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SubjectRe: [PATCH v5 02/17] device-dax/kmem: introduce dax_kmem_range()
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On 25.09.20 21:11, Dan Williams wrote:
> 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;
> }
>
>

Reviewed-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb

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