[PATCH 26/26] block: move the bounce flag into the features field

[Christoph Hellwig <hch@xxxxxx>]

Move the bounce flag into the features field to reclaim a little bit of
space.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
 block/blk-settings.c    | 1 -
 block/blk.h             | 2 +-
 drivers/scsi/scsi_lib.c | 2 +-
 include/linux/blkdev.h  | 6 ++++--
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 96e07f24bd9aa1..d0e9096f93ca8a 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -479,7 +479,6 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 					b->max_write_zeroes_sectors);
 	t->max_zone_append_sectors = min(queue_limits_max_zone_append_sectors(t),
 					 queue_limits_max_zone_append_sectors(b));
-	t->bounce = max(t->bounce, b->bounce);
 
 	t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
 					    b->seg_boundary_mask);
diff --git a/block/blk.h b/block/blk.h
index 79e8d5d4fe0caf..fa32f7fad5d7e6 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -394,7 +394,7 @@ struct bio *__blk_queue_bounce(struct bio *bio, struct request_queue *q);
 static inline bool blk_queue_may_bounce(struct request_queue *q)
 {
 	return IS_ENABLED(CONFIG_BOUNCE) &&
-		q->limits.bounce == BLK_BOUNCE_HIGH &&
+		(q->limits.features & BLK_FEAT_BOUNCE_HIGH) &&
 		max_low_pfn >= max_pfn;
 }
 
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 54f771ec8cfb5e..e2f7bfb2b9e450 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1986,7 +1986,7 @@ void scsi_init_limits(struct Scsi_Host *shost, struct queue_limits *lim)
 		shost->dma_alignment, dma_get_cache_alignment() - 1);
 
 	if (shost->no_highmem)
-		lim->bounce = BLK_BOUNCE_HIGH;
+		lim->features |= BLK_FEAT_BOUNCE_HIGH;
 
 	dma_set_seg_boundary(dev, shost->dma_boundary);
 	dma_set_max_seg_size(dev, shost->max_segment_size);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 2c433ebf6f2030..e96ba7b97288d2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -325,6 +325,9 @@ enum {
 
 	/* skip this queue in blk_mq_(un)quiesce_tagset */
 	BLK_FEAT_SKIP_TAGSET_QUIESCE		= (1u << 13),
+
+	/* bounce all highmem pages */
+	BLK_FEAT_BOUNCE_HIGH			= (1u << 14),
 };
 
 /*
@@ -332,7 +335,7 @@ enum {
  */
 #define BLK_FEAT_INHERIT_MASK \
 	(BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA | BLK_FEAT_ROTATIONAL | \
-	 BLK_FEAT_STABLE_WRITES | BLK_FEAT_ZONED)
+	 BLK_FEAT_STABLE_WRITES | BLK_FEAT_ZONED | BLK_FEAT_BOUNCE_HIGH)
 
 /* internal flags in queue_limits.flags */
 enum {
@@ -352,7 +355,6 @@ enum blk_bounce {
 struct queue_limits {
 	unsigned int		features;
 	unsigned int		flags;
-	enum blk_bounce		bounce;
 	unsigned long		seg_boundary_mask;
 	unsigned long		virt_boundary_mask;
 
-- 
2.43.0