[PATCH 15/17] memremap: drop private struct page_map

Christoph Hellwig
2017-12-29T07:50:28Z

From: Logan Gunthorpe <logang@deltatee.com>

'struct page_map' is a private structure of 'struct dev_pagemap' but the
latter replicates all the same fields as the former so there isn't much
value in it. Thus drop it in favour of a completely public struct.

This is a clean up in preperation for a more generally useful
'devm_memeremap_pages' interface.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
---
include/linux/memremap.h | 5 ++--
kernel/memremap.c | 68 ++++++++++++++++++------------------------------
mm/hmm.c | 2 +-
3 files changed, 30 insertions(+), 45 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 3fddcfe57bb0..1cb5f39d25c1 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -113,8 +113,9 @@ typedef void (*dev_page_free_t)(struct page *page, void *data);
struct dev_pagemap {
dev_page_fault_t page_fault;
dev_page_free_t page_free;
- struct vmem_altmap *altmap;
- const struct resource *res;
+ struct vmem_altmap altmap;
+ bool altmap_valid;
+ struct resource res;
struct percpu_ref *ref;
struct device *dev;
void *data;
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 12e78528fea4..9207c44cce20 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -188,13 +188,6 @@ static RADIX_TREE(pgmap_radix, GFP_KERNEL);
#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)

-struct page_map {
- struct resource res;
- struct percpu_ref *ref;
- struct dev_pagemap pgmap;
- struct vmem_altmap altmap;
-};
-
static unsigned long order_at(struct resource *res, unsigned long pgoff)
{
unsigned long phys_pgoff = PHYS_PFN(res->start) + pgoff;
@@ -260,22 +253,21 @@ static void pgmap_radix_release(struct resource *res)
synchronize_rcu();
}

-static unsigned long pfn_first(struct page_map *page_map)
+static unsigned long pfn_first(struct dev_pagemap *pgmap)
{
- struct dev_pagemap *pgmap = &page_map->pgmap;
- const struct resource *res = &page_map->res;
- struct vmem_altmap *altmap = pgmap->altmap;
+ const struct resource *res = &pgmap->res;
+ struct vmem_altmap *altmap = &pgmap->altmap;
unsigned long pfn;

pfn = res->start >> PAGE_SHIFT;
- if (altmap)
+ if (pgmap->altmap_valid)
pfn += vmem_altmap_offset(altmap);
return pfn;
}

-static unsigned long pfn_end(struct page_map *page_map)
+static unsigned long pfn_end(struct dev_pagemap *pgmap)
{
- const struct resource *res = &page_map->res;
+ const struct resource *res = &pgmap->res;

return (res->start + resource_size(res)) >> PAGE_SHIFT;
}
@@ -285,13 +277,12 @@ static unsigned long pfn_end(struct page_map *page_map)

static void devm_memremap_pages_release(struct device *dev, void *data)
{
- struct page_map *page_map = data;
- struct resource *res = &page_map->res;
+ struct dev_pagemap *pgmap = data;
+ struct resource *res = &pgmap->res;
resource_size_t align_start, align_size;
- struct dev_pagemap *pgmap = &page_map->pgmap;
unsigned long pfn;

- for_each_device_pfn(pfn, page_map)
+ for_each_device_pfn(pfn, pgmap)
put_page(pfn_to_page(pfn));

if (percpu_ref_tryget_live(pgmap->ref)) {
@@ -304,24 +295,22 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
align_size = ALIGN(resource_size(res), SECTION_SIZE);

mem_hotplug_begin();
- arch_remove_memory(align_start, align_size, pgmap->altmap);
+ arch_remove_memory(align_start, align_size, pgmap->altmap_valid ?
+ &pgmap->altmap : NULL);
mem_hotplug_done();

untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
pgmap_radix_release(res);
- dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
- "%s: failed to free all reserved pages\n", __func__);
+ dev_WARN_ONCE(dev, pgmap->altmap.alloc,
+ "%s: failed to free all reserved pages\n", __func__);
}

/* assumes rcu_read_lock() held at entry */
static struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
{
- struct page_map *page_map;
-
WARN_ON_ONCE(!rcu_read_lock_held());

- page_map = radix_tree_lookup(&pgmap_radix, PHYS_PFN(phys));
- return page_map ? &page_map->pgmap : NULL;
+ return radix_tree_lookup(&pgmap_radix, PHYS_PFN(phys));
}

/**
@@ -349,7 +338,6 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
unsigned long pfn, pgoff, order;
pgprot_t pgprot = PAGE_KERNEL;
struct dev_pagemap *pgmap;
- struct page_map *page_map;
int error, nid, is_ram, i = 0;

align_start = res->start & ~(SECTION_SIZE - 1);
@@ -370,22 +358,20 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
if (!ref)
return ERR_PTR(-EINVAL);

- page_map = devres_alloc_node(devm_memremap_pages_release,
- sizeof(*page_map), GFP_KERNEL, dev_to_node(dev));
- if (!page_map)
+ pgmap = devres_alloc_node(devm_memremap_pages_release,
+ sizeof(*pgmap), GFP_KERNEL, dev_to_node(dev));
+ if (!pgmap)
return ERR_PTR(-ENOMEM);
- pgmap = &page_map->pgmap;

- memcpy(&page_map->res, res, sizeof(*res));
+ memcpy(&pgmap->res, res, sizeof(*res));

pgmap->dev = dev;
if (altmap) {
- memcpy(&page_map->altmap, altmap, sizeof(*altmap));
- pgmap->altmap = &page_map->altmap;
- altmap = pgmap->altmap;
+ memcpy(&pgmap->altmap, altmap, sizeof(*altmap));
+ pgmap->altmap_valid = true;
+ altmap = &pgmap->altmap;
}
pgmap->ref = ref;
- pgmap->res = &page_map->res;
pgmap->type = MEMORY_DEVICE_HOST;
pgmap->page_fault = NULL;
pgmap->page_free = NULL;
@@ -397,7 +383,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,

foreach_order_pgoff(res, order, pgoff) {
error = __radix_tree_insert(&pgmap_radix,
- PHYS_PFN(res->start) + pgoff, order, page_map);
+ PHYS_PFN(res->start) + pgoff, order, pgmap);
if (error) {
dev_err(dev, "%s: failed: %d\n", __func__, error);
break;
@@ -426,7 +412,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
if (error)
goto err_add_memory;

- for_each_device_pfn(pfn, page_map) {
+ for_each_device_pfn(pfn, pgmap) {
struct page *page = pfn_to_page(pfn);

/*
@@ -441,7 +427,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
if (!(++i % 1024))
cond_resched();
}
- devres_add(dev, page_map);
+ devres_add(dev, pgmap);
return __va(res->start);

err_add_memory:
@@ -449,7 +435,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
err_pfn_remap:
err_radix:
pgmap_radix_release(res);
- devres_free(page_map);
+ devres_free(pgmap);
return ERR_PTR(error);
}
EXPORT_SYMBOL(devm_memremap_pages);
@@ -482,9 +468,7 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
* In the cached case we're already holding a live reference.
*/
if (pgmap) {
- const struct resource *res = pgmap ? pgmap->res : NULL;
-
- if (res && phys >= res->start && phys <= res->end)
+ if (phys >= pgmap->res.start && phys <= pgmap->res.end)
return pgmap;
put_dev_pagemap(pgmap);
}
diff --git a/mm/hmm.c b/mm/hmm.c
index 2f2e13c61040..320fdc87f064 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -882,7 +882,7 @@ static int hmm_devmem_pages_create(struct hmm_devmem *devmem)
else
devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;

- devmem->pagemap.res = devmem->resource;
+ devmem->pagemap.res = *devmem->resource;
devmem->pagemap.page_fault = hmm_devmem_fault;
devmem->pagemap.page_free = hmm_devmem_free;
devmem->pagemap.dev = devmem->device;