libnvdimm: infrastructure for btt devices
NVDIMM namespaces, in addition to accepting "struct bio" based requests,
also have the capability to perform byte-aligned accesses. By default
only the bio/block interface is used. However, if another driver can
make effective use of the byte-aligned capability it can claim namespace
interface and use the byte-aligned ->rw_bytes() interface.
The BTT driver is the initial first consumer of this mechanism to allow
adding atomic sector update semantics to a pmem or blk namespace. This
patch is the sysfs infrastructure to allow configuring a BTT instance
for a namespace. Enabling that BTT and performing i/o is in a
subsequent patch.
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index ac21ce4..4fd9238 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -296,10 +296,28 @@
}
static DEVICE_ATTR_RO(namespace_seed);
+static ssize_t btt_seed_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct nd_region *nd_region = to_nd_region(dev);
+ ssize_t rc;
+
+ nvdimm_bus_lock(dev);
+ if (nd_region->btt_seed)
+ rc = sprintf(buf, "%s\n", dev_name(nd_region->btt_seed));
+ else
+ rc = sprintf(buf, "\n");
+ nvdimm_bus_unlock(dev);
+
+ return rc;
+}
+static DEVICE_ATTR_RO(btt_seed);
+
static struct attribute *nd_region_attributes[] = {
&dev_attr_size.attr,
&dev_attr_nstype.attr,
&dev_attr_mappings.attr,
+ &dev_attr_btt_seed.attr,
&dev_attr_set_cookie.attr,
&dev_attr_available_size.attr,
&dev_attr_namespace_seed.attr,
@@ -345,15 +363,18 @@
/*
* Upon successful probe/remove, take/release a reference on the
- * associated interleave set (if present)
+ * associated interleave set (if present), and plant new btt + namespace
+ * seeds.
*/
static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
struct device *dev, bool probe)
{
+ struct nd_region *nd_region;
+
if (!probe && (is_nd_pmem(dev) || is_nd_blk(dev))) {
- struct nd_region *nd_region = to_nd_region(dev);
int i;
+ nd_region = to_nd_region(dev);
for (i = 0; i < nd_region->ndr_mappings; i++) {
struct nd_mapping *nd_mapping = &nd_region->mapping[i];
struct nvdimm_drvdata *ndd = nd_mapping->ndd;
@@ -365,14 +386,21 @@
nd_mapping->ndd = NULL;
atomic_dec(&nvdimm->busy);
}
- } else if (dev->parent && is_nd_blk(dev->parent) && probe) {
- struct nd_region *nd_region = to_nd_region(dev->parent);
-
+ }
+ if (dev->parent && is_nd_blk(dev->parent) && probe) {
+ nd_region = to_nd_region(dev->parent);
nvdimm_bus_lock(dev);
if (nd_region->ns_seed == dev)
nd_region_create_blk_seed(nd_region);
nvdimm_bus_unlock(dev);
}
+ if (is_nd_btt(dev) && probe) {
+ nd_region = to_nd_region(dev->parent);
+ nvdimm_bus_lock(dev);
+ if (nd_region->btt_seed == dev)
+ nd_region_create_btt_seed(nd_region);
+ nvdimm_bus_unlock(dev);
+ }
}
void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev)
@@ -546,6 +574,7 @@
nd_region->provider_data = ndr_desc->provider_data;
nd_region->nd_set = ndr_desc->nd_set;
ida_init(&nd_region->ns_ida);
+ ida_init(&nd_region->btt_ida);
dev = &nd_region->dev;
dev_set_name(dev, "region%d", nd_region->id);
dev->parent = &nvdimm_bus->dev;