From: Dan Williams dan.j.williams@intel.com Subject: mm, hmm: replace hmm_devmem_pages_create() with devm_memremap_pages()

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@dwill... 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 ---

--- a/mm/hmm.c~mm-hmm-replace-hmm_devmem_pages_create-with-devm_memremap_pages +++ a/mm/hmm.c @@ -986,17 +986,16 @@ static void hmm_devmem_ref_exit(void *da 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 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 *devmem; resource_size_t addr; + void *result; int ret;

dev_pagemap_get_ops(); @@ -1244,14 +1096,18 @@ struct hmm_devmem *hmm_devmem_add(const 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_resour 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_resour 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); _