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memremap: change devm_memremap_pages interface to use struct dev_pagemap

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This new interface is similar to how struct device (and many others)
work. The caller initializes a 'struct dev_pagemap' as required
and calls 'devm_memremap_pages'. This allows the pagemap structure to
be embedded in another structure and thus container_of can be used. In
this way application specific members can be stored in a containing
struct.

This will be used by the P2P infrastructure and HMM could probably
be cleaned up to use it as well (instead of having it's own, similar
'hmm_devmem_pages_create' function).

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Christoph Hellwig
2017-12-29 08:54:05 +01:00
committed by Dan Williams
parent e7744aa25c
commit e8d5134833
8 changed files with 81 additions and 85 deletions
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51
kernel/memremap.c
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@@ -275,9 +275,10 @@ static unsigned long pfn_end(struct dev_pagemap *pgmap)
#define for_each_device_pfn(pfn, map) \
for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++)
static void devm_memremap_pages_release(struct device *dev, void *data)
static void devm_memremap_pages_release(void *data)
{
struct dev_pagemap *pgmap = data;
struct device *dev = pgmap->dev;
struct resource *res = &pgmap->res;
resource_size_t align_start, align_size;
unsigned long pfn;
@@ -316,29 +317,34 @@ static struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
/**
* devm_memremap_pages - remap and provide memmap backing for the given resource
* @dev: hosting device for @res
* @res: "host memory" address range
* @ref: a live per-cpu reference count
* @altmap: optional descriptor for allocating the memmap from @res
* @pgmap: pointer to a struct dev_pgmap
*
* Notes:
* 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
* (or devm release event). The expected order of events is that @ref has
* 1/ At a minimum the res, ref and type members of @pgmap must be initialized
* by the caller before passing it to this function
*
* 2/ The altmap field may optionally be initialized, in which case altmap_valid
* must be set to true
*
* 3/ pgmap.ref must be 'live' on entry and 'dead' before devm_memunmap_pages()
* time (or devm release event). The expected order of events is that ref has
* been through percpu_ref_kill() before devm_memremap_pages_release(). The
* wait for the completion of all references being dropped and
* percpu_ref_exit() must occur after devm_memremap_pages_release().
*
* 2/ @res is expected to be a host memory range that could feasibly be
* 4/ res is expected to be a host memory range that could feasibly be
* treated as a "System RAM" range, i.e. not a device mmio range, but
* this is not enforced.
*/
void *devm_memremap_pages(struct device *dev, struct resource *res,
struct percpu_ref *ref, struct vmem_altmap *altmap)
void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
{
resource_size_t align_start, align_size, align_end;
struct vmem_altmap *altmap = pgmap->altmap_valid ?
&pgmap->altmap : NULL;
unsigned long pfn, pgoff, order;
pgprot_t pgprot = PAGE_KERNEL;
struct dev_pagemap *pgmap;
int error, nid, is_ram, i = 0;
struct resource *res = &pgmap->res;
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
@@ -355,27 +361,10 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
if (is_ram == REGION_INTERSECTS)
return __va(res->start);
if (!ref)
if (!pgmap->ref)
return ERR_PTR(-EINVAL);
pgmap = devres_alloc_node(devm_memremap_pages_release,
sizeof(*pgmap), GFP_KERNEL, dev_to_node(dev));
if (!pgmap)
return ERR_PTR(-ENOMEM);
memcpy(&pgmap->res, res, sizeof(*res));
pgmap->dev = dev;
if (altmap) {
memcpy(&pgmap->altmap, altmap, sizeof(*altmap));
pgmap->altmap_valid = true;
altmap = &pgmap->altmap;
}
pgmap->ref = ref;
pgmap->type = MEMORY_DEVICE_HOST;
pgmap->page_fault = NULL;
pgmap->page_free = NULL;
pgmap->data = NULL;
mutex_lock(&pgmap_lock);
error = 0;
@@ -423,11 +412,13 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
*/
list_del(&page->lru);
page->pgmap = pgmap;
percpu_ref_get(ref);
percpu_ref_get(pgmap->ref);
if (!(++i % 1024))
cond_resched();
}
devres_add(dev, pgmap);
devm_add_action(dev, devm_memremap_pages_release, pgmap);
return __va(res->start);
err_add_memory: