ide: ide_id_has_flush_cache() -> ata_id_flush_enabled()

* Add ata_id_flush_enabled() inline helper to <linux/ata.h>.

* ide_id_has_flush_cache() -> ata_id_flush_enabled()

  The latter one also checks if the command is marked as
  supported in word 83 and validity of words 83 & 86.

Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-disk.c

@@ -651,7 +651,7 @@ static void update_ordered(ide_drive_t *drive)
 		 * not available so we don't need to recheck that.
 		 */
 		capacity = idedisk_capacity(drive);
-		barrier = ide_id_has_flush_cache(id) && !drive->noflush &&
+		barrier = ata_id_flush_enabled(id) && !drive->noflush &&
 			(drive->addressing == 0 || capacity <= (1ULL << 28) ||
 			 ide_id_has_flush_cache_ext(id));
 
@@ -678,7 +678,7 @@ static int set_wcache(ide_drive_t *drive, int arg)
 	if (arg < 0 || arg > 1)
 		return -EINVAL;
 
-	if (ide_id_has_flush_cache(drive->id)) {
+	if (ata_id_flush_enabled(drive->id)) {
 		memset(&args, 0, sizeof(ide_task_t));
 		args.tf.feature = arg ?
 			SETFEATURES_WC_ON : SETFEATURES_WC_OFF;
@@ -886,7 +886,7 @@ static void idedisk_setup(ide_drive_t *drive)
 
 static void ide_cacheflush_p(ide_drive_t *drive)
 {
-	if (!drive->wcache || !ide_id_has_flush_cache(drive->id))
+	if (!drive->wcache || ata_id_flush_enabled(drive->id) == 0)
 		return;
 
 	if (do_idedisk_flushcache(drive))

drivers/ide/ide-io.c

@@ -184,7 +184,7 @@ static ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *
 		if (drive->media != ide_disk)
 			break;
 		/* Not supported? Switch to next step now. */
-		if (!drive->wcache || !ide_id_has_flush_cache(drive->id)) {
+		if (!drive->wcache || ata_id_flush_enabled(drive->id) == 0) {
 			ide_complete_power_step(drive, rq, 0, 0);
 			return ide_stopped;
 		}

include/linux/ata.h

@@ -558,6 +558,15 @@ static inline int ata_id_has_flush(const u16 *id)
 	return id[ATA_ID_COMMAND_SET_2] & (1 << 12);
 }
 
+static inline int ata_id_flush_enabled(const u16 *id)
+{
+	if (ata_id_has_flush(id) == 0)
+		return 0;
+	if ((id[ATA_ID_CSF_DEFAULT] & 0xC000) != 0x4000)
+		return 0;
+	return id[ATA_ID_CFS_ENABLE_2] & (1 << 12);
+}
+
 static inline int ata_id_has_flush_ext(const u16 *id)
 {
 	if ((id[ATA_ID_COMMAND_SET_2] & 0xC000) != 0x4000)

include/linux/ide.h

@@ -1453,9 +1453,6 @@ extern struct mutex ide_cfg_mtx;
 extern struct bus_type ide_bus_type;
 extern struct class *ide_port_class;
 
-/* check if CACHE FLUSH command is supported (as defined in ATA-6) */
-#define ide_id_has_flush_cache(id)	((id)[ATA_ID_CFS_ENABLE_2] & 0x1000)
-
 /* some Maxtor disks have bit 13 defined incorrectly so check bit 10 too */
 #define ide_id_has_flush_cache_ext(id)	\
 	(((id)[ATA_ID_CFS_ENABLE_2] & 0x2400) == 0x2400)