Commit f6a55e1a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jason Gunthorpe
Browse files

memremap: lift the devmap_enable manipulation into devm_memremap_pages 



Just check if there is a ->page_free operation set and take care of the
static key enable, as well as the put using device managed resources.
Also check that a ->page_free is provided for the pgmaps types that
require it, and check for a valid type as well while we are at it.

Note that this also fixes the fact that hmm never called
dev_pagemap_put_ops and thus would leave the slow path enabled forever,
even after a device driver unload or disable.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Tested-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent d8668bb0

drivers/nvdimm/pmem.c

+4 −19
Original line number Diff line number Diff line
@@ -334,11 +334,6 @@ static void pmem_release_disk(void *__pmem) 
	put_disk(pmem->disk);

}



static void pmem_release_pgmap_ops(void *__pgmap)

{

	dev_pagemap_put_ops();

}



static void pmem_pagemap_page_free(struct page *page, void *data)

{

	wake_up_var(&page->_refcount);
@@ -350,16 +345,6 @@ static const struct dev_pagemap_ops fsdax_pagemap_ops = { 
	.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->ops = &fsdax_pagemap_ops;

	return 0;

}



static int pmem_attach_disk(struct device *dev,

		struct nd_namespace_common *ndns)

{
@@ -415,8 +400,8 @@ static int pmem_attach_disk(struct device *dev, 
	pmem->pfn_flags = PFN_DEV;

	pmem->pgmap.ref = &q->q_usage_counter;

	if (is_nd_pfn(dev)) {

		if (setup_pagemap_fsdax(dev, &pmem->pgmap))

			return -ENOMEM;

		pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;

		pmem->pgmap.ops = &fsdax_pagemap_ops;

		addr = devm_memremap_pages(dev, &pmem->pgmap);

		pfn_sb = nd_pfn->pfn_sb;

		pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
@@ -428,8 +413,8 @@ static int pmem_attach_disk(struct device *dev, 
	} else if (pmem_should_map_pages(dev)) {

		memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));

		pmem->pgmap.altmap_valid = false;

		if (setup_pagemap_fsdax(dev, &pmem->pgmap))

			return -ENOMEM;

		pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;

		pmem->pgmap.ops = &fsdax_pagemap_ops;

		addr = devm_memremap_pages(dev, &pmem->pgmap);

		pmem->pfn_flags |= PFN_MAP;

		memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));

include/linux/mm.h

+0 −10
Original line number Diff line number Diff line
@@ -932,8 +932,6 @@ static inline bool is_zone_device_page(const struct page *page) 
#endif



#ifdef CONFIG_DEV_PAGEMAP_OPS

void dev_pagemap_get_ops(void);

void dev_pagemap_put_ops(void);

void __put_devmap_managed_page(struct page *page);

DECLARE_STATIC_KEY_FALSE(devmap_managed_key);

static inline bool put_devmap_managed_page(struct page *page)
@@ -973,14 +971,6 @@ static inline bool is_pci_p2pdma_page(const struct page *page) 
#endif /* CONFIG_PCI_P2PDMA */



#else /* CONFIG_DEV_PAGEMAP_OPS */

static inline void dev_pagemap_get_ops(void)

{

}



static inline void dev_pagemap_put_ops(void)

{

}



static inline bool put_devmap_managed_page(struct page *page)

{

	return false;

kernel/memremap.c

+37 −22
Original line number Diff line number Diff line
@@ -17,6 +17,35 @@ static DEFINE_XARRAY(pgmap_array); 
#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)

#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)



#ifdef CONFIG_DEV_PAGEMAP_OPS

DEFINE_STATIC_KEY_FALSE(devmap_managed_key);

EXPORT_SYMBOL(devmap_managed_key);

static atomic_t devmap_managed_enable;



static void devmap_managed_enable_put(void *data)

{

	if (atomic_dec_and_test(&devmap_managed_enable))

		static_branch_disable(&devmap_managed_key);

}



static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)

{

	if (!pgmap->ops->page_free) {

		WARN(1, "Missing page_free method\n");

		return -EINVAL;

	}



	if (atomic_inc_return(&devmap_managed_enable) == 1)

		static_branch_enable(&devmap_managed_key);

	return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);

}

#else

static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)

{

	return -EINVAL;

}

#endif /* CONFIG_DEV_PAGEMAP_OPS */



#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)

vm_fault_t device_private_entry_fault(struct vm_area_struct *vma,

		       unsigned long addr,
@@ -156,6 +185,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) 
	};

	pgprot_t pgprot = PAGE_KERNEL;

	int error, nid, is_ram;

	bool need_devmap_managed = true;



	switch (pgmap->type) {

	case MEMORY_DEVICE_PRIVATE:
@@ -173,6 +203,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) 
		break;

	case MEMORY_DEVICE_DEVDAX:

	case MEMORY_DEVICE_PCI_P2PDMA:

		need_devmap_managed = false;

		break;

	default:

		WARN(1, "Invalid pgmap type %d\n", pgmap->type);
@@ -185,6 +216,12 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) 
		return ERR_PTR(-EINVAL);

	}



	if (need_devmap_managed) {

		error = devmap_managed_enable_get(dev, pgmap);

		if (error)

			return ERR_PTR(error);

	}



	align_start = res->start & ~(SECTION_SIZE - 1);

	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)

		- align_start;
@@ -351,28 +388,6 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, 
EXPORT_SYMBOL_GPL(get_dev_pagemap);



#ifdef CONFIG_DEV_PAGEMAP_OPS

DEFINE_STATIC_KEY_FALSE(devmap_managed_key);

EXPORT_SYMBOL(devmap_managed_key);

static atomic_t devmap_enable;



/*

 * Toggle the static key for ->page_free() callbacks when dev_pagemap

 * pages go idle.

 */

void dev_pagemap_get_ops(void)

{

	if (atomic_inc_return(&devmap_enable) == 1)

		static_branch_enable(&devmap_managed_key);

}

EXPORT_SYMBOL_GPL(dev_pagemap_get_ops);



void dev_pagemap_put_ops(void)

{

	if (atomic_dec_and_test(&devmap_enable))

		static_branch_disable(&devmap_managed_key);

}

EXPORT_SYMBOL_GPL(dev_pagemap_put_ops);



void __put_devmap_managed_page(struct page *page)

{

	int count = page_ref_dec_return(page);

mm/hmm.c

+0 −2
Original line number Diff line number Diff line
@@ -1415,8 +1415,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, 
	void *result;

	int ret;



	dev_pagemap_get_ops();



	devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL);

	if (!devmem)

		return ERR_PTR(-ENOMEM);

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