Some device driver manage multiple physical devices memory from a single fake device driver. In that case the fake device might outlive the real device and ZONE_DEVICE and its resource allocated for a real device would waste resources in the meantime.
This patch allow early removal of ZONE_DEVICE and associated resource, before device driver is tear down. Signed-off-by: Jérôme Glisse <[email protected]> Cc: Dan Williams <[email protected]> Cc: Ross Zwisler <[email protected]> --- include/linux/memremap.h | 7 +++++++ kernel/memremap.c | 14 ++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/include/linux/memremap.h b/include/linux/memremap.h index f7e0609..32314d2 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -53,6 +53,7 @@ struct dev_pagemap { void *devm_memremap_pages(struct device *dev, struct resource *res, struct percpu_ref *ref, struct vmem_altmap *altmap); struct dev_pagemap *find_dev_pagemap(resource_size_t phys); +int devm_memremap_pages_remove(struct device *dev, struct dev_pagemap *pgmap); static inline bool dev_page_allow_migrate(const struct page *page) { @@ -78,6 +79,12 @@ static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys) return NULL; } +static inline int devm_memremap_pages_remove(struct device *dev, + struct dev_pagemap *pgmap) +{ + return -EINVAL; +} + static inline bool dev_page_allow_migrate(const struct page *page) { return false; diff --git a/kernel/memremap.c b/kernel/memremap.c index 07665eb..250ef25 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -387,6 +387,20 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, } EXPORT_SYMBOL(devm_memremap_pages); +static int devm_page_map_match(struct device *dev, void *data, void *match_data) +{ + struct page_map *page_map = data; + + return &page_map->pgmap == match_data; +} + +int devm_memremap_pages_remove(struct device *dev, struct dev_pagemap *pgmap) +{ + return devres_release(dev, &devm_memremap_pages_release, + &devm_page_map_match, pgmap); +} +EXPORT_SYMBOL(devm_memremap_pages_remove); + unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) { /* number of pfns from base where pfn_to_page() is valid */ -- 2.4.3
