[PATCH V3 3/9] dax/fsdev: clear vmemmap_shift when binding static pgmap

[John Groves]

From: John Groves <j...@groves.net>

Clear pgmap->vmemmap_shift for static DAX devices. When rebinding a static
device from device_dax (which may set vmemmap_shift based on alignment) to
fsdev_dax, the stale vmemmap_shift persists on the shared pgmap. Explicitly
zero it before devm_memremap_pages() so the vmemmap is built for order-0
folios as fsdev requires.

Fixes: d5406bd458b0a ("dax: add fsdev.c driver for fs-dax on character dax")
Signed-off-by: John Groves <j...@groves.net>
---
 drivers/dax/fsdev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/dax/fsdev.c b/drivers/dax/fsdev.c
index f315533b299e9..dbd722ed7ab05 100644
--- a/drivers/dax/fsdev.c
+++ b/drivers/dax/fsdev.c
@@ -237,6 +237,7 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
                }
 
                pgmap = dev_dax->pgmap;
+               pgmap->vmemmap_shift = 0;
        } else {
                size_t pgmap_size;
 
-- 
2.53.0