[PATCH 20/26] block: move the dax flag to queue_limits

[Christoph Hellwig <hch@xxxxxx>]

Move the dax flag into the queue_limits feature field so that it can be
set atomically with the queue frozen.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
 block/blk-mq-debugfs.c       | 1 -
 drivers/md/dm-table.c        | 4 ++--
 drivers/nvdimm/pmem.c        | 7 ++-----
 drivers/s390/block/dcssblk.c | 2 +-
 include/linux/blkdev.h       | 6 ++++--
 5 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 62b132e9a9ce3b..f4fa820251ce83 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -88,7 +88,6 @@ static const char *const blk_queue_flag_name[] = {
        QUEUE_FLAG_NAME(SAME_FORCE),
        QUEUE_FLAG_NAME(INIT_DONE),
        QUEUE_FLAG_NAME(POLL),
-       QUEUE_FLAG_NAME(DAX),
        QUEUE_FLAG_NAME(STATS),
        QUEUE_FLAG_NAME(REGISTERED),
        QUEUE_FLAG_NAME(QUIESCED),
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 84d636712c7284..e44697037e86f4 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1834,11 +1834,11 @@ int dm_table_set_restrictions(struct dm_table *t, 
struct request_queue *q,
                limits->features |= BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA;
 
        if (dm_table_supports_dax(t, device_not_dax_capable)) {
-               blk_queue_flag_set(QUEUE_FLAG_DAX, q);
+               limits->features |= BLK_FEAT_DAX;
                if (dm_table_supports_dax(t, 
device_not_dax_synchronous_capable))
                        set_dax_synchronous(t->md->dax_dev);
        } else
-               blk_queue_flag_clear(QUEUE_FLAG_DAX, q);
+               limits->features &= ~BLK_FEAT_DAX;
 
        if (dm_table_any_dev_attr(t, device_dax_write_cache_enabled, NULL))
                dax_write_cache(t->md->dax_dev, true);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index b821dcf018f6ae..1dd74c969d5a09 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -465,7 +465,6 @@ static int pmem_attach_disk(struct device *dev,
        struct dax_device *dax_dev;
        struct nd_pfn_sb *pfn_sb;
        struct pmem_device *pmem;
-       struct request_queue *q;
        struct gendisk *disk;
        void *addr;
        int rc;
@@ -499,6 +498,8 @@ static int pmem_attach_disk(struct device *dev,
        }
        if (fua)
                lim.features |= BLK_FEAT_FUA;
+       if (is_nd_pfn(dev))
+               lim.features |= BLK_FEAT_DAX;
 
        if (!devm_request_mem_region(dev, res->start, resource_size(res),
                                dev_name(&ndns->dev))) {
@@ -509,7 +510,6 @@ static int pmem_attach_disk(struct device *dev,
        disk = blk_alloc_disk(&lim, nid);
        if (IS_ERR(disk))
                return PTR_ERR(disk);
-       q = disk->queue;
 
        pmem->disk = disk;
        pmem->pgmap.owner = pmem;
@@ -547,9 +547,6 @@ static int pmem_attach_disk(struct device *dev,
        }
        pmem->virt_addr = addr;
 
-       if (pmem->pfn_flags & PFN_MAP)
-               blk_queue_flag_set(QUEUE_FLAG_DAX, q);
-
        disk->fops              = &pmem_fops;
        disk->private_data      = pmem;
        nvdimm_namespace_disk_name(ndns, disk->disk_name);
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 6d1689a2717e5f..d5a5d11ae0dcdf 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -548,6 +548,7 @@ dcssblk_add_store(struct device *dev, struct 
device_attribute *attr, const char
 {
        struct queue_limits lim = {
                .logical_block_size     = 4096,
+               .features               = BLK_FEAT_DAX,
        };
        int rc, i, j, num_of_segments;
        struct dcssblk_dev_info *dev_info;
@@ -643,7 +644,6 @@ dcssblk_add_store(struct device *dev, struct 
device_attribute *attr, const char
        dev_info->gd->fops = &dcssblk_devops;
        dev_info->gd->private_data = dev_info;
        dev_info->gd->flags |= GENHD_FL_NO_PART;
-       blk_queue_flag_set(QUEUE_FLAG_DAX, dev_info->gd->queue);
 
        seg_byte_size = (dev_info->end - dev_info->start + 1);
        set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f3d4519d609d95..7022e06a3dd9a3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -307,6 +307,9 @@ enum {
 
        /* supports REQ_NOWAIT */
        BLK_FEAT_NOWAIT                         = (1u << 7),
+
+       /* supports DAX */
+       BLK_FEAT_DAX                            = (1u << 8),
 };
 
 /*
@@ -575,7 +578,6 @@ struct request_queue {
 #define QUEUE_FLAG_SAME_FORCE  12      /* force complete on same CPU */
 #define QUEUE_FLAG_INIT_DONE   14      /* queue is initialized */
 #define QUEUE_FLAG_POLL                16      /* IO polling enabled if set */
-#define QUEUE_FLAG_DAX         19      /* device supports DAX */
 #define QUEUE_FLAG_STATS       20      /* track IO start and completion times 
*/
 #define QUEUE_FLAG_REGISTERED  22      /* queue has been registered to a disk 
*/
 #define QUEUE_FLAG_QUIESCED    24      /* queue has been quiesced */
@@ -602,7 +604,7 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct 
request_queue *q);
 #define blk_queue_io_stat(q)   ((q)->limits.features & BLK_FEAT_IO_STAT)
 #define blk_queue_zone_resetall(q)     \
        test_bit(QUEUE_FLAG_ZONE_RESETALL, &(q)->queue_flags)
-#define blk_queue_dax(q)       test_bit(QUEUE_FLAG_DAX, &(q)->queue_flags)
+#define blk_queue_dax(q)       ((q)->limits.features & BLK_FEAT_DAX)
 #define blk_queue_pci_p2pdma(q)        \
        test_bit(QUEUE_FLAG_PCI_P2PDMA, &(q)->queue_flags)
 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
-- 
2.43.0