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path: root/drivers/nvdimm/region_devs.c
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Diffstat (limited to 'drivers/nvdimm/region_devs.c')
-rw-r--r--drivers/nvdimm/region_devs.c82
1 files changed, 78 insertions, 4 deletions
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 4fd92389fa7e..fe8ec21fe3d7 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -32,6 +32,7 @@ static void nd_region_release(struct device *dev)
put_device(&nvdimm->dev);
}
+ free_percpu(nd_region->lane);
ida_simple_remove(&region_ida, nd_region->id);
kfree(nd_region);
}
@@ -531,13 +532,66 @@ void *nd_region_provider_data(struct nd_region *nd_region)
}
EXPORT_SYMBOL_GPL(nd_region_provider_data);
+/**
+ * nd_region_acquire_lane - allocate and lock a lane
+ * @nd_region: region id and number of lanes possible
+ *
+ * A lane correlates to a BLK-data-window and/or a log slot in the BTT.
+ * We optimize for the common case where there are 256 lanes, one
+ * per-cpu. For larger systems we need to lock to share lanes. For now
+ * this implementation assumes the cost of maintaining an allocator for
+ * free lanes is on the order of the lock hold time, so it implements a
+ * static lane = cpu % num_lanes mapping.
+ *
+ * In the case of a BTT instance on top of a BLK namespace a lane may be
+ * acquired recursively. We lock on the first instance.
+ *
+ * In the case of a BTT instance on top of PMEM, we only acquire a lane
+ * for the BTT metadata updates.
+ */
+unsigned int nd_region_acquire_lane(struct nd_region *nd_region)
+{
+ unsigned int cpu, lane;
+
+ cpu = get_cpu();
+ if (nd_region->num_lanes < nr_cpu_ids) {
+ struct nd_percpu_lane *ndl_lock, *ndl_count;
+
+ lane = cpu % nd_region->num_lanes;
+ ndl_count = per_cpu_ptr(nd_region->lane, cpu);
+ ndl_lock = per_cpu_ptr(nd_region->lane, lane);
+ if (ndl_count->count++ == 0)
+ spin_lock(&ndl_lock->lock);
+ } else
+ lane = cpu;
+
+ return lane;
+}
+EXPORT_SYMBOL(nd_region_acquire_lane);
+
+void nd_region_release_lane(struct nd_region *nd_region, unsigned int lane)
+{
+ if (nd_region->num_lanes < nr_cpu_ids) {
+ unsigned int cpu = get_cpu();
+ struct nd_percpu_lane *ndl_lock, *ndl_count;
+
+ ndl_count = per_cpu_ptr(nd_region->lane, cpu);
+ ndl_lock = per_cpu_ptr(nd_region->lane, lane);
+ if (--ndl_count->count == 0)
+ spin_unlock(&ndl_lock->lock);
+ put_cpu();
+ }
+ put_cpu();
+}
+EXPORT_SYMBOL(nd_region_release_lane);
+
static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
struct nd_region_desc *ndr_desc, struct device_type *dev_type,
const char *caller)
{
struct nd_region *nd_region;
struct device *dev;
- u16 i;
+ unsigned int i;
for (i = 0; i < ndr_desc->num_mappings; i++) {
struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
@@ -557,9 +611,19 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
if (!nd_region)
return NULL;
nd_region->id = ida_simple_get(&region_ida, 0, 0, GFP_KERNEL);
- if (nd_region->id < 0) {
- kfree(nd_region);
- return NULL;
+ if (nd_region->id < 0)
+ goto err_id;
+
+ nd_region->lane = alloc_percpu(struct nd_percpu_lane);
+ if (!nd_region->lane)
+ goto err_percpu;
+
+ for (i = 0; i < nr_cpu_ids; i++) {
+ struct nd_percpu_lane *ndl;
+
+ ndl = per_cpu_ptr(nd_region->lane, i);
+ spin_lock_init(&ndl->lock);
+ ndl->count = 0;
}
memcpy(nd_region->mapping, ndr_desc->nd_mapping,
@@ -573,6 +637,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
nd_region->ndr_mappings = ndr_desc->num_mappings;
nd_region->provider_data = ndr_desc->provider_data;
nd_region->nd_set = ndr_desc->nd_set;
+ nd_region->num_lanes = ndr_desc->num_lanes;
ida_init(&nd_region->ns_ida);
ida_init(&nd_region->btt_ida);
dev = &nd_region->dev;
@@ -585,11 +650,18 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
nd_device_register(dev);
return nd_region;
+
+ err_percpu:
+ ida_simple_remove(&region_ida, nd_region->id);
+ err_id:
+ kfree(nd_region);
+ return NULL;
}
struct nd_region *nvdimm_pmem_region_create(struct nvdimm_bus *nvdimm_bus,
struct nd_region_desc *ndr_desc)
{
+ ndr_desc->num_lanes = ND_MAX_LANES;
return nd_region_create(nvdimm_bus, ndr_desc, &nd_pmem_device_type,
__func__);
}
@@ -600,6 +672,7 @@ struct nd_region *nvdimm_blk_region_create(struct nvdimm_bus *nvdimm_bus,
{
if (ndr_desc->num_mappings > 1)
return NULL;
+ ndr_desc->num_lanes = min(ndr_desc->num_lanes, ND_MAX_LANES);
return nd_region_create(nvdimm_bus, ndr_desc, &nd_blk_device_type,
__func__);
}
@@ -608,6 +681,7 @@ EXPORT_SYMBOL_GPL(nvdimm_blk_region_create);
struct nd_region *nvdimm_volatile_region_create(struct nvdimm_bus *nvdimm_bus,
struct nd_region_desc *ndr_desc)
{
+ ndr_desc->num_lanes = ND_MAX_LANES;
return nd_region_create(nvdimm_bus, ndr_desc, &nd_volatile_device_type,
__func__);
}