memremap: move dev_pagemap callbacks into a separate structure

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

View File

@ -36,9 +36,8 @@ static void dev_dax_percpu_exit(struct percpu_ref *ref)
percpu_ref_exit(ref);
}
static void dev_dax_percpu_kill(struct percpu_ref *data)
static void dev_dax_percpu_kill(struct percpu_ref *ref)
{
struct percpu_ref *ref = data;
struct dev_dax *dev_dax = ref_to_dev_dax(ref);
dev_dbg(&dev_dax->dev, "%s\n", __func__);
@ -442,6 +441,11 @@ static void dev_dax_kill(void *dev_dax)
kill_dev_dax(dev_dax);
}
static const struct dev_pagemap_ops dev_dax_pagemap_ops = {
.kill = dev_dax_percpu_kill,
.cleanup = dev_dax_percpu_exit,
};
int dev_dax_probe(struct device *dev)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
@ -466,9 +470,8 @@ int dev_dax_probe(struct device *dev)
return rc;
dev_dax->pgmap.ref = &dev_dax->ref;
dev_dax->pgmap.kill = dev_dax_percpu_kill;
dev_dax->pgmap.cleanup = dev_dax_percpu_exit;
dev_dax->pgmap.type = MEMORY_DEVICE_DEVDAX;
dev_dax->pgmap.ops = &dev_dax_pagemap_ops;
addr = devm_memremap_pages(dev, &dev_dax->pgmap);
if (IS_ERR(addr))
return PTR_ERR(addr);

View File

@ -16,7 +16,7 @@ struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys)
struct dev_dax *dev_dax;
struct nd_namespace_io *nsio;
struct dax_region *dax_region;
struct dev_pagemap pgmap = { 0 };
struct dev_pagemap pgmap = { };
struct nd_namespace_common *ndns;
struct nd_dax *nd_dax = to_nd_dax(dev);
struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;

View File

@ -303,7 +303,7 @@ static const struct attribute_group *pmem_attribute_groups[] = {
NULL,
};
static void __pmem_release_queue(struct percpu_ref *ref)
static void pmem_pagemap_cleanup(struct percpu_ref *ref)
{
struct request_queue *q;
@ -313,10 +313,10 @@ static void __pmem_release_queue(struct percpu_ref *ref)
static void pmem_release_queue(void *ref)
{
__pmem_release_queue(ref);
pmem_pagemap_cleanup(ref);
}
static void pmem_freeze_queue(struct percpu_ref *ref)
static void pmem_pagemap_kill(struct percpu_ref *ref)
{
struct request_queue *q;
@ -339,19 +339,24 @@ static void pmem_release_pgmap_ops(void *__pgmap)
dev_pagemap_put_ops();
}
static void fsdax_pagefree(struct page *page, void *data)
static void pmem_pagemap_page_free(struct page *page, void *data)
{
wake_up_var(&page->_refcount);
}
static const struct dev_pagemap_ops fsdax_pagemap_ops = {
.page_free = pmem_pagemap_page_free,
.kill = pmem_pagemap_kill,
.cleanup = pmem_pagemap_cleanup,
};
static int setup_pagemap_fsdax(struct device *dev, struct dev_pagemap *pgmap)
{
dev_pagemap_get_ops();
if (devm_add_action_or_reset(dev, pmem_release_pgmap_ops, pgmap))
return -ENOMEM;
pgmap->type = MEMORY_DEVICE_FS_DAX;
pgmap->page_free = fsdax_pagefree;
pgmap->ops = &fsdax_pagemap_ops;
return 0;
}
@ -409,8 +414,6 @@ static int pmem_attach_disk(struct device *dev,
pmem->pfn_flags = PFN_DEV;
pmem->pgmap.ref = &q->q_usage_counter;
pmem->pgmap.kill = pmem_freeze_queue;
pmem->pgmap.cleanup = __pmem_release_queue;
if (is_nd_pfn(dev)) {
if (setup_pagemap_fsdax(dev, &pmem->pgmap))
return -ENOMEM;

View File

@ -153,6 +153,11 @@ static int pci_p2pdma_setup(struct pci_dev *pdev)
return error;
}
static const struct dev_pagemap_ops pci_p2pdma_pagemap_ops = {
.kill = pci_p2pdma_percpu_kill,
.cleanup = pci_p2pdma_percpu_cleanup,
};
/**
* pci_p2pdma_add_resource - add memory for use as p2p memory
* @pdev: the device to add the memory to
@ -208,8 +213,7 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
pgmap->type = MEMORY_DEVICE_PCI_P2PDMA;
pgmap->pci_p2pdma_bus_offset = pci_bus_address(pdev, bar) -
pci_resource_start(pdev, bar);
pgmap->kill = pci_p2pdma_percpu_kill;
pgmap->cleanup = pci_p2pdma_percpu_cleanup;
pgmap->ops = &pci_p2pdma_pagemap_ops;
addr = devm_memremap_pages(&pdev->dev, pgmap);
if (IS_ERR(addr)) {

View File

@ -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

View File

@ -92,10 +92,10 @@ static void devm_memremap_pages_release(void *data)
unsigned long pfn;
int nid;
pgmap->kill(pgmap->ref);
pgmap->ops->kill(pgmap->ref);
for_each_device_pfn(pfn, pgmap)
put_page(pfn_to_page(pfn));
pgmap->cleanup(pgmap->ref);
pgmap->ops->cleanup(pgmap->ref);
/* pages are dead and unused, undo the arch mapping */
align_start = res->start & ~(SECTION_SIZE - 1);
@ -128,8 +128,8 @@ static void devm_memremap_pages_release(void *data)
* @pgmap: pointer to a struct dev_pagemap
*
* Notes:
* 1/ At a minimum the res, ref and type members of @pgmap must be initialized
* by the caller before passing it to this function
* 1/ At a minimum the res, ref and type and ops members of @pgmap must be
* initialized by the caller before passing it to this function
*
* 2/ The altmap field may optionally be initialized, in which case altmap_valid
* must be set to true
@ -179,7 +179,8 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
break;
}
if (!pgmap->ref || !pgmap->kill || !pgmap->cleanup) {
if (!pgmap->ref || !pgmap->ops || !pgmap->ops->kill ||
!pgmap->ops->cleanup) {
WARN(1, "Missing reference count teardown definition\n");
return ERR_PTR(-EINVAL);
}
@ -293,9 +294,8 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
err_pfn_remap:
pgmap_array_delete(res);
err_array:
pgmap->kill(pgmap->ref);
pgmap->cleanup(pgmap->ref);
pgmap->ops->kill(pgmap->ref);
pgmap->ops->cleanup(pgmap->ref);
return ERR_PTR(error);
}
EXPORT_SYMBOL_GPL(devm_memremap_pages);
@ -388,7 +388,7 @@ void __put_devmap_managed_page(struct page *page)
mem_cgroup_uncharge(page);
page->pgmap->page_free(page, page->pgmap->data);
page->pgmap->ops->page_free(page, page->pgmap->data);
} else if (!count)
__put_page(page);
}

View File

@ -1384,6 +1384,12 @@ static void hmm_devmem_free(struct page *page, void *data)
devmem->ops->free(devmem, page);
}
static const struct dev_pagemap_ops hmm_pagemap_ops = {
.page_free = hmm_devmem_free,
.kill = hmm_devmem_ref_kill,
.cleanup = hmm_devmem_ref_exit,
};
/*
* hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory
*
@ -1438,12 +1444,10 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
devmem->pagemap.res = *devmem->resource;
devmem->pagemap.page_free = hmm_devmem_free;
devmem->pagemap.ops = &hmm_pagemap_ops;
devmem->pagemap.altmap_valid = false;
devmem->pagemap.ref = &devmem->ref;
devmem->pagemap.data = devmem;
devmem->pagemap.kill = hmm_devmem_ref_kill;
devmem->pagemap.cleanup = hmm_devmem_ref_exit;
result = devm_memremap_pages(devmem->device, &devmem->pagemap);
if (IS_ERR(result))

View File

@ -100,9 +100,10 @@ static void nfit_test_kill(void *_pgmap)
{
struct dev_pagemap *pgmap = _pgmap;
WARN_ON(!pgmap || !pgmap->ref || !pgmap->kill || !pgmap->cleanup);
pgmap->kill(pgmap->ref);
pgmap->cleanup(pgmap->ref);
WARN_ON(!pgmap || !pgmap->ref || !pgmap->ops || !pgmap->ops->kill ||
!pgmap->ops->cleanup);
pgmap->ops->kill(pgmap->ref);
pgmap->ops->cleanup(pgmap->ref);
}
void *__wrap_devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)