Commit 586f6168 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dan Williams
Browse files

dax: remove the pgmap sanity checks in generic_fsdax_supported 



Drivers that register a dax_dev should make sure it works, no need
to double check from the file system.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-6-hch@lst.de


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent fb08a190

drivers/dax/super.c

+1 −48
Original line number Diff line number Diff line
@@ -106,13 +106,9 @@ bool generic_fsdax_supported(struct dax_device *dax_dev, 
		struct block_device *bdev, int blocksize, sector_t start,

		sector_t sectors)

{

	bool dax_enabled = false;

	pgoff_t pgoff, pgoff_end;

	void *kaddr, *end_kaddr;

	pfn_t pfn, end_pfn;

	sector_t last_page;

	long len, len2;

	int err, id;

	int err;



	if (blocksize != PAGE_SIZE) {

		pr_info("%pg: error: unsupported blocksize for dax\n", bdev);
@@ -137,49 +133,6 @@ bool generic_fsdax_supported(struct dax_device *dax_dev, 
		return false;

	}



	id = dax_read_lock();

	len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);

	len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);



	if (len < 1 || len2 < 1) {

		pr_info("%pg: error: dax access failed (%ld)\n",

				bdev, len < 1 ? len : len2);

		dax_read_unlock(id);

		return false;

	}



	if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) {

		/*

		 * An arch that has enabled the pmem api should also

		 * have its drivers support pfn_t_devmap()

		 *

		 * This is a developer warning and should not trigger in

		 * production. dax_flush() will crash since it depends

		 * on being able to do (page_address(pfn_to_page())).

		 */

		WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API));

		dax_enabled = true;

	} else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) {

		struct dev_pagemap *pgmap, *end_pgmap;



		pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL);

		end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL);

		if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX

				&& pfn_t_to_page(pfn)->pgmap == pgmap

				&& pfn_t_to_page(end_pfn)->pgmap == pgmap

				&& pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr))

				&& pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr)))

			dax_enabled = true;

		put_dev_pagemap(pgmap);

		put_dev_pagemap(end_pgmap);



	}

	dax_read_unlock(id);



	if (!dax_enabled) {

		pr_info("%pg: error: dax support not enabled\n", bdev);

		return false;

	}

	return true;

}

EXPORT_SYMBOL_GPL(generic_fsdax_supported);