From: Dan Williams <dan.j.williams@intel.com>
Date: Thu, 31 Mar 2016 22:41:18 +0000 (-0700)
Subject: libnvdimm, dax: record the specified alignment of a dax-device instance
X-Git-Tag: v4.6.7~56
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a093d23c14cd9646993bd7f05c5afcccdb6d3f40;p=thirdparty%2Fkernel%2Fstable.git

libnvdimm, dax: record the specified alignment of a dax-device instance

commit 45a0dac0451136fa7ae34a6fea53ef6a136287ce upstream.

We want to use the alignment as the allocation and mapping unit.
Previously this information was only useful for establishing the data
offset, but now it is important to remember the granularity for the
later use.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h
index 8e343a3ca8730..9d2704c83fa74 100644
--- a/drivers/nvdimm/pfn.h
+++ b/drivers/nvdimm/pfn.h
@@ -33,7 +33,9 @@ struct nd_pfn_sb {
 	/* minor-version-1 additions for section alignment */
 	__le32 start_pad;
 	__le32 end_trunc;
-	u8 padding[4004];
+	/* minor-version-2 record the base alignment of the mapping */
+	__le32 align;
+	u8 padding[4000];
 	__le64 checksum;
 };
 
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index e071e214febad..58bf68c9c414a 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -360,6 +360,9 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn)
 		pfn_sb->end_trunc = 0;
 	}
 
+	if (__le16_to_cpu(pfn_sb->version_minor) < 2)
+		pfn_sb->align = 0;
+
 	switch (le32_to_cpu(pfn_sb->mode)) {
 	case PFN_MODE_RAM:
 	case PFN_MODE_PMEM:
@@ -399,7 +402,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn)
 		return -EBUSY;
 	}
 
-	nd_pfn->align = 1UL << ilog2(offset);
+	nd_pfn->align = le32_to_cpu(pfn_sb->align);
 	if (!is_power_of_2(offset) || offset < PAGE_SIZE) {
 		dev_err(&nd_pfn->dev, "bad offset: %#llx dax disabled\n",
 				offset);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 92f536596b242..58ad81dcd1a5c 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -426,9 +426,10 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 	memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 	memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 	pfn_sb->version_major = cpu_to_le16(1);
-	pfn_sb->version_minor = cpu_to_le16(1);
+	pfn_sb->version_minor = cpu_to_le16(2);
 	pfn_sb->start_pad = cpu_to_le32(start_pad);
 	pfn_sb->end_trunc = cpu_to_le32(end_trunc);
+	pfn_sb->align = cpu_to_le32(nd_pfn->align);
 	checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 	pfn_sb->checksum = cpu_to_le64(checksum);