Patch "libnvdimm, pfn: fix start_pad handling for aligned namespaces" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

libnvdimm, pfn: fix start_pad handling for aligned namespaces

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
libnvdimm-pfn-fix-start_pad-handling-for-aligned-namespaces.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dan Williams <[email protected]>
Date: Tue, 19 Dec 2017 15:07:10 -0800
Subject: libnvdimm, pfn: fix start_pad handling for aligned namespaces

From: Dan Williams <[email protected]>

commit 19deaa217bc04e83b59b5e8c8229eb0e53ad9efc upstream.

The alignment checks at pfn driver startup fail to properly account for the 'start_pad' in the case where the namespace is misaligned relative to its internal alignment. This is typically triggered in 1G aligned namespace, but could theoretically trigger with small namespace alignments. When this triggers the kernel reports messages of the form:

    dax2.1: bad offset: 0x3c000000 dax disabled align: 0x40000000

---
 drivers/nvdimm/pfn_devs.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

@@ -352,9 +352,9 @@ struct device *nd_pfn_create(struct nd_r
 int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 {
 	u64 checksum, offset;
-	unsigned long align;
 	enum nd_pfn_mode mode;
 	struct nd_namespace_io *nsio;
+	unsigned long align, start_pad;
 	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 	struct nd_namespace_common *ndns = nd_pfn->ndns;
 	const u8 *parent_uuid = nd_dev_to_uuid(&ndns->dev);

@@ -398,6 +398,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pf
 
 	align = le32_to_cpu(pfn_sb->align);
 	offset = le64_to_cpu(pfn_sb->dataoff);
+	start_pad = le32_to_cpu(pfn_sb->start_pad);
 	if (align == 0)
 		align = 1UL << ilog2(offset);
 	mode = le32_to_cpu(pfn_sb->mode);

@@ -456,7 +457,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pf
 		return -EBUSY;
 	}
 
-	if ((align && !IS_ALIGNED(offset, align))
+	if ((align && !IS_ALIGNED(nsio->res.start + offset + start_pad, align))
 			|| !IS_ALIGNED(offset, PAGE_SIZE)) {
 		dev_err(&nd_pfn->dev,
 				"bad offset: %#llx dax disabled align: %#lx\n",

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/libnvdimm-pfn-fix-start_pad-handling-for-aligned-namespaces.patch queue-4.9/libnvdimm-dax-fix-1gb-aligned-namespaces-vs-physical-misalignment.patch queue-4.9/acpi-nfit-fix-health-event-notification.patch