Commit 3ed2dcdf authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jason Gunthorpe
Browse files

memremap: validate the pagemap type passed to devm_memremap_pages 



Most pgmap types are only supported when certain config options are
enabled.  Check for a type that is valid for the current configuration
before setting up the pagemap.  For this the usage of the 0 type for
device dax gets replaced with an explicit MEMORY_DEVICE_DEVDAX type.

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 0092908d

drivers/dax/device.c

+1 −0
Original line number Diff line number Diff line
@@ -468,6 +468,7 @@ int dev_dax_probe(struct device *dev) 
	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;

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

	if (IS_ERR(addr))

		return PTR_ERR(addr);

include/linux/memremap.h

+8 −0
Original line number Diff line number Diff line
@@ -45,13 +45,21 @@ struct vmem_altmap { 
 * wakeup is used to coordinate physical address space management (ex:

 * fs truncate/hole punch) vs pinned pages (ex: device dma).

 *

 * MEMORY_DEVICE_DEVDAX:

 * Host memory that has similar access semantics as System RAM i.e. DMA

 * coherent and supports page pinning. In contrast to

 * MEMORY_DEVICE_FS_DAX, this memory is access via a device-dax

 * character device.

 *

 * MEMORY_DEVICE_PCI_P2PDMA:

 * Device memory residing in a PCI BAR intended for use with Peer-to-Peer

 * transactions.

 */

enum memory_type {

	/* 0 is reserved to catch uninitialized type fields */

	MEMORY_DEVICE_PRIVATE = 1,

	MEMORY_DEVICE_FS_DAX,

	MEMORY_DEVICE_DEVDAX,

	MEMORY_DEVICE_PCI_P2PDMA,

};

kernel/memremap.c

+22 −0
Original line number Diff line number Diff line
@@ -157,6 +157,28 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) 
	pgprot_t pgprot = PAGE_KERNEL;

	int error, nid, is_ram;



	switch (pgmap->type) {

	case MEMORY_DEVICE_PRIVATE:

		if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {

			WARN(1, "Device private memory not supported\n");

			return ERR_PTR(-EINVAL);

		}

		break;

	case MEMORY_DEVICE_FS_DAX:

		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||

		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {

			WARN(1, "File system DAX not supported\n");

			return ERR_PTR(-EINVAL);

		}

		break;

	case MEMORY_DEVICE_DEVDAX:

	case MEMORY_DEVICE_PCI_P2PDMA:

		break;

	default:

		WARN(1, "Invalid pgmap type %d\n", pgmap->type);

		break;

	}



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

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

		return ERR_PTR(-EINVAL);

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