
 drivers/scsi/NCR5380.c |   40 ++++++++++++++++++----------------------
 drivers/scsi/NCR5380.h |    2 +-
 2 files changed, 19 insertions(+), 23 deletions(-)

--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -901,20 +901,16 @@ static irqreturn_t __maybe_unused NCR538
 	return IRQ_RETVAL(handled);
 }
 
-/*
- * Function : int NCR5380_select(struct Scsi_Host *instance,
- * struct scsi_cmnd *cmd)
- *
- * Purpose : establishes I_T_L or I_T_L_Q nexus for new or existing command,
- * including ARBITRATION, SELECTION, and initial message out for
- * IDENTIFY and queue messages.
+/**
+ * NCR5380_select - attempt arbitration and selection for a given command
+ * @instance: the Scsi_Host instance
+ * @cmd: the scsi_cmnd to execute
  *
- * Inputs : instance - instantiation of the 5380 driver on which this
- * target lives, cmd - SCSI command to execute.
+ * This routine establishes an I_T_L nexus for a SCSI command. This involves
+ * ARBITRATION, SELECTION and MESSAGE OUT phases and an IDENTIFY message.
  *
- * Returns cmd if selection failed but should be retried,
- * NULL if selection failed and should not be retried, or
- * NULL if selection succeeded (hostdata->connected == cmd).
+ * Returns true if the operation should be retried.
+ * Returns false if it should not be retried.
  *
  * Side effects :
  * If bus busy, arbitration failed, etc, NCR5380_select() will exit
@@ -922,16 +918,15 @@ static irqreturn_t __maybe_unused NCR538
  * SELECT_ENABLE will be set appropriately, the NCR5380
  * will cease to drive any SCSI bus signals.
  *
- * If successful : I_T_L or I_T_L_Q nexus will be established,
- * instance->connected will be set to cmd.
+ * If successful : the I_T_L nexus will be established, and
+ * hostdata->connected will be set to cmd.
  * SELECT interrupt will be disabled.
  *
  * If failed (no target) : cmd->scsi_done() will be called, and the
  * cmd->result host byte set to DID_BAD_TARGET.
  */
 
-static struct scsi_cmnd *NCR5380_select(struct Scsi_Host *instance,
-                                        struct scsi_cmnd *cmd)
+static bool NCR5380_select(struct Scsi_Host *instance, struct scsi_cmnd *cmd)
 	__releases(&hostdata->lock) __acquires(&hostdata->lock)
 {
 	struct NCR5380_hostdata *hostdata = shost_priv(instance);
@@ -939,6 +934,7 @@ static struct scsi_cmnd *NCR5380_select(
 	unsigned char *data;
 	int len;
 	int err;
+	bool ret = true;
 
 	NCR5380_dprint(NDEBUG_ARBITRATION, instance);
 	dsprintk(NDEBUG_ARBITRATION, instance, "starting arbitration, id = %d\n",
@@ -947,7 +943,7 @@ static struct scsi_cmnd *NCR5380_select(
 	/*
 	 * Arbitration and selection phases are slow and involve dropping the
 	 * lock, so we have to watch out for EH. An exception handler may
-	 * change 'selecting' to NULL. This function will then return NULL
+	 * change 'selecting' to NULL. This function will then return false
 	 * so that the caller will forget about 'cmd'. (During information
 	 * transfer phases, EH may change 'connected' to NULL.)
 	 */
@@ -1120,7 +1116,7 @@ static struct scsi_cmnd *NCR5380_select(
 			cmd->result = DID_BAD_TARGET << 16;
 			complete_cmd(instance, cmd);
 			dsprintk(NDEBUG_SELECTION, instance, "target did not respond within 250ms\n");
-			cmd = NULL;
+			ret = false;
 		}
 		goto out;
 	}
@@ -1170,7 +1166,7 @@ static struct scsi_cmnd *NCR5380_select(
 		cmd->result = DID_ERROR << 16;
 		complete_cmd(instance, cmd);
 		dsprintk(NDEBUG_SELECTION, instance, "IDENTIFY message transfer failed\n");
-		cmd = NULL;
+		ret = false;
 		goto out;
 	}
 
@@ -1185,13 +1181,13 @@ static struct scsi_cmnd *NCR5380_select(
 
 	initialize_SCp(cmd);
 
-	cmd = NULL;
+	ret = false;
 
 out:
 	if (!hostdata->selecting)
-		return NULL;
+		return NULL;	/* lduncan: should this be returning "false"? */
 	hostdata->selecting = NULL;
-	return cmd;
+	return ret;
 }
 
 /*
--- a/drivers/scsi/NCR5380.h
+++ b/drivers/scsi/NCR5380.h
@@ -274,7 +274,7 @@ static irqreturn_t NCR5380_intr(int irq,
 static void NCR5380_main(struct work_struct *work);
 static const char *NCR5380_info(struct Scsi_Host *instance);
 static void NCR5380_reselect(struct Scsi_Host *instance);
-static struct scsi_cmnd *NCR5380_select(struct Scsi_Host *, struct scsi_cmnd *);
+static bool NCR5380_select(struct Scsi_Host *, struct scsi_cmnd *);
 static int NCR5380_transfer_dma(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data);
 static int NCR5380_transfer_pio(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data);
 static int NCR5380_poll_politely2(struct NCR5380_hostdata *,