ata: libata: Introduce ata_ncq_supported()

Introduce the inline helper function ata_ncq_supported() to test if a
device supports NCQ commands. The function ata_ncq_enabled() is also
rewritten using this new helper function.
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>

include/linux/libata.h

@@ -1691,21 +1691,35 @@ extern struct ata_device *ata_dev_next(struct ata_device *dev,
 	     (dev) = ata_dev_next((dev), (link), ATA_DITER_##mode))
 
 /**
- *	ata_ncq_enabled - Test whether NCQ is enabled
- *	@dev: ATA device to test for
+ *	ata_ncq_supported - Test whether NCQ is supported
+ *	@dev: ATA device to test
  *
  *	LOCKING:
  *	spin_lock_irqsave(host lock)
  *
  *	RETURNS:
- *	1 if NCQ is enabled for @dev, 0 otherwise.
+ *	true if @dev supports NCQ, false otherwise.
  */
-static inline int ata_ncq_enabled(struct ata_device *dev)
+static inline bool ata_ncq_supported(struct ata_device *dev)
 {
 	if (!IS_ENABLED(CONFIG_SATA_HOST))
-		return 0;
-	return (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ_OFF |
-			      ATA_DFLAG_NCQ)) == ATA_DFLAG_NCQ;
+		return false;
+	return (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ)) == ATA_DFLAG_NCQ;
+}
+
+/**
+ *	ata_ncq_enabled - Test whether NCQ is enabled
+ *	@dev: ATA device to test
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host lock)
+ *
+ *	RETURNS:
+ *	true if NCQ is enabled for @dev, false otherwise.
+ */
+static inline bool ata_ncq_enabled(struct ata_device *dev)
+{
+	return ata_ncq_supported(dev) && !(dev->flags & ATA_DFLAG_NCQ_OFF);
 }
 
 static inline bool ata_fpdma_dsm_supported(struct ata_device *dev)