diff options
author | Dan Williams <dan.j.williams@intel.com> | 2017-01-26 20:37:35 -0800 |
---|---|---|
committer | Dan Williams <dan.j.williams@intel.com> | 2017-04-20 11:57:52 -0700 |
commit | b0686260fecaa924d8eff2ace94bee70506bc308 (patch) | |
tree | 36193b32e9f64ee93c4dd02e29da9256e8930fb7 /drivers/dax | |
parent | d8f07aee3f2fd959878bf614d4e984900018eb9e (diff) | |
download | linux-b0686260fecaa924d8eff2ace94bee70506bc308.tar.bz2 |
dax: introduce dax_direct_access()
Replace bdev_direct_access() with dax_direct_access() that uses
dax_device and dax_operations instead of a block_device and
block_device_operations for dax. Once all consumers of the old api have
been converted bdev_direct_access() will be deleted.
Given that block device partitioning decisions can cause dax page
alignment constraints to be violated this also introduces the
bdev_dax_pgoff() helper. It handles calculating a logical pgoff relative
to the dax_device and also checks for page alignment.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dax')
-rw-r--r-- | drivers/dax/super.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 1a58542ee8fd..465dcd7317d5 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -65,6 +65,45 @@ struct dax_device { const struct dax_operations *ops; }; +/** + * dax_direct_access() - translate a device pgoff to an absolute pfn + * @dax_dev: a dax_device instance representing the logical memory range + * @pgoff: offset in pages from the start of the device to translate + * @nr_pages: number of consecutive pages caller can handle relative to @pfn + * @kaddr: output parameter that returns a virtual address mapping of pfn + * @pfn: output parameter that returns an absolute pfn translation of @pgoff + * + * Return: negative errno if an error occurs, otherwise the number of + * pages accessible at the device relative @pgoff. + */ +long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, + void **kaddr, pfn_t *pfn) +{ + long avail; + + /* + * The device driver is allowed to sleep, in order to make the + * memory directly accessible. + */ + might_sleep(); + + if (!dax_dev) + return -EOPNOTSUPP; + + if (!dax_alive(dax_dev)) + return -ENXIO; + + if (nr_pages < 0) + return nr_pages; + + avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, + kaddr, pfn); + if (!avail) + return -ERANGE; + return min(avail, nr_pages); +} +EXPORT_SYMBOL_GPL(dax_direct_access); + bool dax_alive(struct dax_device *dax_dev) { lockdep_assert_held(&dax_srcu); |