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dm: Call proper helper to determine dax support

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DM was calling generic_fsdax_supported() to determine whether a device
referenced in the DM table supports DAX. However this is a helper for "leaf" device drivers so that
they don't have to duplicate common generic checks. High level code
should call dax_supported() helper which that calls into appropriate
helper for the particular device. This problem manifested itself as
kernel messages:

dm-3: error: dax access failed (-95)

when lvm2-testsuite run in cases where a DM device was stacked on top of
another DM device.

Fixes: 7bf7eac8d6 ("dax: Arrange for dax_supported check to span multiple devices")
Cc: <stable@vger.kernel.org>
Tested-by: Adrian Huang <ahuang12@lenovo.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/160061715195.13131.5503173247632041975.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Jan Kara 2020-09-20 08:54:42 -07:00 committed by Dan Williams
parent 02186d8897
commit e2ec512825
3 changed files with 31 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/dax/super.c
View File

@ -325,11 +325,15 @@ EXPORT_SYMBOL_GPL(dax_direct_access);
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len)
{
if (!dax_dev)
return false;
if (!dax_alive(dax_dev))
return false;
return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
}
EXPORT_SYMBOL_GPL(dax_supported);
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i)

10
drivers/md/dm-table.c
View File

@ -860,10 +860,14 @@ EXPORT_SYMBOL_GPL(dm_table_set_type);
int device_supports_dax(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
int blocksize = *(int *) data;
int blocksize = *(int *) data, id;
bool rc;
return generic_fsdax_supported(dev->dax_dev, dev->bdev, blocksize,
start, len);
id = dax_read_lock();
rc = dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);
dax_read_unlock(id);
return rc;
}
/* Check devices support synchronous DAX */

22
include/linux/dax.h
View File

@ -130,6 +130,8 @@ static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
sectors);
}
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len);
static inline void fs_put_dax(struct dax_device *dax_dev)
{
@ -157,6 +159,13 @@ static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
return false;
}
static inline bool dax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t len)
{
return false;
}
static inline void fs_put_dax(struct dax_device *dax_dev)
{
}
@ -189,14 +198,23 @@ static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
}
#endif
#if IS_ENABLED(CONFIG_DAX)
int dax_read_lock(void);
void dax_read_unlock(int id);
#else
static inline int dax_read_lock(void)
{
return 0;
}
static inline void dax_read_unlock(int id)
{
}
#endif /* CONFIG_DAX */
bool dax_alive(struct dax_device *dax_dev);
void *dax_get_private(struct dax_device *dax_dev);
long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
void **kaddr, pfn_t *pfn);
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len);
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i);
size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,