memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag

Add a flags field to struct dev_pagemap to replace the altmap_valid
boolean to be a little more extensible.  Also add a pgmap_altmap() helper
to find the optional altmap and clean up the code using the altmap using
it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/mm/hmm.c b/mm/hmm.c
index 36e25cdbdac1..e4470462298f 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -1442,7 +1442,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
 	devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
 	devmem->pagemap.res = *devmem->resource;
 	devmem->pagemap.ops = &hmm_pagemap_ops;
-	devmem->pagemap.altmap_valid = false;
 	devmem->pagemap.ref = &devmem->ref;
 
 	result = devm_memremap_pages(devmem->device, &devmem->pagemap);