libnvdimm, pmem: direct map legacy pmem by default

The expectation is that the legacy / non-standard pmem discovery method
(e820 type-12) will only ever be used to describe small quantities of
persistent memory.  Larger capacities will be described via the ACPI
NFIT.  When "allocate struct page from pmem" support is added this default
policy can be overridden by assigning a legacy pmem namespace to a pfn
device, however this would be only be necessary if a platform used the
legacy mechanism to define a very large range.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/nvdimm/e820.c b/drivers/nvdimm/e820.c
index 1b5743ad92db3da825c521f18d93a1b729ec1c4b..8282db2ef99ea02077ef5609b85acfe0a8aae823 100644 (file)
--- a/drivers/nvdimm/e820.c
+++ b/drivers/nvdimm/e820.c
@@ -49,6 +49,7 @@ static int e820_pmem_probe(struct platform_device *pdev)
                ndr_desc.res = p;
                ndr_desc.attr_groups = e820_pmem_region_attribute_groups;
                ndr_desc.numa_node = NUMA_NO_NODE;
+               set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
                if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
                        goto err;
        }

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 9303ca29be9b6e337340faf7bcd4e57b2414fb3c..0955b2cb10fe87ec17cac82ac60eeedac54fb3b5 100644 (file)
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/slab.h>
+#include <linux/pmem.h>
 #include <linux/nd.h>
 #include "nd-core.h"
 #include "nd.h"
@@ -76,11 +77,32 @@ static bool is_namespace_io(struct device *dev)
        return dev ? dev->type == &namespace_io_device_type : false;
 }
 
+bool pmem_should_map_pages(struct device *dev)
+{
+       struct nd_region *nd_region = to_nd_region(dev->parent);
+
+       if (!IS_ENABLED(CONFIG_ZONE_DEVICE))
+               return false;
+
+       if (!test_bit(ND_REGION_PAGEMAP, &nd_region->flags))
+               return false;
+
+       if (is_nd_pfn(dev) || is_nd_btt(dev))
+               return false;
+
+#ifdef ARCH_MEMREMAP_PMEM
+       return ARCH_MEMREMAP_PMEM == MEMREMAP_WB;
+#else
+       return false;
+#endif
+}
+EXPORT_SYMBOL(pmem_should_map_pages);
+
 const char *nvdimm_namespace_disk_name(struct nd_namespace_common *ndns,
                char *name)
 {
        struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
-       const char *suffix = "";
+       const char *suffix = NULL;
 
        if (ndns->claim) {
                if (is_nd_btt(ndns->claim))
@@ -93,13 +115,16 @@ const char *nvdimm_namespace_disk_name(struct nd_namespace_common *ndns,
                                        dev_name(ndns->claim));
        }
 
-       if (is_namespace_pmem(&ndns->dev) || is_namespace_io(&ndns->dev))
-               sprintf(name, "pmem%d%s", nd_region->id, suffix);
-       else if (is_namespace_blk(&ndns->dev)) {
+       if (is_namespace_pmem(&ndns->dev) || is_namespace_io(&ndns->dev)) {
+               if (!suffix && pmem_should_map_pages(&ndns->dev))
+                       suffix = "m";
+               sprintf(name, "pmem%d%s", nd_region->id, suffix ? suffix : "");
+       } else if (is_namespace_blk(&ndns->dev)) {
                struct nd_namespace_blk *nsblk;
 
                nsblk = to_nd_namespace_blk(&ndns->dev);
-               sprintf(name, "ndblk%d.%d%s", nd_region->id, nsblk->id, suffix);
+               sprintf(name, "ndblk%d.%d%s", nd_region->id, nsblk->id,
+                               suffix ? suffix : "");
        } else {
                return NULL;
        }

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 83e5d09350123bceab6c02d63c122567df7d8ca4..417e521d299cb4645f5739f7608cc2d0d84a701c 100644 (file)
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -100,6 +100,7 @@ struct nd_region {
        struct ida ns_ida;
        struct ida btt_ida;
        struct ida pfn_ida;
+       unsigned long flags;
        struct device *ns_seed;
        struct device *btt_seed;
        struct device *pfn_seed;
@@ -276,4 +277,5 @@ static inline bool nd_iostat_start(struct bio *bio, unsigned long *start)
 void nd_iostat_end(struct bio *bio, unsigned long start);
 resource_size_t nd_namespace_blk_validate(struct nd_namespace_blk *nsblk);
 const u8 *nd_dev_to_uuid(struct device *dev);
+bool pmem_should_map_pages(struct device *dev);
 #endif /* __ND_H__ */

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 2f885e5d9c365182044e57e84894992629e8e6bc..c5ae2e579288247c6e61f3b1cce468477a83b5ba 100644 (file)
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -148,9 +148,18 @@ static struct pmem_device *pmem_alloc(struct device *dev,
                return ERR_PTR(-EBUSY);
        }
 
-       pmem->virt_addr = memremap_pmem(dev, pmem->phys_addr, pmem->size);
-       if (!pmem->virt_addr)
-               return ERR_PTR(-ENXIO);
+       if (pmem_should_map_pages(dev)) {
+               void *addr = devm_memremap_pages(dev, res);
+
+               if (IS_ERR(addr))
+                       return addr;
+               pmem->virt_addr = (void __pmem *) addr;
+       } else {
+               pmem->virt_addr = memremap_pmem(dev, pmem->phys_addr,
+                               pmem->size);
+               if (!pmem->virt_addr)
+                       return ERR_PTR(-ENXIO);
+       }
 
        return pmem;
 }

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index da4338154ad21939b3800abb60136b6719f315d0..529f3f02e7b2d90ee989e88d400aa1bb4f5f0500 100644 (file)
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -758,6 +758,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
        nd_region->provider_data = ndr_desc->provider_data;
        nd_region->nd_set = ndr_desc->nd_set;
        nd_region->num_lanes = ndr_desc->num_lanes;
+       nd_region->flags = ndr_desc->flags;
        nd_region->ro = ro;
        nd_region->numa_node = ndr_desc->numa_node;
        ida_init(&nd_region->ns_ida);

diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 75e3af01ee325840e3165919ab3a8fd42d76451f..3f021dc5da8c34e59768dca61dda323035368c0f 100644 (file)
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -31,6 +31,9 @@ enum {
        ND_CMD_ARS_STATUS_MAX = SZ_4K,
        ND_MAX_MAPPINGS = 32,
 
+       /* region flag indicating to direct-map persistent memory by default */
+       ND_REGION_PAGEMAP = 0,
+
        /* mark newly adjusted resources as requiring a label update */
        DPA_RESOURCE_ADJUSTED = 1 << 0,
 };
@@ -91,6 +94,7 @@ struct nd_region_desc {
        void *provider_data;
        int num_lanes;
        int numa_node;
+       unsigned long flags;
 };
 
 struct nvdimm_bus;