Section 5 about BTT's in kernel usage was quite obsolete,
replace it with a simple 'Usage' section that describes how
to set up a BTT namespace using the 'ndctl' utility.
Signed-off-by: Vishal Verma <vishal.l.verma(a)intel.com>
Documentation/nvdimm/btt.txt | 28 +++++++++-------------------
1 file changed, 9 insertions(+), 19 deletions(-)
diff --git a/Documentation/nvdimm/btt.txt b/Documentation/nvdimm/btt.txt
index b91443f..e293fb6 100644
@@ -256,28 +256,18 @@ If any of these error conditions are encountered, the arena is put
into a read
only state using a flag in the info block.
-5. In-kernel usage
-Any block driver that supports byte granularity IO to the storage may register
-with the BTT. It will have to provide the rw_bytes interface in its
+The BTT can be set up on any disk (namespace) exposed by the libnvdimm subsystem
+(pmem, or blk mode). The easiest way to set up such a namespace is using the
+'ndctl' utility :
- int (*rw_bytes)(struct gendisk *, void *, size_t, off_t, int rw);
+For example, the ndctl command line to setup a btt with a 4k sector size is:
-It may register with the BTT after it adds its own gendisk, using btt_init:
+ ndctl create-namespace -f -e namespace0.0 -m sector -l 4k
- struct btt *btt_init(struct gendisk *disk, unsigned long long rawsize,
- u32 lbasize, u8 uuid, int maxlane);
+See ndctl create-namespace --help for more options.
-note that maxlane is the maximum amount of concurrency the driver wishes to
-allow the BTT to use.
-The BTT 'disk' appears as a stacked block device that grabs the underlying block
-device in the O_EXCL mode.
-When the driver wishes to remove the backing disk, it should similarly call
-btt_fini using the same struct btt* handle that was provided to it by btt_init.
- void btt_fini(struct btt *btt);