From d9d290d7e659e9db3e4518040cc18b97f5535f4a Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Wed, 9 Mar 2022 19:49:21 -0800
Subject: [PATCH] nvdimm/region: Fix default alignment for small regions
Git-commit: d9d290d7e659e9db3e4518040cc18b97f5535f4a
Patch-mainline: v5.18-rc1
References: jsc#PED-1689, jsc#PED-1690
In preparation for removing BLK aperture support the NVDIMM unit tests
discovered that the default alignment can be set higher than the
capacity of the region. Fall back to PAGE_SIZE in that case.
Given this has not been seen in the wild, elide notifying -stable.
Fixes: 2522afb86a8c ("libnvdimm/region: Introduce an 'align' attribute")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/164688416128.2879318.17890707310125575258.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Coly Li <colyli@suse.de>
---
drivers/nvdimm/region_devs.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 9ccf3d608799..70ad891a76ba 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1025,6 +1025,9 @@ static unsigned long default_align(struct nd_region *nd_region)
}
}
+ if (nd_region->ndr_size < MEMREMAP_COMPAT_ALIGN_MAX)
+ align = PAGE_SIZE;
+
mappings = max_t(u16, 1, nd_region->ndr_mappings);
div_u64_rem(align, mappings, &remainder);
if (remainder)
--
2.35.3