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Subject[PATCH v5 02/17] device-dax/kmem: introduce dax_kmem_range()
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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.

Cc: David Hildenbrand <david@redhat.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jia He <justin.he@arm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/dax/kmem.c | 40 +++++++++++++++++-----------------------
1 file changed, 17 insertions(+), 23 deletions(-)

diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 5bb133df147d..b0d6a99cf12d 100644
--- a/drivers/dax/kmem.c
+++ b/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 *dev)
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 *dev)
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 device *dev)
* 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;
}

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