diff options
| -rw-r--r-- | drivers/nvdimm/pmem.c | 6 | ||||
| -rw-r--r-- | include/linux/list.h | 11 | ||||
| -rw-r--r-- | include/linux/memremap.h | 49 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 5 | ||||
| -rw-r--r-- | kernel/memremap.c | 53 | ||||
| -rw-r--r-- | lib/list_debug.c | 9 |
6 files changed, 125 insertions, 8 deletions
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 328173d7e1ac..7edf31671dab 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -184,7 +184,7 @@ static struct pmem_device *pmem_alloc(struct device *dev, pmem->pfn_flags = PFN_DEV; if (pmem_should_map_pages(dev)) { pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res, - NULL); + &q->q_usage_counter, NULL); pmem->pfn_flags |= PFN_MAP; } else pmem->virt_addr = (void __pmem *) devm_memremap(dev, @@ -365,6 +365,7 @@ static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns) struct vmem_altmap *altmap; struct nd_pfn_sb *pfn_sb; struct pmem_device *pmem; + struct request_queue *q; phys_addr_t offset; int rc; struct vmem_altmap __altmap = { @@ -406,9 +407,10 @@ static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns) /* establish pfn range for lookup, and switch to direct map */ pmem = dev_get_drvdata(dev); + q = pmem->pmem_queue; devm_memunmap(dev, (void __force *) pmem->virt_addr); pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res, - altmap); + &q->q_usage_counter, altmap); pmem->pfn_flags |= PFN_MAP; if (IS_ERR(pmem->virt_addr)) { rc = PTR_ERR(pmem->virt_addr); diff --git a/include/linux/list.h b/include/linux/list.h index 5356f4d661a7..30cf4200ab40 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -113,6 +113,17 @@ extern void __list_del_entry(struct list_head *entry); extern void list_del(struct list_head *entry); #endif +#ifdef CONFIG_DEBUG_LIST +/* + * See devm_memremap_pages() which wants DEBUG_LIST=y to assert if one + * of the pages it allocates is ever passed to list_add() + */ +extern void list_force_poison(struct list_head *entry); +#else +/* fallback to the less strict LIST_POISON* definitions */ +#define list_force_poison list_del +#endif + /** * list_replace - replace old entry by new one * @old : the element to be replaced diff --git a/include/linux/memremap.h b/include/linux/memremap.h index aa3e82a80d7b..bcaa634139a9 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -1,6 +1,8 @@ #ifndef _LINUX_MEMREMAP_H_ #define _LINUX_MEMREMAP_H_ #include <linux/mm.h> +#include <linux/ioport.h> +#include <linux/percpu-refcount.h> struct resource; struct device; @@ -36,21 +38,25 @@ static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start) /** * struct dev_pagemap - metadata for ZONE_DEVICE mappings * @altmap: pre-allocated/reserved memory for vmemmap allocations + * @res: physical address range covered by @ref + * @ref: reference count that pins the devm_memremap_pages() mapping * @dev: host device of the mapping for debug */ struct dev_pagemap { struct vmem_altmap *altmap; const struct resource *res; + struct percpu_ref *ref; struct device *dev; }; #ifdef CONFIG_ZONE_DEVICE void *devm_memremap_pages(struct device *dev, struct resource *res, - struct vmem_altmap *altmap); + struct percpu_ref *ref, struct vmem_altmap *altmap); struct dev_pagemap *find_dev_pagemap(resource_size_t phys); #else static inline void *devm_memremap_pages(struct device *dev, - struct resource *res, struct vmem_altmap *altmap) + struct resource *res, struct percpu_ref *ref, + struct vmem_altmap *altmap) { /* * Fail attempts to call devm_memremap_pages() without @@ -66,4 +72,43 @@ static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys) return NULL; } #endif + +/** + * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn + * @pfn: page frame number to lookup page_map + * @pgmap: optional known pgmap that already has a reference + * + * @pgmap allows the overhead of a lookup to be bypassed when @pfn lands in the + * same mapping. + */ +static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, + struct dev_pagemap *pgmap) +{ + const struct resource *res = pgmap ? pgmap->res : NULL; + resource_size_t phys = PFN_PHYS(pfn); + + /* + * In the cached case we're already holding a live reference so + * we can simply do a blind increment + */ + if (res && phys >= res->start && phys <= res->end) { + percpu_ref_get(pgmap->ref); + return pgmap; + } + + /* fall back to slow path lookup */ + rcu_read_lock(); + pgmap = find_dev_pagemap(phys); + if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) + pgmap = NULL; + rcu_read_unlock(); + + return pgmap; +} + +static inline void put_dev_pagemap(struct dev_pagemap *pgmap) +{ + if (pgmap) + percpu_ref_put(pgmap->ref); +} #endif /* _LINUX_MEMREMAP_H_ */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 2dd9c313a8c0..d3ebb9d21a53 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -116,6 +116,11 @@ struct page { * Can be used as a generic list * by the page owner. */ + struct dev_pagemap *pgmap; /* ZONE_DEVICE pages are never on an + * lru or handled by a slab + * allocator, this points to the + * hosting device page map. + */ struct { /* slub per cpu partial pages */ struct page *next; /* Next partial slab */ #ifdef CONFIG_64BIT diff --git a/kernel/memremap.c b/kernel/memremap.c index 562f6471fe90..3eb8944265d5 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -179,6 +179,29 @@ static void pgmap_radix_release(struct resource *res) mutex_unlock(&pgmap_lock); } +static unsigned long pfn_first(struct page_map *page_map) +{ + struct dev_pagemap *pgmap = &page_map->pgmap; + const struct resource *res = &page_map->res; + struct vmem_altmap *altmap = pgmap->altmap; + unsigned long pfn; + + pfn = res->start >> PAGE_SHIFT; + if (altmap) + pfn += vmem_altmap_offset(altmap); + return pfn; +} + +static unsigned long pfn_end(struct page_map *page_map) +{ + const struct resource *res = &page_map->res; + + return (res->start + resource_size(res)) >> PAGE_SHIFT; +} + +#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) { struct page_map *page_map = data; @@ -186,6 +209,11 @@ static void devm_memremap_pages_release(struct device *dev, void *data) resource_size_t align_start, align_size; struct dev_pagemap *pgmap = &page_map->pgmap; + if (percpu_ref_tryget_live(pgmap->ref)) { + dev_WARN(dev, "%s: page mapping is still live!\n", __func__); + percpu_ref_put(pgmap->ref); + } + pgmap_radix_release(res); /* pages are dead and unused, undo the arch mapping */ @@ -211,20 +239,26 @@ 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 * - * Note, the expectation is that @res is 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. + * Notes: + * 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time + * (or devm release event). + * + * 2/ @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 vmem_altmap *altmap) + struct percpu_ref *ref, struct vmem_altmap *altmap) { int is_ram = region_intersects(res->start, resource_size(res), "System RAM"); resource_size_t key, align_start, align_size; struct dev_pagemap *pgmap; struct page_map *page_map; + unsigned long pfn; int error, nid; if (is_ram == REGION_MIXED) { @@ -242,6 +276,9 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, return ERR_PTR(-ENXIO); } + 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) @@ -255,6 +292,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, memcpy(&page_map->altmap, altmap, sizeof(*altmap)); pgmap->altmap = &page_map->altmap; } + pgmap->ref = ref; pgmap->res = &page_map->res; mutex_lock(&pgmap_lock); @@ -292,6 +330,13 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, if (error) goto err_add_memory; + for_each_device_pfn(pfn, page_map) { + struct page *page = pfn_to_page(pfn); + + /* ZONE_DEVICE pages must never appear on a slab lru */ + list_force_poison(&page->lru); + page->pgmap = pgmap; + } devres_add(dev, page_map); return __va(res->start); diff --git a/lib/list_debug.c b/lib/list_debug.c index 3859bf63561c..3345a089ef7b 100644 --- a/lib/list_debug.c +++ b/lib/list_debug.c @@ -12,6 +12,13 @@ #include <linux/kernel.h> #include <linux/rculist.h> +static struct list_head force_poison; +void list_force_poison(struct list_head *entry) +{ + entry->next = &force_poison; + entry->prev = &force_poison; +} + /* * Insert a new entry between two known consecutive entries. * @@ -23,6 +30,8 @@ void __list_add(struct list_head *new, struct list_head *prev, struct list_head *next) { + WARN(new->next == &force_poison || new->prev == &force_poison, + "list_add attempted on force-poisoned entry\n"); WARN(next->prev != prev, "list_add corruption. next->prev should be " "prev (%p), but was %p. (next=%p).\n", |