dax: remove the DAXDEV_F_SYNC flag

Remove the DAXDEV_F_SYNC flag and thus the flags argument to alloc_dax and
just let the drivers call set_dax_synchronous directly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NPankaj Gupta <pankaj.gupta@ionos.com>
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20211215084508.435401-4-hch@lst.deSigned-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dax/bus.c

@@ -1324,11 +1324,12 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
 	 * No dax_operations since there is no access to this device outside of
 	 * mmap of the resulting character device.
 	 */
-	dax_dev = alloc_dax(dev_dax, NULL, DAXDEV_F_SYNC);
+	dax_dev = alloc_dax(dev_dax, NULL);
 	if (IS_ERR(dax_dev)) {
 		rc = PTR_ERR(dax_dev);
 		goto err_alloc_dax;
 	}
+	set_dax_synchronous(dax_dev);
 
 	/* a device_dax instance is dead while the driver is not attached */
 	kill_dax(dax_dev);

drivers/dax/super.c

@@ -345,8 +345,7 @@ static struct dax_device *dax_dev_get(dev_t devt)
 	return dax_dev;
 }
 
-struct dax_device *alloc_dax(void *private, const struct dax_operations *ops,
-		unsigned long flags)
+struct dax_device *alloc_dax(void *private, const struct dax_operations *ops)
 {
 	struct dax_device *dax_dev;
 	dev_t devt;
@@ -366,9 +365,6 @@ struct dax_device *alloc_dax(void *private, const struct dax_operations *ops,
 
 	dax_dev->ops = ops;
 	dax_dev->private = private;
-	if (flags & DAXDEV_F_SYNC)
-		set_dax_synchronous(dax_dev);
-
 	return dax_dev;
 
  err_dev:

drivers/md/dm.c

@@ -1765,7 +1765,7 @@ static struct mapped_device *alloc_dev(int minor)
 	sprintf(md->disk->disk_name, "dm-%d", minor);
 
 	if (IS_ENABLED(CONFIG_FS_DAX)) {
-		md->dax_dev = alloc_dax(md, &dm_dax_ops, 0);
+		md->dax_dev = alloc_dax(md, &dm_dax_ops);
 		if (IS_ERR(md->dax_dev)) {
 			md->dax_dev = NULL;
 			goto bad;

drivers/nvdimm/pmem.c

@@ -400,7 +400,6 @@ static int pmem_attach_disk(struct device *dev,
 	struct gendisk *disk;
 	void *addr;
 	int rc;
-	unsigned long flags = 0UL;
 
 	pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
 	if (!pmem)
@@ -493,13 +492,13 @@ static int pmem_attach_disk(struct device *dev,
 	nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_range);
 	disk->bb = &pmem->bb;
 
-	if (is_nvdimm_sync(nd_region))
-		flags = DAXDEV_F_SYNC;
-	dax_dev = alloc_dax(pmem, &pmem_dax_ops, flags);
+	dax_dev = alloc_dax(pmem, &pmem_dax_ops);
 	if (IS_ERR(dax_dev)) {
 		rc = PTR_ERR(dax_dev);
 		goto out;
 	}
+	if (is_nvdimm_sync(nd_region))
+		set_dax_synchronous(dax_dev);
 	rc = dax_add_host(dax_dev, disk);
 	if (rc)
 		goto out_cleanup_dax;

drivers/s390/block/dcssblk.c

@@ -686,13 +686,13 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
 	if (rc)
 		goto put_dev;
 
-	dev_info->dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops,
-			DAXDEV_F_SYNC);
+	dev_info->dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops);
 	if (IS_ERR(dev_info->dax_dev)) {
 		rc = PTR_ERR(dev_info->dax_dev);
 		dev_info->dax_dev = NULL;
 		goto put_dev;
 	}
+	set_dax_synchronous(dev_info->dax_dev);
 	rc = dax_add_host(dev_info->dax_dev, dev_info->gd);
 	if (rc)
 		goto out_dax;

fs/fuse/virtio_fs.c

@@ -850,7 +850,7 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
 	dev_dbg(&vdev->dev, "%s: window kaddr 0x%px phys_addr 0x%llx len 0x%llx\n",
 		__func__, fs->window_kaddr, cache_reg.addr, cache_reg.len);
 
-	fs->dax_dev = alloc_dax(fs, &virtio_fs_dax_ops, 0);
+	fs->dax_dev = alloc_dax(fs, &virtio_fs_dax_ops);
 	if (IS_ERR(fs->dax_dev))
 		return PTR_ERR(fs->dax_dev);
 

include/linux/dax.h

@@ -6,9 +6,6 @@
 #include <linux/mm.h>
 #include <linux/radix-tree.h>
 
-/* Flag for synchronous flush */
-#define DAXDEV_F_SYNC (1UL << 0)
-
 typedef unsigned long dax_entry_t;
 
 struct dax_device;
@@ -42,8 +39,7 @@ struct dax_operations {
 };
 
 #if IS_ENABLED(CONFIG_DAX)
-struct dax_device *alloc_dax(void *private, const struct dax_operations *ops,
-		unsigned long flags);
+struct dax_device *alloc_dax(void *private, const struct dax_operations *ops);
 void put_dax(struct dax_device *dax_dev);
 void kill_dax(struct dax_device *dax_dev);
 void dax_write_cache(struct dax_device *dax_dev, bool wc);
@@ -64,7 +60,7 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
 }
 #else
 static inline struct dax_device *alloc_dax(void *private,
-		const struct dax_operations *ops, unsigned long flags)
+		const struct dax_operations *ops)
 {
 	/*
 	 * Callers should check IS_ENABLED(CONFIG_DAX) to know if this