[036/181] device-dax/kmem: introduce dax_kmem_range()

Commit Message

Andrew Morton Oct. 13, 2020, 11:49 p.m. UTC

From: Dan Williams <[e-mail]>
Subject: device-dax/kmem: introduce dax_kmem_range()

Towards removing the mode specific @dax_kmem_res attribute from the
generic 'struct dev_dax', and preparing for multi-range support, teach the
driver to calculate the hotplug range from the device range.  The hotplug
range is the trivially calculated memory-block-size aligned version of the
device range.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Dan Williams <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: Vishal Verma <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Pavel Tatashin <[e-mail]>
Cc: Brice Goglin <[e-mail]>
Cc: Dave Jiang <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: Ira Weiny <[e-mail]>
Cc: Jia He <[e-mail]>
Cc: Joao Martins <[e-mail]>
Cc: Jonathan Cameron <[e-mail]>
Cc: Andy Lutomirski <[e-mail]>
Cc: Ard Biesheuvel <[e-mail]>
Cc: Ard Biesheuvel <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Cc: Ben Skeggs <[e-mail]>
Cc: Bjorn Helgaas <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: Boris Ostrovsky <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Cc: Hulk Robot <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jason Gunthorpe <[e-mail]>
Cc: Jason Yan <[e-mail]>
Cc: Jeff Moyer <[e-mail]>
Cc: "Jérôme Glisse" <[e-mail]>
Cc: Juergen Gross <[e-mail]>
Cc: kernel test robot <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Mike Rapoport <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: "Rafael J. Wysocki" <[e-mail]>
Cc: Randy Dunlap <[e-mail]>
Cc: Stefano Stabellini <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tom Lendacky <[e-mail]>
Cc: Vivek Goyal <[e-mail]>
Cc: Wei Yang <[e-mail]>
Cc: Will Deacon <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 drivers/dax/kmem.c |   40 +++++++++++++++++-----------------------
 1 file changed, 17 insertions(+), 23 deletions(-)

Patch

--- a/drivers/dax/kmem.c~device-dax-kmem-introduce-dax_kmem_range
+++ a/drivers/dax/kmem.c
@@ -19,13 +19,20 @@  static const char *kmem_name;
 /* Set if any memory will remain added when the driver will be unloaded. */
 static bool any_hotremove_failed;
 
+static struct range dax_kmem_range(struct dev_dax *dev_dax)
+{
+	struct range range;
+
+	/* memory-block align the hotplug range */
+	range.start = ALIGN(dev_dax->range.start, memory_block_size_bytes());
+	range.end = ALIGN_DOWN(dev_dax->range.end + 1, memory_block_size_bytes()) - 1;
+	return range;
+}
+
 int dev_dax_kmem_probe(struct device *dev)
 {
 	struct dev_dax *dev_dax = to_dev_dax(dev);
-	struct range *range = &dev_dax->range;
-	resource_size_t kmem_start;
-	resource_size_t kmem_size;
-	resource_size_t kmem_end;
+	struct range range = dax_kmem_range(dev_dax);
 	struct resource *new_res;
 	const char *new_res_name;
 	int numa_node;
@@ -44,25 +51,14 @@  int dev_dax_kmem_probe(struct device *de
 		return -EINVAL;
 	}
 
-	/* Hotplug starting at the beginning of the next block: */
-	kmem_start = ALIGN(range->start, memory_block_size_bytes());
-
-	kmem_size = range_len(range);
-	/* Adjust the size down to compensate for moving up kmem_start: */
-	kmem_size -= kmem_start - range->start;
-	/* Align the size down to cover only complete blocks: */
-	kmem_size &= ~(memory_block_size_bytes() - 1);
-	kmem_end = kmem_start + kmem_size;
-
 	new_res_name = kstrdup(dev_name(dev), GFP_KERNEL);
 	if (!new_res_name)
 		return -ENOMEM;
 
 	/* Region is permanently reserved if hotremove fails. */
-	new_res = request_mem_region(kmem_start, kmem_size, new_res_name);
+	new_res = request_mem_region(range.start, range_len(&range), new_res_name);
 	if (!new_res) {
-		dev_warn(dev, "could not reserve region [%pa-%pa]\n",
-			 &kmem_start, &kmem_end);
+		dev_warn(dev, "could not reserve region [%#llx-%#llx]\n", range.start, range.end);
 		kfree(new_res_name);
 		return -EBUSY;
 	}
@@ -96,9 +92,8 @@  int dev_dax_kmem_probe(struct device *de
 static int dev_dax_kmem_remove(struct device *dev)
 {
 	struct dev_dax *dev_dax = to_dev_dax(dev);
+	struct range range = dax_kmem_range(dev_dax);
 	struct resource *res = dev_dax->dax_kmem_res;
-	resource_size_t kmem_start = res->start;
-	resource_size_t kmem_size = resource_size(res);
 	const char *res_name = res->name;
 	int rc;
 
@@ -108,12 +103,11 @@  static int dev_dax_kmem_remove(struct de
 	 * there is no way to hotremove this memory until reboot because device
 	 * unbind will succeed even if we return failure.
 	 */
-	rc = remove_memory(dev_dax->target_node, kmem_start, kmem_size);
+	rc = remove_memory(dev_dax->target_node, range.start, range_len(&range));
 	if (rc) {
 		any_hotremove_failed = true;
-		dev_err(dev,
-			"DAX region %pR cannot be hotremoved until the next reboot\n",
-			res);
+		dev_err(dev, "%#llx-%#llx cannot be hotremoved until the next reboot\n",
+				range.start, range.end);
 		return rc;
 	}