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mm, hmm: replace hmm_devmem_pages_create() with devm_memremap_pages()
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Commit e8d5134 ("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 ab1b597 "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 7138970
("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>
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Dan Williams authored and Linus Torvalds committed Dec 28, 2018
1 parent 58ef15b commit bbecd94
Showing 1 changed file with 26 additions and 170 deletions.
196 changes: 26 additions & 170 deletions mm/hmm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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
*
Expand All @@ -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();
Expand Down Expand Up @@ -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);
Expand All @@ -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)
Expand Down Expand Up @@ -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);
Expand Down

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