scsi: st: Separate st-unique ioctl handling from SCSI common ioctl handling

The st ioctl function currently interleaves code for handling various st
specific ioctls with parts of code needed for handling ioctls common to
all SCSI devices. Separate out st's code for the common ioctls into a
more manageable, separate function.

Signed-off-by: David Jeffery <djeffery@redhat.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Reviewed-by: John Meneghini <jmeneghi@redhat.com>
Tested-by: John Meneghini <jmeneghi@redhat.com>
Link: https://patch.msgid.link/20251104154709.6436-1-djeffery@redhat.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: David Jeffery

drivers/scsi/st.c

@@ -3526,8 +3526,60 @@ static int partition_tape(struct scsi_tape *STp, int size)
 out:
 	return result;
 }
-
 
+/*
+ * Handles any extra state needed for ioctls which are not st-specific.
+ * Called with the scsi_tape lock held, released before return
+ */
+static long st_common_ioctl(struct scsi_tape *STp, struct st_modedef *STm,
+			    struct file *file, unsigned int cmd_in,
+			    unsigned long arg)
+{
+	int i, retval = 0;
+
+	if (!STm->defined) {
+		retval = -ENXIO;
+		goto out;
+	}
+
+	if ((i = flush_buffer(STp, 0)) < 0) {
+		retval = i;
+		goto out;
+	} else { /* flush_buffer succeeds */
+		if (STp->can_partitions) {
+			i = switch_partition(STp);
+			if (i < 0) {
+				retval = i;
+				goto out;
+			}
+		}
+	}
+	mutex_unlock(&STp->lock);
+
+	switch (cmd_in) {
+	case SG_IO:
+	case SCSI_IOCTL_SEND_COMMAND:
+	case CDROM_SEND_PACKET:
+		if (!capable(CAP_SYS_RAWIO))
+			return -EPERM;
+		break;
+	default:
+		break;
+	}
+
+	retval = scsi_ioctl(STp->device, file->f_mode & FMODE_WRITE,
+			    cmd_in, (void __user *)arg);
+	if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) {
+		/* unload */
+		STp->rew_at_close = 0;
+		STp->ready = ST_NO_TAPE;
+	}
+
+	return retval;
+out:
+	mutex_unlock(&STp->lock);
+	return retval;
+}
 
 /* The ioctl command */
 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
@@ -3565,6 +3617,15 @@ static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
 	if (retval)
 		goto out;
 
+	switch (cmd_in) {
+	case MTIOCPOS:
+	case MTIOCGET:
+	case MTIOCTOP:
+		break;
+	default:
+		return st_common_ioctl(STp, STm, file, cmd_in, arg);
+	}
+
 	cmd_type = _IOC_TYPE(cmd_in);
 	cmd_nr = _IOC_NR(cmd_in);
 
@@ -3876,29 +3937,7 @@ static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
 		}
 		mt_pos.mt_blkno = blk;
 		retval = put_user_mtpos(p, &mt_pos);
-		goto out;
 	}
-	mutex_unlock(&STp->lock);
-
-	switch (cmd_in) {
-	case SG_IO:
-	case SCSI_IOCTL_SEND_COMMAND:
-	case CDROM_SEND_PACKET:
-		if (!capable(CAP_SYS_RAWIO))
-			return -EPERM;
-		break;
-	default:
-		break;
-	}
-
-	retval = scsi_ioctl(STp->device, file->f_mode & FMODE_WRITE, cmd_in, p);
-	if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) {
-		/* unload */
-		STp->rew_at_close = 0;
-		STp->ready = ST_NO_TAPE;
-	}
-	return retval;
-
  out:
 	mutex_unlock(&STp->lock);
 	return retval;