ide: idedisk_supports_lba48() -> ata_id_lba48_enabled()

* Add ata_id_lba48_enabled() inline helper to <linux/ata.h>.

* idedisk_supports_lba48() -> ata_id_lba48_enabled()

  The latter one also checks validity of words 83 & 86.

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

drivers/ide/ide-disk.c

@@ -383,16 +383,6 @@ static unsigned long long sectors_to_MB(unsigned long long n)
 	return n;
 }
 
-/*
- * The same here.
- */
-static inline int idedisk_supports_lba48(const u16 *id)
-{
-	return (id[ATA_ID_COMMAND_SET_2] & 0x0400) &&
-	       (id[ATA_ID_CFS_ENABLE_2] & 0x0400) &&
-	       ata_id_u64(id, ATA_ID_LBA_CAPACITY_2);
-}
-
 /*
  * Some disks report total number of sectors instead of
  * maximum sector address.  We list them here.
@@ -407,7 +397,7 @@ static const struct drive_list_entry hpa_list[] = {
 static void idedisk_check_hpa(ide_drive_t *drive)
 {
 	unsigned long long capacity, set_max;
-	int lba48 = idedisk_supports_lba48(drive->id);
+	int lba48 = ata_id_lba48_enabled(drive->id);
 
 	capacity = drive->capacity64;
 
@@ -450,7 +440,7 @@ static void init_idedisk_capacity(ide_drive_t *drive)
 	 */
 	int hpa = ata_id_hpa_enabled(id);
 
-	if (idedisk_supports_lba48(id)) {
+	if (ata_id_lba48_enabled(id)) {
 		/* drive speaks 48-bit LBA */
 		drive->select.b.lba = 1;
 		drive->capacity64 = ata_id_u64(id, ATA_ID_LBA_CAPACITY_2);
@@ -754,9 +744,11 @@ static int set_lba_addressing(ide_drive_t *drive, int arg)
 	if (drive->hwif->host_flags & IDE_HFLAG_NO_LBA48)
 		return 0;
 
-	if (!idedisk_supports_lba48(drive->id))
+	if (ata_id_lba48_enabled(drive->id) == 0)
 		return -EIO;
+
 	drive->addressing = arg;
+
 	return 0;
 }
 
@@ -853,8 +845,7 @@ static void idedisk_setup(ide_drive_t *drive)
 	capacity = idedisk_capacity(drive);
 
 	if (!drive->forced_geom) {
-
-		if (idedisk_supports_lba48(drive->id)) {
+		if (ata_id_lba48_enabled(drive->id)) {
 			/* compatibility */
 			drive->bios_sect = 63;
 			drive->bios_head = 255;

include/linux/ata.h

@@ -574,6 +574,15 @@ static inline int ata_id_has_lba48(const u16 *id)
 	return id[ATA_ID_COMMAND_SET_2] & (1 << 10);
 }
 
+static inline int ata_id_lba48_enabled(const u16 *id)
+{
+	if (ata_id_has_lba48(id) == 0)
+		return 0;
+	if ((id[ATA_ID_CSF_DEFAULT] & 0xC000) != 0x4000)
+		return 0;
+	return id[ATA_ID_CFS_ENABLE_2] & (1 << 10);
+}
+
 static inline int ata_id_hpa_enabled(const u16 *id)
 {
 	/* Yes children, word 83 valid bits cover word 82 data */