block: replace @ext_minors with GENHD_FL_EXT_DEVT

With previous changes, it's meaningless to limit the number of
partitions.  Replace @ext_minors with GENHD_FL_EXT_DEVT such that
setting the flag allows the disk to have maximum number of allowed
partitions (only limited by the number of entries in parsed_partitions
as determined by MAX_PART constant).

This kills not-too-pretty alloc_disk_ext[_node]() functions and makes
@minors parameter to alloc_disk[_node]() unnecessary.  The parameter
is left alone to avoid disturbing the users.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 280d231..6598024 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -86,16 +86,12 @@
 MODULE_ALIAS_SCSI_DEVICE(TYPE_MOD);
 MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);
 
-#define SD_PARTS	64
-
 #if !defined(CONFIG_DEBUG_BLOCK_EXT_DEVT)
 #define SD_MINORS	16
 #else
 #define SD_MINORS	1
 #endif
 
-#define SD_EXT_MINORS	(SD_PARTS - SD_MINORS)
-
 static int  sd_revalidate_disk(struct gendisk *);
 static int  sd_probe(struct device *);
 static int  sd_remove(struct device *);
@@ -1811,7 +1807,7 @@
 	if (!sdkp)
 		goto out;
 
-	gd = alloc_disk_ext(SD_MINORS, SD_EXT_MINORS);
+	gd = alloc_disk(SD_MINORS);
 	if (!gd)
 		goto out_free;
 
@@ -1856,7 +1852,6 @@
 	gd->major = sd_major((index & 0xf0) >> 4);
 	gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
 	gd->minors = SD_MINORS;
-	gd->ext_minors = SD_EXT_MINORS;
 	gd->fops = &sd_fops;
 
 	if (index < 26) {
@@ -1880,7 +1875,7 @@
 	blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
 
 	gd->driverfs_dev = &sdp->sdev_gendev;
-	gd->flags = GENHD_FL_DRIVERFS;
+	gd->flags = GENHD_FL_EXT_DEVT | GENHD_FL_DRIVERFS;
 	if (sdp->removable)
 		gd->flags |= GENHD_FL_REMOVABLE;