nd_pmem attaches to persistent memory regions and namespaces emitted by
the nd subsystem, and, same as the original pmem driver, presents the
system-physical-address range as a block device.

Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Boaz Harrosh <b...@plexistor.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Jens Axboe <ax...@fb.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Christoph Hellwig <h...@lst.de>
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 drivers/block/Kconfig     |   11 -------
 drivers/block/Makefile    |    1 -
 drivers/block/nd/Kconfig  |   17 +++++++++++
 drivers/block/nd/Makefile |    3 ++
 drivers/block/nd/pmem.c   |   72 +++++++++++++++++++++++++++++++++++++++------
 5 files changed, 83 insertions(+), 21 deletions(-)
 rename drivers/block/{pmem.c => nd/pmem.c} (81%)

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index dfe40e5ca9bd..1cef4ffb16c5 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -406,17 +406,6 @@ config BLK_DEV_RAM_DAX
          and will prevent RAM block device backing store memory from being
          allocated from highmem (only a problem for highmem systems).
 
-config BLK_DEV_PMEM
-       tristate "Persistent memory block device support"
-       help
-         Saying Y here will allow you to use a contiguous range of reserved
-         memory as one or more persistent block devices.
-
-         To compile this driver as a module, choose M here: the module will be
-         called 'pmem'.
-
-         If unsure, say N.
-
 config CDROM_PKTCDVD
        tristate "Packet writing on CD/DVD media"
        depends on !UML
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 18b27bb9cd2d..3a2f15be66a3 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -14,7 +14,6 @@ obj-$(CONFIG_PS3_VRAM)                += ps3vram.o
 obj-$(CONFIG_ATARI_FLOPPY)     += ataflop.o
 obj-$(CONFIG_AMIGA_Z2RAM)      += z2ram.o
 obj-$(CONFIG_BLK_DEV_RAM)      += brd.o
-obj-$(CONFIG_BLK_DEV_PMEM)     += pmem.o
 obj-$(CONFIG_BLK_DEV_LOOP)     += loop.o
 obj-$(CONFIG_BLK_CPQ_DA)       += cpqarray.o
 obj-$(CONFIG_BLK_CPQ_CISS_DA)  += cciss.o
diff --git a/drivers/block/nd/Kconfig b/drivers/block/nd/Kconfig
index 6c15d10bf4e0..38eae5f0ae4b 100644
--- a/drivers/block/nd/Kconfig
+++ b/drivers/block/nd/Kconfig
@@ -72,4 +72,21 @@ config NFIT_TEST
 
          Say N unless you are doing development of the 'nd' subsystem.
 
+config BLK_DEV_PMEM
+       tristate "PMEM: Persistent memory block device support"
+       depends on ND_CORE || X86_PMEM_LEGACY
+       default ND_CORE
+       help
+         Memory ranges for PMEM are described by either an NFIT
+         (NVDIMM Firmware Interface Table, see CONFIG_NFIT_ACPI), a
+         non-standard OEM-specific E820 memory type (type-12, see
+         CONFIG_X86_PMEM_LEGACY), or it is manually specified by the
+         'memmap=nn[KMG]!ss[KMG]' kernel command line (see
+         Documentation/kernel-parameters.txt).  This driver converts
+         these persistent memory ranges into block devices that are
+         capable of DAX (direct-access) file system mappings.  See
+         Documentation/blockdev/nd.txt for more details.
+
+         Say Y if you want to use a NVDIMM described by NFIT
+
 endif
diff --git a/drivers/block/nd/Makefile b/drivers/block/nd/Makefile
index 769ddc34f974..c0194d52e5ad 100644
--- a/drivers/block/nd/Makefile
+++ b/drivers/block/nd/Makefile
@@ -16,6 +16,7 @@ endif
 
 obj-$(CONFIG_ND_CORE) += nd.o
 obj-$(CONFIG_NFIT_ACPI) += nd_acpi.o
+obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o
 
 nd_acpi-y := acpi.o
 
@@ -26,3 +27,5 @@ nd-y += dimm.o
 nd-y += region_devs.o
 nd-y += region.o
 nd-y += namespace_devs.o
+
+nd_pmem-y := pmem.o
diff --git a/drivers/block/pmem.c b/drivers/block/nd/pmem.c
similarity index 81%
rename from drivers/block/pmem.c
rename to drivers/block/nd/pmem.c
index eabf4a8d0085..cd83a9a98d89 100644
--- a/drivers/block/pmem.c
+++ b/drivers/block/nd/pmem.c
@@ -1,7 +1,7 @@
 /*
  * Persistent Memory Driver
  *
- * Copyright (c) 2014, Intel Corporation.
+ * Copyright (c) 2014-2015, Intel Corporation.
  * Copyright (c) 2015, Christoph Hellwig <h...@lst.de>.
  * Copyright (c) 2015, Boaz Harrosh <b...@plexistor.com>.
  *
@@ -23,6 +23,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/slab.h>
+#include <linux/nd.h>
 
 #define PMEM_MINORS            16
 
@@ -34,10 +35,11 @@ struct pmem_device {
        phys_addr_t             phys_addr;
        void                    *virt_addr;
        size_t                  size;
+       int                     id;
 };
 
 static int pmem_major;
-static atomic_t pmem_index;
+static DEFINE_IDA(pmem_ida);
 
 static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
                        unsigned int len, unsigned int off, int rw,
@@ -122,20 +124,26 @@ static struct pmem_device *pmem_alloc(struct device *dev, 
struct resource *res)
 {
        struct pmem_device *pmem;
        struct gendisk *disk;
-       int idx, err;
+       int err;
 
        err = -ENOMEM;
        pmem = kzalloc(sizeof(*pmem), GFP_KERNEL);
        if (!pmem)
                goto out;
 
+       pmem->id = ida_simple_get(&pmem_ida, 0, 0, GFP_KERNEL);
+       if (pmem->id < 0) {
+               err = pmem->id;
+               goto out_free_dev;
+       }
+
        pmem->phys_addr = res->start;
        pmem->size = resource_size(res);
 
        err = -EINVAL;
        if (!request_mem_region(pmem->phys_addr, pmem->size, "pmem")) {
                dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n", 
&pmem->phys_addr, pmem->size);
-               goto out_free_dev;
+               goto out_free_ida;
        }
 
        /*
@@ -159,15 +167,13 @@ static struct pmem_device *pmem_alloc(struct device *dev, 
struct resource *res)
        if (!disk)
                goto out_free_queue;
 
-       idx = atomic_inc_return(&pmem_index) - 1;
-
        disk->major             = pmem_major;
-       disk->first_minor       = PMEM_MINORS * idx;
+       disk->first_minor       = PMEM_MINORS * pmem->id;
        disk->fops              = &pmem_fops;
        disk->private_data      = pmem;
        disk->queue             = pmem->pmem_queue;
        disk->flags             = GENHD_FL_EXT_DEVT;
-       sprintf(disk->disk_name, "pmem%d", idx);
+       sprintf(disk->disk_name, "pmem%d", pmem->id);
        disk->driverfs_dev = dev;
        set_capacity(disk, pmem->size >> 9);
        pmem->pmem_disk = disk;
@@ -182,6 +188,8 @@ out_unmap:
        iounmap(pmem->virt_addr);
 out_release_region:
        release_mem_region(pmem->phys_addr, pmem->size);
+out_free_ida:
+       ida_simple_remove(&pmem_ida, pmem->id);
 out_free_dev:
        kfree(pmem);
 out:
@@ -195,6 +203,7 @@ static void pmem_free(struct pmem_device *pmem)
        blk_cleanup_queue(pmem->pmem_queue);
        iounmap(pmem->virt_addr);
        release_mem_region(pmem->phys_addr, pmem->size);
+       ida_simple_remove(&pmem_ida, pmem->id);
        kfree(pmem);
 }
 
@@ -236,6 +245,39 @@ static struct platform_driver pmem_driver = {
        },
 };
 
+static int nd_pmem_probe(struct device *dev)
+{
+       struct nd_namespace_io *nsio = to_nd_namespace_io(dev);
+       struct pmem_device *pmem;
+
+       pmem = pmem_alloc(dev, &nsio->res);
+       if (IS_ERR(pmem))
+               return PTR_ERR(pmem);
+
+       dev_set_drvdata(dev, pmem);
+
+       return 0;
+}
+
+static int nd_pmem_remove(struct device *dev)
+{
+       struct pmem_device *pmem = dev_get_drvdata(dev);
+
+       pmem_free(pmem);
+       return 0;
+}
+
+MODULE_ALIAS("pmem");
+MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
+static struct nd_device_driver nd_pmem_driver = {
+       .probe = nd_pmem_probe,
+       .remove = nd_pmem_remove,
+       .drv = {
+               .name = "pmem",
+       },
+       .type = ND_DRIVER_NAMESPACE_IO,
+};
+
 static int __init pmem_init(void)
 {
        int error;
@@ -244,9 +286,20 @@ static int __init pmem_init(void)
        if (pmem_major < 0)
                return pmem_major;
 
+       error = nd_driver_register(&nd_pmem_driver);
+       if (error)
+               goto out_unregister_blkdev;
+
        error = platform_driver_register(&pmem_driver);
        if (error)
-               unregister_blkdev(pmem_major, "pmem");
+               goto out_unregister_nd;
+
+       return 0;
+
+ out_unregister_nd:
+       driver_unregister(&nd_pmem_driver.drv);
+ out_unregister_blkdev:
+       unregister_blkdev(pmem_major, "pmem");
        return error;
 }
 module_init(pmem_init);
@@ -254,6 +307,7 @@ module_init(pmem_init);
 static void pmem_exit(void)
 {
        platform_driver_unregister(&pmem_driver);
+       driver_unregister(&nd_pmem_driver.drv);
        unregister_blkdev(pmem_major, "pmem");
 }
 module_exit(pmem_exit);

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