9476df7d80
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>
39 lines
915 B
C
39 lines
915 B
C
#ifndef _LINUX_MEMREMAP_H_
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#define _LINUX_MEMREMAP_H_
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#include <linux/mm.h>
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struct resource;
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struct device;
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/**
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* struct dev_pagemap - metadata for ZONE_DEVICE mappings
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* @dev: host device of the mapping for debug
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*/
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struct dev_pagemap {
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/* TODO: vmem_altmap and percpu_ref count */
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struct device *dev;
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};
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#ifdef CONFIG_ZONE_DEVICE
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void *devm_memremap_pages(struct device *dev, struct resource *res);
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struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
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#else
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static inline void *devm_memremap_pages(struct device *dev,
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struct resource *res)
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{
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/*
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* Fail attempts to call devm_memremap_pages() without
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* ZONE_DEVICE support enabled, this requires callers to fall
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* back to plain devm_memremap() based on config
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*/
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WARN_ON_ONCE(1);
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return ERR_PTR(-ENXIO);
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}
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static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
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{
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return NULL;
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}
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#endif
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#endif /* _LINUX_MEMREMAP_H_ */
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