mm, hmm: replace hmm_devmem_pages_create() with devm_memremap_pages()

Commit e8d513483300 ("memremap: change devm_memremap_pages interface to
use struct dev_pagemap") refactored devm_memremap_pages() to allow a
dev_pagemap instance to be supplied.  Passing in a dev_pagemap interface
simplifies the design of pgmap type drivers in that they can rely on
container_of() to lookup any private data associated with the given
dev_pagemap instance.

In addition to the cleanups this also gives hmm users multi-order-radix
improvements that arrived with commit ab1b597ee0e4 "mm,
devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups"

As part of the conversion to the devm_memremap_pages() method of
handling the percpu_ref relative to when pages are put, the percpu_ref
completion needs to move to hmm_devmem_ref_exit().  See 71389703839e
("mm, zone_device: Replace {get, put}_zone_device_page...") for details.

Link: http://lkml.kernel.org/r/154275560053.76910.10870962637383152392.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/hmm.c b/mm/hmm.c
index 8510881e7b44da4b6ebac9cb12e1668b4c8c227f..bf2495d9de81bf8ae1e4fd7ae5d376ce8820045e 100644 (file)
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -986,17 +986,16 @@ static void hmm_devmem_ref_exit(void *data)
        struct hmm_devmem *devmem;
 
        devmem = container_of(ref, struct hmm_devmem, ref);
+       wait_for_completion(&devmem->completion);
        percpu_ref_exit(ref);
 }
 
-static void hmm_devmem_ref_kill(void *data)
+static void hmm_devmem_ref_kill(struct percpu_ref *ref)
 {
-       struct percpu_ref *ref = data;
        struct hmm_devmem *devmem;
 
        devmem = container_of(ref, struct hmm_devmem, ref);
        percpu_ref_kill(ref);
-       wait_for_completion(&devmem->completion);
 }
 
 static int hmm_devmem_fault(struct vm_area_struct *vma,
@@ -1019,154 +1018,6 @@ static void hmm_devmem_free(struct page *page, void *data)
        devmem->ops->free(devmem, page);
 }
 
-static DEFINE_MUTEX(hmm_devmem_lock);
-static RADIX_TREE(hmm_devmem_radix, GFP_KERNEL);
-
-static void hmm_devmem_radix_release(struct resource *resource)
-{
-       resource_size_t key;
-
-       mutex_lock(&hmm_devmem_lock);
-       for (key = resource->start;
-            key <= resource->end;
-            key += PA_SECTION_SIZE)
-               radix_tree_delete(&hmm_devmem_radix, key >> PA_SECTION_SHIFT);
-       mutex_unlock(&hmm_devmem_lock);
-}
-
-static void hmm_devmem_release(void *data)
-{
-       struct hmm_devmem *devmem = data;
-       struct resource *resource = devmem->resource;
-       unsigned long start_pfn, npages;
-       struct zone *zone;
-       struct page *page;
-
-       /* pages are dead and unused, undo the arch mapping */
-       start_pfn = (resource->start & ~(PA_SECTION_SIZE - 1)) >> PAGE_SHIFT;
-       npages = ALIGN(resource_size(resource), PA_SECTION_SIZE) >> PAGE_SHIFT;
-
-       page = pfn_to_page(start_pfn);
-       zone = page_zone(page);
-
-       mem_hotplug_begin();
-       if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY)
-               __remove_pages(zone, start_pfn, npages, NULL);
-       else
-               arch_remove_memory(start_pfn << PAGE_SHIFT,
-                                  npages << PAGE_SHIFT, NULL);
-       mem_hotplug_done();
-
-       hmm_devmem_radix_release(resource);
-}
-
-static int hmm_devmem_pages_create(struct hmm_devmem *devmem)
-{
-       resource_size_t key, align_start, align_size, align_end;
-       struct device *device = devmem->device;
-       int ret, nid, is_ram;
-
-       align_start = devmem->resource->start & ~(PA_SECTION_SIZE - 1);
-       align_size = ALIGN(devmem->resource->start +
-                          resource_size(devmem->resource),
-                          PA_SECTION_SIZE) - align_start;
-
-       is_ram = region_intersects(align_start, align_size,
-                                  IORESOURCE_SYSTEM_RAM,
-                                  IORES_DESC_NONE);
-       if (is_ram == REGION_MIXED) {
-               WARN_ONCE(1, "%s attempted on mixed region %pr\n",
-                               __func__, devmem->resource);
-               return -ENXIO;
-       }
-       if (is_ram == REGION_INTERSECTS)
-               return -ENXIO;
-
-       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;
-       devmem->pagemap.dev = devmem->device;
-       devmem->pagemap.ref = &devmem->ref;
-       devmem->pagemap.data = devmem;
-
-       mutex_lock(&hmm_devmem_lock);
-       align_end = align_start + align_size - 1;
-       for (key = align_start; key <= align_end; key += PA_SECTION_SIZE) {
-               struct hmm_devmem *dup;
-
-               dup = radix_tree_lookup(&hmm_devmem_radix,
-                                       key >> PA_SECTION_SHIFT);
-               if (dup) {
-                       dev_err(device, "%s: collides with mapping for %s\n",
-                               __func__, dev_name(dup->device));
-                       mutex_unlock(&hmm_devmem_lock);
-                       ret = -EBUSY;
-                       goto error;
-               }
-               ret = radix_tree_insert(&hmm_devmem_radix,
-                                       key >> PA_SECTION_SHIFT,
-                                       devmem);
-               if (ret) {
-                       dev_err(device, "%s: failed: %d\n", __func__, ret);
-                       mutex_unlock(&hmm_devmem_lock);
-                       goto error_radix;
-               }
-       }
-       mutex_unlock(&hmm_devmem_lock);
-
-       nid = dev_to_node(device);
-       if (nid < 0)
-               nid = numa_mem_id();
-
-       mem_hotplug_begin();
-       /*
-        * For device private memory we call add_pages() as we only need to
-        * allocate and initialize struct page for the device memory. More-
-        * over the device memory is un-accessible thus we do not want to
-        * create a linear mapping for the memory like arch_add_memory()
-        * would do.
-        *
-        * For device public memory, which is accesible by the CPU, we do
-        * want the linear mapping and thus use arch_add_memory().
-        */
-       if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC)
-               ret = arch_add_memory(nid, align_start, align_size, NULL,
-                               false);
-       else
-               ret = add_pages(nid, align_start >> PAGE_SHIFT,
-                               align_size >> PAGE_SHIFT, NULL, false);
-       if (ret) {
-               mem_hotplug_done();
-               goto error_add_memory;
-       }
-       move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
-                               align_start >> PAGE_SHIFT,
-                               align_size >> PAGE_SHIFT, NULL);
-       mem_hotplug_done();
-
-       /*
-        * Initialization of the pages has been deferred until now in order
-        * to allow us to do the work while not holding the hotplug lock.
-        */
-       memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
-                               align_start >> PAGE_SHIFT,
-                               align_size >> PAGE_SHIFT, &devmem->pagemap);
-
-       return 0;
-
-error_add_memory:
-       untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
-error_radix:
-       hmm_devmem_radix_release(devmem->resource);
-error:
-       return ret;
-}
-
 /*
  * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory
  *
@@ -1190,6 +1041,7 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
 {
        struct hmm_devmem *devmem;
        resource_size_t addr;
+       void *result;
        int ret;
 
        dev_pagemap_get_ops();
@@ -1244,14 +1096,18 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
        devmem->pfn_last = devmem->pfn_first +
                           (resource_size(devmem->resource) >> PAGE_SHIFT);
 
-       ret = hmm_devmem_pages_create(devmem);
-       if (ret)
-               return ERR_PTR(ret);
-
-       ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem);
-       if (ret)
-               return ERR_PTR(ret);
+       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;
+       devmem->pagemap.altmap_valid = false;
+       devmem->pagemap.ref = &devmem->ref;
+       devmem->pagemap.data = devmem;
+       devmem->pagemap.kill = hmm_devmem_ref_kill;
 
+       result = devm_memremap_pages(devmem->device, &devmem->pagemap);
+       if (IS_ERR(result))
+               return result;
        return devmem;
 }
 EXPORT_SYMBOL(hmm_devmem_add);
@@ -1261,6 +1117,7 @@ struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
                                           struct resource *res)
 {
        struct hmm_devmem *devmem;
+       void *result;
        int ret;
 
        if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY)
@@ -1293,19 +1150,18 @@ struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
        devmem->pfn_last = devmem->pfn_first +
                           (resource_size(devmem->resource) >> PAGE_SHIFT);
 
-       ret = hmm_devmem_pages_create(devmem);
-       if (ret)
-               return ERR_PTR(ret);
-
-       ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem);
-       if (ret)
-               return ERR_PTR(ret);
-
-       ret = devm_add_action_or_reset(device, hmm_devmem_ref_kill,
-                       &devmem->ref);
-       if (ret)
-               return ERR_PTR(ret);
+       devmem->pagemap.type = MEMORY_DEVICE_PUBLIC;
+       devmem->pagemap.res = *devmem->resource;
+       devmem->pagemap.page_fault = hmm_devmem_fault;
+       devmem->pagemap.page_free = hmm_devmem_free;
+       devmem->pagemap.altmap_valid = false;
+       devmem->pagemap.ref = &devmem->ref;
+       devmem->pagemap.data = devmem;
+       devmem->pagemap.kill = hmm_devmem_ref_kill;
 
+       result = devm_memremap_pages(devmem->device, &devmem->pagemap);
+       if (IS_ERR(result))
+               return result;
        return devmem;
 }
 EXPORT_SYMBOL(hmm_devmem_add_resource);