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memremap: move dev_pagemap callbacks into a separate structure

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The dev_pagemap is a growing too many callbacks.  Move them into a
separate ops structure so that they are not duplicated for multiple
instances, and an attacker can't easily overwrite them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Christoph Hellwig
2019-06-26 14:27:08 +02:00
committed by Jason Gunthorpe
parent 3ed2dcdf54
commit 1e240e8d4a
8 changed files with 65 additions and 46 deletions
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36
include/linux/memremap.h
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@@ -63,41 +63,45 @@ enum memory_type {
MEMORY_DEVICE_PCI_P2PDMA,
};
/*
* Additional notes about MEMORY_DEVICE_PRIVATE may be found in
* include/linux/hmm.h and Documentation/vm/hmm.rst. There is also a brief
* explanation in include/linux/memory_hotplug.h.
*
* The page_free() callback is called once the page refcount reaches 1
* (ZONE_DEVICE pages never reach 0 refcount unless there is a refcount bug.
* This allows the device driver to implement its own memory management.)
*/
typedef void (*dev_page_free_t)(struct page *page, void *data);
struct dev_pagemap_ops {
/*
* Called once the page refcount reaches 1. (ZONE_DEVICE pages never
* reach 0 refcount unless there is a refcount bug. This allows the
* device driver to implement its own memory management.)
*/
void (*page_free)(struct page *page, void *data);
/*
* Transition the refcount in struct dev_pagemap to the dead state.
*/
void (*kill)(struct percpu_ref *ref);
/*
* Wait for refcount in struct dev_pagemap to be idle and reap it.
*/
void (*cleanup)(struct percpu_ref *ref);
};
/**
* struct dev_pagemap - metadata for ZONE_DEVICE mappings
* @page_free: free page callback when page refcount reaches 1
* @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
* @kill: callback to transition @ref to the dead state
* @cleanup: callback to wait for @ref to be idle and reap it
* @dev: host device of the mapping for debug
* @data: private data pointer for page_free()
* @type: memory type: see MEMORY_* in memory_hotplug.h
* @ops: method table
*/
struct dev_pagemap {
dev_page_free_t page_free;
struct vmem_altmap altmap;
bool altmap_valid;
struct resource res;
struct percpu_ref *ref;
void (*kill)(struct percpu_ref *ref);
void (*cleanup)(struct percpu_ref *ref);
struct device *dev;
void *data;
enum memory_type type;
u64 pci_p2pdma_bus_offset;
const struct dev_pagemap_ops *ops;
};
#ifdef CONFIG_ZONE_DEVICE