bdev: move ->bd_has_subit_bio to ->__bd_flags

In bdev_alloc() we have all flags initialized to false, so
assignment to ->bh_has_submit_bio n there is a no-op unless
we have partno != 0 and flag already set on entire device.

In device_add_disk() we have just allocated the block_device
in question and it had been a full-device one, so the flag
is guaranteed to be still clear when we get to assignment.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Author: Al Viro

block/bdev.c

@@ -414,10 +414,8 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 	atomic_set(&bdev->__bd_flags, partno);
 	bdev->bd_inode = inode;
 	bdev->bd_queue = disk->queue;
-	if (partno)
-		bdev->bd_has_submit_bio = disk->part0->bd_has_submit_bio;
-	else
-		bdev->bd_has_submit_bio = false;
+	if (partno && bdev_test_flag(disk->part0, BD_HAS_SUBMIT_BIO))
+		bdev_set_flag(bdev, BD_HAS_SUBMIT_BIO);
 	bdev->bd_stats = alloc_percpu(struct disk_stats);
 	if (!bdev->bd_stats) {
 		iput(inode);

block/blk-core.c

@@ -615,7 +615,7 @@ static void __submit_bio(struct bio *bio)
 	if (unlikely(!blk_crypto_bio_prep(&bio)))
 		return;
 
-	if (!bio->bi_bdev->bd_has_submit_bio) {
+	if (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO)) {
 		blk_mq_submit_bio(bio);
 	} else if (likely(bio_queue_enter(bio) == 0)) {
 		struct gendisk *disk = bio->bi_bdev->bd_disk;
@@ -723,7 +723,7 @@ void submit_bio_noacct_nocheck(struct bio *bio)
 	 */
 	if (current->bio_list)
 		bio_list_add(&current->bio_list[0], bio);
-	else if (!bio->bi_bdev->bd_has_submit_bio)
+	else if (!bdev_test_flag(bio->bi_bdev, BD_HAS_SUBMIT_BIO))
 		__submit_bio_noacct_mq(bio);
 	else
 		__submit_bio_noacct(bio);

block/genhd.c

@@ -413,7 +413,8 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 	elevator_init_mq(disk->queue);
 
 	/* Mark bdev as having a submit_bio, if needed */
-	disk->part0->bd_has_submit_bio = disk->fops->submit_bio != NULL;
+	if (disk->fops->submit_bio)
+		bdev_set_flag(disk->part0, BD_HAS_SUBMIT_BIO);
 
 	/*
 	 * If the driver provides an explicit major number it also must provide

include/linux/blk_types.h

@@ -49,7 +49,7 @@ struct block_device {
 #define BD_PARTNO		255	// lower 8 bits; assign-once
 #define BD_READ_ONLY		(1u<<8) // read-only policy
 #define BD_WRITE_HOLDER		(1u<<9)
-	bool			bd_has_submit_bio;
+#define BD_HAS_SUBMIT_BIO	(1u<<10)
 	dev_t			bd_dev;
 	struct inode		*bd_inode;	/* will die */