path: root/mm/sparse-vmemmap.c
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authorDan Williams <>2016-01-15 16:56:19 -0800
committerLinus Torvalds <>2016-01-15 17:56:32 -0800
commit9476df7d80dfc425b37bfecf1d89edf8ec81fcb6 (patch)
treec18eecb4a2f369c45e2c45053e02853640c9005c /mm/sparse-vmemmap.c
parent260ae3f7db614a5c4aa4b773599f99adc1d9859e (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 <> Tested-by: Logan Gunthorpe <> Cc: Christoph Hellwig <> Cc: Dave Chinner <> Cc: Ross Zwisler <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'mm/sparse-vmemmap.c')
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