[PATCH v6 08/12] lib: Uplevel the pmem "region" ida to a global allocator

From: Dan Williams
Date: Wed Oct 09 2019 - 19:19:41 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 <kbusch@xxxxxxxxxx>
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 | 19 +++++++++++++++++++
lib/Kconfig | 3 +++
lib/Makefile | 1 +
lib/memregion.c | 18 ++++++++++++++++++
8 files changed, 46 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 36af7af6b7cf..b7d1eb38b27d 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -4,6 +4,7 @@ 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 9204f1e9fd14..e592c4964674 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -455,7 +455,6 @@ 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 25fa121104d0..aa059439fca0 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -114,7 +114,6 @@ 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);
struct nd_region;
void nd_region_advance_seeds(struct nd_region *nd_region, struct device *dev);
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 ef423ba1a711..fbf34cf688f4 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -3,6 +3,7 @@
* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
*/
#include <linux/scatterlist.h>
+#include <linux/memregion.h>
#include <linux/highmem.h>
#include <linux/sched.h>
#include <linux/slab.h>
@@ -19,7 +20,6 @@
*/
#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,
@@ -133,7 +133,7 @@ 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
@@ -985,7 +985,7 @@ 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(GFP_KERNEL);
if (nd_region->id < 0)
goto err_id;

@@ -1044,7 +1044,7 @@ 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;
@@ -1216,8 +1216,3 @@ 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..7de7c0a1444e
--- /dev/null
+++ b/include/linux/memregion.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _MEMREGION_H_
+#define _MEMREGION_H_
+#include <linux/types.h>
+#include <linux/errno.h>
+
+#ifdef CONFIG_MEMREGION
+int memregion_alloc(gfp_t gfp);
+void memregion_free(int id);
+#else
+static inline int memregion_alloc(gfp_t gfp)
+{
+ return -ENOMEM;
+}
+void memregion_free(int id)
+{
+}
+#endif
+#endif /* _MEMREGION_H_ */
diff --git a/lib/Kconfig b/lib/Kconfig
index 183f92a297ca..0dc043ac271d 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -606,6 +606,9 @@ config ARCH_NO_SG_CHAIN
config ARCH_HAS_PMEM_API
bool

+config MEMREGION
+ bool
+
# use memcpy to implement user copies for nommu architectures
config UACCESS_MEMCPY
bool
diff --git a/lib/Makefile b/lib/Makefile
index c5892807e06f..2fb7b47018f1 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -212,6 +212,7 @@ obj-$(CONFIG_GENERIC_NET_UTILS) += net_utils.o

obj-$(CONFIG_SG_SPLIT) += sg_split.o
obj-$(CONFIG_SG_POOL) += sg_pool.o
+obj-$(CONFIG_MEMREGION) += memregion.o
obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
obj-$(CONFIG_IRQ_POLL) += irq_poll.o

diff --git a/lib/memregion.c b/lib/memregion.c
new file mode 100644
index 000000000000..77c85b5251da
--- /dev/null
+++ b/lib/memregion.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* identifiers for device / performance-differentiated memory regions */
+#include <linux/idr.h>
+#include <linux/types.h>
+
+static DEFINE_IDA(memregion_ids);
+
+int memregion_alloc(gfp_t gfp)
+{
+ return ida_alloc(&memregion_ids, gfp);
+}
+EXPORT_SYMBOL(memregion_alloc);
+
+void memregion_free(int id)
+{
+ ida_free(&memregion_ids, id);
+}
+EXPORT_SYMBOL(memregion_free);