diff options
| author | Dan Williams | 2016-01-15 16:56:19 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2016-01-15 17:56:32 -0800 |
| commit | 9476df7d80dfc425b37bfecf1d89edf8ec81fcb6 (patch) | |
| tree | c18eecb4a2f369c45e2c45053e02853640c9005c /include | |
| parent | 260ae3f7db614a5c4aa4b773599f99adc1d9859e (diff) | |
mm: introduce find_dev_pagemap()
There are several scenarios where we need to retrieve and update
metadata associated with a given devm_memremap_pages() mapping, and the
only lookup key available is a pfn in the range:
1/ We want to augment vmemmap_populate() (called via arch_add_memory())
to allocate memmap storage from pre-allocated pages reserved by the
device driver. At vmemmap_alloc_block_buf() time it grabs device pages
rather than page allocator pages. This is in support of
devm_memremap_pages() mappings where the memmap is too large to fit in
main memory (i.e. large persistent memory devices).
2/ Taking a reference against the mapping when inserting device pages
into the address_space radix of a given inode. This facilitates
unmap_mapping_range() and truncate_inode_pages() operations when the
driver is tearing down the mapping.
3/ get_user_pages() operations on ZONE_DEVICE memory require taking a
reference against the mapping so that the driver teardown path can
revoke and drain usage of device pages.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/io.h | 15 | ||||
| -rw-r--r-- | include/linux/memremap.h | 38 |
2 files changed, 38 insertions, 15 deletions
diff --git a/include/linux/io.h b/include/linux/io.h index de64c1e53612..fffd88d7f426 100644 --- a/include/linux/io.h +++ b/include/linux/io.h @@ -89,21 +89,6 @@ void devm_memunmap(struct device *dev, void *addr); void *__devm_memremap_pages(struct device *dev, struct resource *res); -#ifdef CONFIG_ZONE_DEVICE -void *devm_memremap_pages(struct device *dev, struct resource *res); -#else -static inline void *devm_memremap_pages(struct device *dev, struct resource *res) -{ - /* - * Fail attempts to call devm_memremap_pages() without - * ZONE_DEVICE support enabled, this requires callers to fall - * back to plain devm_memremap() based on config - */ - WARN_ON_ONCE(1); - return ERR_PTR(-ENXIO); -} -#endif - /* * Some systems do not have legacy ISA devices. * /dev/port is not a valid interface on these systems. diff --git a/include/linux/memremap.h b/include/linux/memremap.h new file mode 100644 index 000000000000..d90721c178bb --- /dev/null +++ b/include/linux/memremap.h @@ -0,0 +1,38 @@ +#ifndef _LINUX_MEMREMAP_H_ +#define _LINUX_MEMREMAP_H_ +#include <linux/mm.h> + +struct resource; +struct device; +/** + * struct dev_pagemap - metadata for ZONE_DEVICE mappings + * @dev: host device of the mapping for debug + */ +struct dev_pagemap { + /* TODO: vmem_altmap and percpu_ref count */ + struct device *dev; +}; + +#ifdef CONFIG_ZONE_DEVICE +void *devm_memremap_pages(struct device *dev, struct resource *res); +struct dev_pagemap *find_dev_pagemap(resource_size_t phys); +#else +static inline void *devm_memremap_pages(struct device *dev, + struct resource *res) +{ + /* + * Fail attempts to call devm_memremap_pages() without + * ZONE_DEVICE support enabled, this requires callers to fall + * back to plain devm_memremap() based on config + */ + WARN_ON_ONCE(1); + return ERR_PTR(-ENXIO); +} + +static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys) +{ + return NULL; +} +#endif + +#endif /* _LINUX_MEMREMAP_H_ */ |