[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