[PATCH 05/29] dax: remove the pgmap sanity checks in generic_fsdax_supported

Christoph Hellwig
2021-11-09T08:33:36Z

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

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/dax/super.c | 49 +--------------------------------------------
1 file changed, 1 insertion(+), 48 deletions(-)

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 9383c11b21853..04fc680542e8d 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -107,13 +107,9 @@ 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);
@@ -138,49 +134,6 @@ 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);
--
2.30.2