linux-kernel - [PATCH 3/3] libnvdimm, pfn, dax: limit namespace alignments to the supported set

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Date:   Fri, 11 Aug 2017 22:12:33 -0700
From:   Dan Williams <dan.j.williams@...el.com>
To:     linux-nvdimm@...ts.01.org
Cc:     Oliver O'Halloran <oohall@...il.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] libnvdimm, pfn,
 dax: limit namespace alignments to the supported set

Now that we properly advertise the supported pte, pmd, and pud sizes,
restrict the supported alignments that can be set on a namespace. This
assumes that userspace was not previously relying on the ability to set
odd alignments. At least ndctl only ever supported setting the namespace
alignment to 4K, 2M, or 1G.

Cc: Oliver O'Halloran <oohall@...il.com>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
 drivers/nvdimm/pfn_devs.c |   23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 610dd17a17f6..f447a1eb919d 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -131,26 +131,6 @@ static const unsigned long *nd_pfn_supported_alignments(void)
 	return supported_alignments;
 }
 
-static ssize_t __align_store(struct nd_pfn *nd_pfn, const char *buf)
-{
-	unsigned long val;
-	int rc;
-
-	rc = kstrtoul(buf, 0, &val);
-	if (rc)
-		return rc;
-
-	if (!is_power_of_2(val) || val < PAGE_SIZE || val > SZ_1G)
-		return -EINVAL;
-
-	if (nd_pfn->dev.driver)
-		return -EBUSY;
-	else
-		nd_pfn->align = val;
-
-	return 0;
-}
-
 static ssize_t align_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
@@ -159,7 +139,8 @@ static ssize_t align_store(struct device *dev,
 
 	device_lock(dev);
 	nvdimm_bus_lock(dev);
-	rc = __align_store(nd_pfn, buf);
+	rc = nd_size_select_store(dev, buf, &nd_pfn->align,
+			nd_pfn_supported_alignments());
 	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 			rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 	nvdimm_bus_unlock(dev);