[PATCH 3/6] mm/hmm: add new helper to hotplug CDM memory region v3

[Jérôme Glisse]

Unlike unaddressable memory, coherent device memory has a real
resource associated with it on the system (as CPU can address
it). Add a new helper to hotplug such memory within the HMM
framework.

Changed since v2:
  - s/host/public
Changed since v1:
  - s/public/host

Signed-off-by: Jérôme Glisse 
Reviewed-by: Balbir Singh 
---
 include/linux/hmm.h |  3 ++
 mm/hmm.c| 85 +
 2 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index a40288309fd2..e44cb8edb137 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -392,6 +392,9 @@ struct hmm_devmem {
 struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
  struct device *device,
  unsigned long size);
+struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
+  struct device *device,
+  struct resource *res);
 void hmm_devmem_remove(struct hmm_devmem *devmem);
 
 /*
diff --git a/mm/hmm.c b/mm/hmm.c
index eadf70829c34..28e54e3b4e1d 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -849,7 +849,11 @@ static void hmm_devmem_release(struct device *dev, void 
*data)
zone = page_zone(page);
 
mem_hotplug_begin();
-   __remove_pages(zone, start_pfn, npages);
+   if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY)
+   __remove_pages(zone, start_pfn, npages);
+   else
+   arch_remove_memory(start_pfn << PAGE_SHIFT,
+  npages << PAGE_SHIFT);
mem_hotplug_done();
 
hmm_devmem_radix_release(resource);
@@ -885,7 +889,11 @@ static int hmm_devmem_pages_create(struct hmm_devmem 
*devmem)
if (is_ram == REGION_INTERSECTS)
return -ENXIO;
 
-   devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+   if (devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY)
+   devmem->pagemap.type = MEMORY_DEVICE_PUBLIC;
+   else
+   devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+
devmem->pagemap.res = devmem->resource;
devmem->pagemap.page_fault = hmm_devmem_fault;
devmem->pagemap.page_free = hmm_devmem_free;
@@ -924,8 +932,11 @@ static int hmm_devmem_pages_create(struct hmm_devmem 
*devmem)
nid = numa_mem_id();
 
mem_hotplug_begin();
-   ret = add_pages(nid, align_start >> PAGE_SHIFT,
-   align_size >> PAGE_SHIFT, false);
+   if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC)
+   ret = arch_add_memory(nid, align_start, align_size, false);
+   else
+   ret = add_pages(nid, align_start >> PAGE_SHIFT,
+   align_size >> PAGE_SHIFT, false);
if (ret) {
mem_hotplug_done();
goto error_add_memory;
@@ -1075,6 +1086,67 @@ struct hmm_devmem *hmm_devmem_add(const struct 
hmm_devmem_ops *ops,
 }
 EXPORT_SYMBOL(hmm_devmem_add);
 
+struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
+  struct device *device,
+  struct resource *res)
+{
+   struct hmm_devmem *devmem;
+   int ret;
+
+   if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY)
+   return ERR_PTR(-EINVAL);
+
+   static_branch_enable(_private_key);
+
+   devmem = devres_alloc_node(_devmem_release, sizeof(*devmem),
+  GFP_KERNEL, dev_to_node(device));
+   if (!devmem)
+   return ERR_PTR(-ENOMEM);
+
+   init_completion(>completion);
+   devmem->pfn_first = -1UL;
+   devmem->pfn_last = -1UL;
+   devmem->resource = res;
+   devmem->device = device;
+   devmem->ops = ops;
+
+   ret = percpu_ref_init(>ref, _devmem_ref_release,
+ 0, GFP_KERNEL);
+   if (ret)
+   goto error_percpu_ref;
+
+   ret = devm_add_action(device, hmm_devmem_ref_exit, >ref);
+   if (ret)
+   goto error_devm_add_action;
+
+
+   devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
+   devmem->pfn_last = devmem->pfn_first +
+  (resource_size(devmem->resource) >> PAGE_SHIFT);
+
+   ret = hmm_devmem_pages_create(devmem);
+   if (ret)
+   goto error_devm_add_action;
+
+   devres_add(device, devmem);
+
+   ret = devm_add_action(device, hmm_devmem_ref_kill, >ref);
+   if (ret) {
+   hmm_devmem_remove(devmem);
+   return ERR_PTR(ret);
+   }
+
+   return devmem;
+
+error_devm_add_action:
+   hmm_devmem_ref_kill(>ref);
+   hmm_devmem_ref_exit(>ref);
+error_percpu_ref:
+   devres_free(devmem);
+   return ERR_PTR(ret);
+}

[PATCH 3/6] mm/hmm: add new helper to hotplug CDM memory region v3

[Jérôme Glisse]

Unlike unaddressable memory, coherent device memory has a real
resource associated with it on the system (as CPU can address
it). Add a new helper to hotplug such memory within the HMM
framework.

Changed since v2:
  - s/host/public
Changed since v1:
  - s/public/host

Signed-off-by: Jérôme Glisse 
Reviewed-by: Balbir Singh 
---
 include/linux/hmm.h |  3 ++
 mm/hmm.c| 85 +
 2 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index a40288309fd2..e44cb8edb137 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -392,6 +392,9 @@ struct hmm_devmem {
 struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
  struct device *device,
  unsigned long size);
+struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
+  struct device *device,
+  struct resource *res);
 void hmm_devmem_remove(struct hmm_devmem *devmem);
 
 /*
diff --git a/mm/hmm.c b/mm/hmm.c
index eadf70829c34..28e54e3b4e1d 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -849,7 +849,11 @@ static void hmm_devmem_release(struct device *dev, void 
*data)
zone = page_zone(page);
 
mem_hotplug_begin();
-   __remove_pages(zone, start_pfn, npages);
+   if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY)
+   __remove_pages(zone, start_pfn, npages);
+   else
+   arch_remove_memory(start_pfn << PAGE_SHIFT,
+  npages << PAGE_SHIFT);
mem_hotplug_done();
 
hmm_devmem_radix_release(resource);
@@ -885,7 +889,11 @@ static int hmm_devmem_pages_create(struct hmm_devmem 
*devmem)
if (is_ram == REGION_INTERSECTS)
return -ENXIO;
 
-   devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+   if (devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY)
+   devmem->pagemap.type = MEMORY_DEVICE_PUBLIC;
+   else
+   devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
+
devmem->pagemap.res = devmem->resource;
devmem->pagemap.page_fault = hmm_devmem_fault;
devmem->pagemap.page_free = hmm_devmem_free;
@@ -924,8 +932,11 @@ static int hmm_devmem_pages_create(struct hmm_devmem 
*devmem)
nid = numa_mem_id();
 
mem_hotplug_begin();
-   ret = add_pages(nid, align_start >> PAGE_SHIFT,
-   align_size >> PAGE_SHIFT, false);
+   if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC)
+   ret = arch_add_memory(nid, align_start, align_size, false);
+   else
+   ret = add_pages(nid, align_start >> PAGE_SHIFT,
+   align_size >> PAGE_SHIFT, false);
if (ret) {
mem_hotplug_done();
goto error_add_memory;
@@ -1075,6 +1086,67 @@ struct hmm_devmem *hmm_devmem_add(const struct 
hmm_devmem_ops *ops,
 }
 EXPORT_SYMBOL(hmm_devmem_add);
 
+struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
+  struct device *device,
+  struct resource *res)
+{
+   struct hmm_devmem *devmem;
+   int ret;
+
+   if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY)
+   return ERR_PTR(-EINVAL);
+
+   static_branch_enable(_private_key);
+
+   devmem = devres_alloc_node(_devmem_release, sizeof(*devmem),
+  GFP_KERNEL, dev_to_node(device));
+   if (!devmem)
+   return ERR_PTR(-ENOMEM);
+
+   init_completion(>completion);
+   devmem->pfn_first = -1UL;
+   devmem->pfn_last = -1UL;
+   devmem->resource = res;
+   devmem->device = device;
+   devmem->ops = ops;
+
+   ret = percpu_ref_init(>ref, _devmem_ref_release,
+ 0, GFP_KERNEL);
+   if (ret)
+   goto error_percpu_ref;
+
+   ret = devm_add_action(device, hmm_devmem_ref_exit, >ref);
+   if (ret)
+   goto error_devm_add_action;
+
+
+   devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
+   devmem->pfn_last = devmem->pfn_first +
+  (resource_size(devmem->resource) >> PAGE_SHIFT);
+
+   ret = hmm_devmem_pages_create(devmem);
+   if (ret)
+   goto error_devm_add_action;
+
+   devres_add(device, devmem);
+
+   ret = devm_add_action(device, hmm_devmem_ref_kill, >ref);
+   if (ret) {
+   hmm_devmem_remove(devmem);
+   return ERR_PTR(ret);
+   }
+
+   return devmem;
+
+error_devm_add_action:
+   hmm_devmem_ref_kill(>ref);
+   hmm_devmem_ref_exit(>ref);
+error_percpu_ref:
+   devres_free(devmem);
+   return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(hmm_devmem_add_resource);
+
 /*
  * hmm_devmem_remove() - remove