Commit 24917f6b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jason Gunthorpe
Browse files

memremap: provide an optional internal refcount in struct dev_pagemap 



Provide an internal refcounting logic if no ->ref field is provided
in the pagemap passed into devm_memremap_pages so that callers don't
have to reinvent it poorly.

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 514caf23

include/linux/memremap.h

+4 −0
Original line number Diff line number Diff line
@@ -95,6 +95,8 @@ struct dev_pagemap_ops { 
 * @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

 * @internal_ref: internal reference if @ref is not provided by the caller

 * @done: completion for @internal_ref

 * @dev: host device of the mapping for debug

 * @data: private data pointer for page_free()

 * @type: memory type: see MEMORY_* in memory_hotplug.h
@@ -105,6 +107,8 @@ struct dev_pagemap { 
	struct vmem_altmap altmap;

	struct resource res;

	struct percpu_ref *ref;

	struct percpu_ref internal_ref;

	struct completion done;

	struct device *dev;

	enum memory_type type;

	unsigned int flags;

kernel/memremap.c

+51 −13
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ static void devmap_managed_enable_put(void *data) 


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

{

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

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

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

		return -EINVAL;

	}
@@ -75,6 +75,24 @@ static unsigned long pfn_next(unsigned long pfn) 
#define for_each_device_pfn(pfn, map) \

	for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))



static void dev_pagemap_kill(struct dev_pagemap *pgmap)

{

	if (pgmap->ops && pgmap->ops->kill)

		pgmap->ops->kill(pgmap);

	else

		percpu_ref_kill(pgmap->ref);

}



static void dev_pagemap_cleanup(struct dev_pagemap *pgmap)

{

	if (pgmap->ops && pgmap->ops->cleanup) {

		pgmap->ops->cleanup(pgmap);

	} else {

		wait_for_completion(&pgmap->done);

		percpu_ref_exit(pgmap->ref);

	}

}



static void devm_memremap_pages_release(void *data)

{

	struct dev_pagemap *pgmap = data;
@@ -84,10 +102,10 @@ static void devm_memremap_pages_release(void *data) 
	unsigned long pfn;

	int nid;



	pgmap->ops->kill(pgmap);

	dev_pagemap_kill(pgmap);

	for_each_device_pfn(pfn, pgmap)

		put_page(pfn_to_page(pfn));

	pgmap->ops->cleanup(pgmap);

	dev_pagemap_cleanup(pgmap);



	/* pages are dead and unused, undo the arch mapping */

	align_start = res->start & ~(SECTION_SIZE - 1);
@@ -114,20 +132,29 @@ static void devm_memremap_pages_release(void *data) 
		      "%s: failed to free all reserved pages\n", __func__);

}



static void dev_pagemap_percpu_release(struct percpu_ref *ref)

{

	struct dev_pagemap *pgmap =

		container_of(ref, struct dev_pagemap, internal_ref);



	complete(&pgmap->done);

}



/**

 * devm_memremap_pages - remap and provide memmap backing for the given resource

 * @dev: hosting device for @res

 * @pgmap: pointer to a struct dev_pagemap

 *

 * Notes:

 * 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

 * 1/ At a minimum the res and type 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

 *    PGMAP_ALTMAP_VALID must be set in pgmap->flags.

 *

 * 3/ pgmap->ref must be 'live' on entry and will be killed and reaped

 *    at devm_memremap_pages_release() time, or if this routine fails.

 * 3/ The ref field may optionally be provided, in which pgmap->ref must be

 *    'live' on entry and will be killed and reaped at

 *    devm_memremap_pages_release() time, or if this routine fails.

 *

 * 4/ res is expected to be a host memory range that could feasibly be

 *    treated as a "System RAM" range, i.e. not a device mmio range, but
@@ -175,11 +202,22 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) 
		break;

	}



	if (!pgmap->ref || !pgmap->ops || !pgmap->ops->kill ||

	    !pgmap->ops->cleanup) {

	if (!pgmap->ref) {

		if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup))

			return ERR_PTR(-EINVAL);



		init_completion(&pgmap->done);

		error = percpu_ref_init(&pgmap->internal_ref,

				dev_pagemap_percpu_release, 0, GFP_KERNEL);

		if (error)

			return ERR_PTR(error);

		pgmap->ref = &pgmap->internal_ref;

	} else {

		if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) {

			WARN(1, "Missing reference count teardown definition\n");

			return ERR_PTR(-EINVAL);

		}

	}



	if (need_devmap_managed) {

		error = devmap_managed_enable_get(dev, pgmap);
@@ -296,8 +334,8 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) 
 err_pfn_remap:

	pgmap_array_delete(res);

 err_array:

	pgmap->ops->kill(pgmap);

	pgmap->ops->cleanup(pgmap);

	dev_pagemap_kill(pgmap);

	dev_pagemap_cleanup(pgmap);

	return ERR_PTR(error);

}

EXPORT_SYMBOL_GPL(devm_memremap_pages);

tools/testing/nvdimm/test/iomap.c

+46 −12
Original line number Diff line number Diff line
@@ -100,26 +100,60 @@ static void nfit_test_kill(void *_pgmap) 
{

	struct dev_pagemap *pgmap = _pgmap;



	WARN_ON(!pgmap || !pgmap->ref || !pgmap->ops || !pgmap->ops->kill ||

		!pgmap->ops->cleanup);

	WARN_ON(!pgmap || !pgmap->ref);



	if (pgmap->ops && pgmap->ops->kill)

		pgmap->ops->kill(pgmap);

	else

		percpu_ref_kill(pgmap->ref);



	if (pgmap->ops && pgmap->ops->cleanup) {

		pgmap->ops->cleanup(pgmap);

	} else {

		wait_for_completion(&pgmap->done);

		percpu_ref_exit(pgmap->ref);

	}

}



static void dev_pagemap_percpu_release(struct percpu_ref *ref)

{

	struct dev_pagemap *pgmap =

		container_of(ref, struct dev_pagemap, internal_ref);



	complete(&pgmap->done);

}



void *__wrap_devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)

{

	int error;

	resource_size_t offset = pgmap->res.start;

	struct nfit_test_resource *nfit_res = get_nfit_res(offset);



	if (nfit_res) {

		int rc;

	if (!nfit_res)

		return devm_memremap_pages(dev, pgmap);



		rc = devm_add_action_or_reset(dev, nfit_test_kill, pgmap);

		if (rc)

			return ERR_PTR(rc);

		return nfit_res->buf + offset - nfit_res->res.start;

	pgmap->dev = dev;

	if (!pgmap->ref) {

		if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup))

			return ERR_PTR(-EINVAL);



		init_completion(&pgmap->done);

		error = percpu_ref_init(&pgmap->internal_ref,

				dev_pagemap_percpu_release, 0, GFP_KERNEL);

		if (error)

			return ERR_PTR(error);

		pgmap->ref = &pgmap->internal_ref;

	} else {

		if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) {

			WARN(1, "Missing reference count teardown definition\n");

			return ERR_PTR(-EINVAL);

		}

	return devm_memremap_pages(dev, pgmap);

	}



	error = devm_add_action_or_reset(dev, nfit_test_kill, pgmap);

	if (error)

		return ERR_PTR(error);

	return nfit_res->buf + offset - nfit_res->res.start;

}

EXPORT_SYMBOL_GPL(__wrap_devm_memremap_pages);

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