[PATCH v3 3/3] dax: temporarily disable DAX PMD fault path

There is currently a deadlock in the DAX PMD fault path because it ends up taking the same mapping->i_mmap_rwsem twice. The first take is a i_mmap_lock_read() near the beginning of __dax_pmd_fault(), and the second is __dax_pmd_fault() -> unmap_mapping_range() -> i_mmap_lock_write(). We are

[PATCH v3 3/3] dax: temporarily disable DAX PMD fault path

There is currently a deadlock in the DAX PMD fault path because it ends up taking the same mapping->i_mmap_rwsem twice. The first take is a i_mmap_lock_read() near the beginning of __dax_pmd_fault(), and the second is __dax_pmd_fault() -> unmap_mapping_range() -> i_mmap_lock_write(). We are