[RFC PATCH 2/5] lib/memregion: Uplevel the pmem "region" ida to a global allocator

From: Dan Williams
Date: Thu Apr 04 2019 - 15:21:21 EST

In preparation for handling platform differentiated memory types beyond
persistent memory, uplevel the "region" identifier to a global number
space. This enables a device-dax instance to be registered to any memory
type with guaranteed unique names.

Cc: Keith Busch <keith.busch@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/nvdimm/Kconfig | 1 +
drivers/nvdimm/core.c | 1 -
drivers/nvdimm/nd-core.h | 1 -
drivers/nvdimm/region_devs.c | 13 ++++---------
include/linux/memregion.h | 6 ++++++
lib/Kconfig | 6 ++++++
lib/Makefile | 1 +
lib/memregion.c | 22 ++++++++++++++++++++++
8 files changed, 40 insertions(+), 11 deletions(-)
create mode 100644 include/linux/memregion.h
create mode 100644 lib/memregion.c

diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index 5e27918e4624..bf26cc5f6d67 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -3,6 +3,7 @@ menuconfig LIBNVDIMM
depends on PHYS_ADDR_T_64BIT
depends on HAS_IOMEM
depends on BLK_DEV
+ select MEMREGION
help
Generic support for non-volatile memory devices including
ACPI-6-NFIT defined resources. On platforms that define an
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index acce050856a8..75fe651d327d 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -463,7 +463,6 @@ static __exit void libnvdimm_exit(void)
nd_region_exit();
nvdimm_exit();
nvdimm_bus_exit();
- nd_region_devs_exit();
nvdimm_devs_exit();
}

diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index e5ffd5733540..17561302dfec 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -133,7 +133,6 @@ struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev);
int __init nvdimm_bus_init(void);
void nvdimm_bus_exit(void);
void nvdimm_devs_exit(void);
-void nd_region_devs_exit(void);
void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev);
struct nd_region;
void nd_region_create_ns_seed(struct nd_region *nd_region);
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index b4ef7d9ff22e..eefdfd2565dd 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -11,6 +11,7 @@
* General Public License for more details.
*/
#include <linux/scatterlist.h>
+#include <linux/memregion.h>
#include <linux/highmem.h>
#include <linux/sched.h>
#include <linux/slab.h>
@@ -27,7 +28,6 @@
*/
#include <linux/io-64-nonatomic-hi-lo.h>

-static DEFINE_IDA(region_ida);
static DEFINE_PER_CPU(int, flush_idx);

static int nvdimm_map_flush(struct device *dev, struct nvdimm *nvdimm, int dimm,
@@ -141,7 +141,7 @@ 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);
+ memregion_free(nd_region->id);
if (is_nd_blk(dev))
kfree(to_nd_blk_region(dev));
else
@@ -1036,7 +1036,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,

if (!region_buf)
return NULL;
- nd_region->id = ida_simple_get(&region_ida, 0, 0, GFP_KERNEL);
+ nd_region->id = memregion_alloc();
if (nd_region->id < 0)
goto err_id;

@@ -1090,7 +1090,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
return nd_region;

err_percpu:
- ida_simple_remove(&region_ida, nd_region->id);
+ memregion_free(nd_region->id);
err_id:
kfree(region_buf);
return NULL;
@@ -1237,8 +1237,3 @@ int nd_region_conflict(struct nd_region *nd_region, resource_size_t start,

return device_for_each_child(&nvdimm_bus->dev, &ctx, region_conflict);
}
-
-void __exit nd_region_devs_exit(void)
-{
- ida_destroy(&region_ida);
-}
diff --git a/include/linux/memregion.h b/include/linux/memregion.h
new file mode 100644
index 000000000000..99fa47793b49
--- /dev/null
+++ b/include/linux/memregion.h
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef _MEMREGION_H_
+#define _MEMREGION_H_
+int memregion_alloc(void);
+void memregion_free(int id);
+#endif /* _MEMREGION_H_ */
diff --git a/lib/Kconfig b/lib/Kconfig
index a9e56539bd11..0b765d9a1145 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -318,6 +318,12 @@ config DECOMPRESS_LZ4
config GENERIC_ALLOCATOR
bool

+#
+# Generic IDA for memory regions
+#
+config MEMREGION
+ bool
+
#
# reed solomon support is select'ed if needed
#
diff --git a/lib/Makefile b/lib/Makefile
index 3b08673e8881..6e237c4071af 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -122,6 +122,7 @@ obj-$(CONFIG_LIBCRC32C) += libcrc32c.o
obj-$(CONFIG_CRC8) += crc8.o
obj-$(CONFIG_XXHASH) += xxhash.o
obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
+obj-$(CONFIG_MEMREGION) += memregion.o

obj-$(CONFIG_842_COMPRESS) += 842/
obj-$(CONFIG_842_DECOMPRESS) += 842/
diff --git a/lib/memregion.c b/lib/memregion.c
new file mode 100644
index 000000000000..21f5ff96c2eb
--- /dev/null
+++ b/lib/memregion.c
@@ -0,0 +1,22 @@
+#include <linux/idr.h>
+#include <linux/module.h>
+
+static DEFINE_IDA(region_ida);
+
+int memregion_alloc(void)
+{
+ return ida_simple_get(&region_ida, 0, 0, GFP_KERNEL);
+}
+EXPORT_SYMBOL(memregion_alloc);
+
+void memregion_free(int id)
+{
+ ida_simple_remove(&region_ida, id);
+}
+EXPORT_SYMBOL(memregion_free);
+
+static void __exit memregion_exit(void)
+{
+ ida_destroy(&region_ida);
+}
+module_exit(memregion_exit);