Commit a455aa72 authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds
Browse files

device-dax/kmem: fix resource release 



The conversion to request_mem_region() is broken because it assumes that
the range is marked busy prior to release.  However, due to the way that
the kmem driver manipulates the IORESOURCE_BUSY flag (clears it to let
{add,remove}_memory() handle busy) it requires a manual release_resource()
to perform cleanup.

Given that the actual 'struct resource *' needs to be recalled, not just
the range, add that tracking to the kmem driver-data.

Fixes: 0513bd5b ("device-dax/kmem: replace release_resource() with release_mem_region()")
Reported-by: default avatarDavid Hildenbrand <david@redhat.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jia He <justin.he@arm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lkml.kernel.org/r/160272252925.3136502.17220638073995895400.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 578a7155

drivers/dax/kmem.c

+34 −14
Original line number Diff line number Diff line
@@ -35,11 +35,17 @@ static int dax_kmem_range(struct dev_dax *dev_dax, int i, struct range *r) 
	return 0;

}



struct dax_kmem_data {

	const char *res_name;

	struct resource *res[];

};



static int dev_dax_kmem_probe(struct dev_dax *dev_dax)

{

	struct device *dev = &dev_dax->dev;

	struct dax_kmem_data *data;

	int rc = -ENOMEM;

	int i, mapped = 0;

	char *res_name;

	int numa_node;



	/*
@@ -55,14 +61,17 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) 
		return -EINVAL;

	}



	res_name = kstrdup(dev_name(dev), GFP_KERNEL);

	if (!res_name)

	data = kzalloc(sizeof(*data) + sizeof(struct resource *) * dev_dax->nr_range, GFP_KERNEL);

	if (!data)

		return -ENOMEM;



	data->res_name = kstrdup(dev_name(dev), GFP_KERNEL);

	if (!data->res_name)

		goto err_res_name;



	for (i = 0; i < dev_dax->nr_range; i++) {

		struct resource *res;

		struct range range;

		int rc;



		rc = dax_kmem_range(dev_dax, i, &range);

		if (rc) {
@@ -72,7 +81,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) 
		}



		/* Region is permanently reserved if hotremove fails. */

		res = request_mem_region(range.start, range_len(&range), res_name);

		res = request_mem_region(range.start, range_len(&range), data->res_name);

		if (!res) {

			dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve region\n",

					i, range.start, range.end);
@@ -82,9 +91,10 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) 
			 */

			if (mapped)

				continue;

			kfree(res_name);

			return -EBUSY;

			rc = -EBUSY;

			goto err_request_mem;

		}

		data->res[i] = res;



		/*

		 * Set flags appropriate for System RAM.  Leave ..._BUSY clear
@@ -104,18 +114,25 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) 
		if (rc) {

			dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n",

					i, range.start, range.end);

			release_mem_region(range.start, range_len(&range));

			release_resource(res);

			kfree(res);

			data->res[i] = NULL;

			if (mapped)

				continue;

			kfree(res_name);

			return rc;

			goto err_request_mem;

		}

		mapped++;

	}



	dev_set_drvdata(dev, res_name);

	dev_set_drvdata(dev, data);



	return 0;



err_request_mem:

	kfree(data->res_name);

err_res_name:

	kfree(data);

	return rc;

}



#ifdef CONFIG_MEMORY_HOTREMOVE
@@ -123,7 +140,7 @@ static int dev_dax_kmem_remove(struct dev_dax *dev_dax) 
{

	int i, success = 0;

	struct device *dev = &dev_dax->dev;

	const char *res_name = dev_get_drvdata(dev);

	struct dax_kmem_data *data = dev_get_drvdata(dev);



	/*

	 * We have one shot for removing memory, if some memory blocks were not
@@ -142,7 +159,9 @@ static int dev_dax_kmem_remove(struct dev_dax *dev_dax) 
		rc = remove_memory(dev_dax->target_node, range.start,

				range_len(&range));

		if (rc == 0) {

			release_mem_region(range.start, range_len(&range));

			release_resource(data->res[i]);

			kfree(data->res[i]);

			data->res[i] = NULL;

			success++;

			continue;

		}
@@ -153,7 +172,8 @@ static int dev_dax_kmem_remove(struct dev_dax *dev_dax) 
	}



	if (success >= dev_dax->nr_range) {

		kfree(res_name);

		kfree(data->res_name);

		kfree(data);

		dev_set_drvdata(dev, NULL);

	}