block: move the misaligned flag into the features field

Move the misaligned flags into the features field to reclaim a little
bit of space.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240619154623.450048-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

block/blk-settings.c

@@ -258,7 +258,7 @@ static int blk_validate_limits(struct queue_limits *lim)
 
 	if (lim->alignment_offset) {
 		lim->alignment_offset &= (lim->physical_block_size - 1);
-		lim->misaligned = 0;
+		lim->features &= ~BLK_FEAT_MISALIGNED;
 	}
 
 	if (!(lim->features & BLK_FEAT_WRITE_CACHE))
@@ -470,6 +470,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 	if (!(b->features & BLK_FEAT_POLL))
 		t->features &= ~BLK_FEAT_POLL;
 
+	t->flags |= (b->flags & BLK_FEAT_MISALIGNED);
+
 	t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
 	t->max_user_sectors = min_not_zero(t->max_user_sectors,
 			b->max_user_sectors);
@@ -494,8 +496,6 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 	t->max_segment_size = min_not_zero(t->max_segment_size,
 					   b->max_segment_size);
 
-	t->misaligned |= b->misaligned;
-
 	alignment = queue_limit_alignment_offset(b, start);
 
 	/* Bottom device has different alignment.  Check that it is
@@ -509,7 +509,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 
 		/* Verify that top and bottom intervals line up */
 		if (max(top, bottom) % min(top, bottom)) {
-			t->misaligned = 1;
+			t->flags |= BLK_FEAT_MISALIGNED;
 			ret = -1;
 		}
 	}
@@ -531,28 +531,28 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 	/* Physical block size a multiple of the logical block size? */
 	if (t->physical_block_size & (t->logical_block_size - 1)) {
 		t->physical_block_size = t->logical_block_size;
-		t->misaligned = 1;
+		t->flags |= BLK_FEAT_MISALIGNED;
 		ret = -1;
 	}
 
 	/* Minimum I/O a multiple of the physical block size? */
 	if (t->io_min & (t->physical_block_size - 1)) {
 		t->io_min = t->physical_block_size;
-		t->misaligned = 1;
+		t->flags |= BLK_FEAT_MISALIGNED;
 		ret = -1;
 	}
 
 	/* Optimal I/O a multiple of the physical block size? */
 	if (t->io_opt & (t->physical_block_size - 1)) {
 		t->io_opt = 0;
-		t->misaligned = 1;
+		t->flags |= BLK_FEAT_MISALIGNED;
 		ret = -1;
 	}
 
 	/* chunk_sectors a multiple of the physical block size? */
 	if ((t->chunk_sectors << 9) & (t->physical_block_size - 1)) {
 		t->chunk_sectors = 0;
-		t->misaligned = 1;
+		t->flags |= BLK_FEAT_MISALIGNED;
 		ret = -1;
 	}
 
@@ -566,7 +566,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 
 	/* Verify that new alignment_offset is on a logical block boundary */
 	if (t->alignment_offset & (t->logical_block_size - 1)) {
-		t->misaligned = 1;
+		t->flags |= BLK_FEAT_MISALIGNED;
 		ret = -1;
 	}
 
@@ -729,7 +729,7 @@ int bdev_alignment_offset(struct block_device *bdev)
 {
 	struct request_queue *q = bdev_get_queue(bdev);
 
-	if (q->limits.misaligned)
+	if (q->limits.flags & BLK_FEAT_MISALIGNED)
 		return -1;
 	if (bdev_is_partition(bdev))
 		return queue_limit_alignment_offset(&q->limits,

include/linux/blkdev.h

@@ -341,6 +341,9 @@ enum {
 enum {
 	/* do not send FLUSH/FUA commands despite advertising a write cache */
 	BLK_FLAG_WRITE_CACHE_DISABLED		= (1u << 0),
+
+	/* I/O topology is misaligned */
+	BLK_FEAT_MISALIGNED			= (1u << 1),
 };
 
 struct queue_limits {
@@ -374,7 +377,6 @@ struct queue_limits {
 	unsigned short		max_integrity_segments;
 	unsigned short		max_discard_segments;
 
-	unsigned char		misaligned;
 	unsigned char		discard_misaligned;
 	unsigned char		raid_partial_stripes_expensive;
 	unsigned int		max_open_zones;