Re: [PATCH RFC 10/10] nvdimm/e820: add multiple namespaces support

From: Barret Rhoden
Date: Tue Feb 04 2020 - 10:28:45 EST

Hi -

On 1/10/20 2:03 PM, Joao Martins wrote:
User can define regions with 'memmap=size!offset' which in turn
creates PMEM legacy devices. But because it is a label-less
NVDIMM device we only have one namespace for the whole device.

Add support for multiple namespaces by adding ndctl control
support, and exposing a minimal set of features:
(ND_CMD_GET_CONFIG_SIZE, ND_CMD_GET_CONFIG_DATA,
ND_CMD_SET_CONFIG_DATA) alongside NDD_ALIASING because we can
store labels.

FWIW, I like this a lot. If we move away from using memmap in favor of efi_fake_mem, ideally we'd have the same support for full-fledged pmem/dax regions and namespaces that this patch brings.

Thanks,
Barret



Initialization is a little different: We allocate and register an
nvdimm bus with an @nvdimm_descriptor which we use to locate
where we are keeping our label storage area. The config data
get/set/size operations are then simply memcpying to this area.

Equivalent approach can also be found in the NFIT tests which
emulate the same thing.

Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
drivers/nvdimm/e820.c | 212 +++++++++++++++++++++++++++++++++++++-----
1 file changed, 191 insertions(+), 21 deletions(-)

diff --git a/drivers/nvdimm/e820.c b/drivers/nvdimm/e820.c
index e02f60ad6c99..36fbff3d7110 100644
--- a/drivers/nvdimm/e820.c
+++ b/drivers/nvdimm/e820.c
@@ -7,14 +7,21 @@
#include <linux/memory_hotplug.h>
#include <linux/libnvdimm.h>
#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/ndctl.h>
+#include <linux/nd.h>
-static int e820_pmem_remove(struct platform_device *pdev)
-{
- struct nvdimm_bus *nvdimm_bus = platform_get_drvdata(pdev);
+#define LABEL_SIZE SZ_128K
- nvdimm_bus_unregister(nvdimm_bus);
- return 0;
-}
+struct e820_descriptor {
+ struct nd_interleave_set nd_set;
+ struct nvdimm_bus_descriptor nd_desc;
+ void *label;
+ unsigned char cookie1[16];
+ unsigned char cookie2[16];
+ struct nvdimm_bus *nvdimm_bus;
+ struct nvdimm *nvdimm;
+};
#ifdef CONFIG_MEMORY_HOTPLUG
static int e820_range_to_nid(resource_size_t addr)
@@ -28,43 +35,206 @@ static int e820_range_to_nid(resource_size_t addr)
}
#endif
+static int e820_get_config_size(struct nd_cmd_get_config_size *nd_cmd,
+ unsigned int buf_len)
+{
+ if (buf_len < sizeof(*nd_cmd))
+ return -EINVAL;
+
+ nd_cmd->status = 0;
+ nd_cmd->config_size = LABEL_SIZE;
+ nd_cmd->max_xfer = SZ_4K;
+
+ return 0;
+}
+
+static int e820_get_config_data(struct nd_cmd_get_config_data_hdr
+ *nd_cmd, unsigned int buf_len, void *label)
+{
+ unsigned int len, offset = nd_cmd->in_offset;
+ int rc;
+
+ if (buf_len < sizeof(*nd_cmd))
+ return -EINVAL;
+ if (offset >= LABEL_SIZE)
+ return -EINVAL;
+ if (nd_cmd->in_length + sizeof(*nd_cmd) > buf_len)
+ return -EINVAL;
+
+ nd_cmd->status = 0;
+ len = min(nd_cmd->in_length, LABEL_SIZE - offset);
+ memcpy(nd_cmd->out_buf, label + offset, len);
+ rc = buf_len - sizeof(*nd_cmd) - len;
+
+ return rc;
+}
+
+static int e820_set_config_data(struct nd_cmd_set_config_hdr *nd_cmd,
+ unsigned int buf_len, void *label)
+{
+ unsigned int len, offset = nd_cmd->in_offset;
+ u32 *status;
+ int rc;
+
+ if (buf_len < sizeof(*nd_cmd))
+ return -EINVAL;
+ if (offset >= LABEL_SIZE)
+ return -EINVAL;
+ if (nd_cmd->in_length + sizeof(*nd_cmd) + 4 > buf_len)
+ return -EINVAL;
+
+ status = (void *)nd_cmd + nd_cmd->in_length + sizeof(*nd_cmd);
+ *status = 0;
+ len = min(nd_cmd->in_length, LABEL_SIZE - offset);
+ memcpy(label + offset, nd_cmd->in_buf, len);
+ rc = buf_len - sizeof(*nd_cmd) - (len + 4);
+
+ return rc;
+}
+
+static struct e820_descriptor *to_e820_desc(struct nvdimm_bus_descriptor *desc)
+{
+ return container_of(desc, struct e820_descriptor, nd_desc);
+}
+
+static int e820_ndctl(struct nvdimm_bus_descriptor *nd_desc,
+ struct nvdimm *nvdimm, unsigned int cmd, void *buf,
+ unsigned int buf_len, int *cmd_rc)
+{
+ struct e820_descriptor *t = to_e820_desc(nd_desc);
+ int rc = -EINVAL;
+
+ switch (cmd) {
+ case ND_CMD_GET_CONFIG_SIZE:
+ rc = e820_get_config_size(buf, buf_len);
+ break;
+ case ND_CMD_GET_CONFIG_DATA:
+ rc = e820_get_config_data(buf, buf_len, t->label);
+ break;
+ case ND_CMD_SET_CONFIG_DATA:
+ rc = e820_set_config_data(buf, buf_len, t->label);
+ break;
+ default:
+ return rc;
+ }
+
+ return rc;
+}
+
+static void e820_desc_free(struct e820_descriptor *desc)
+{
+ if (!desc)
+ return;
+
+ nvdimm_bus_unregister(desc->nvdimm_bus);
+ kfree(desc->label);
+ kfree(desc);
+}
+
+static struct e820_descriptor *e820_desc_alloc(struct platform_device *pdev)
+{
+ struct nvdimm_bus_descriptor *nd_desc;
+ unsigned int cmd_mask, dimm_flags;
+ struct device *dev = &pdev->dev;
+ struct nvdimm_bus *nvdimm_bus;
+ struct e820_descriptor *desc;
+ struct nvdimm *nvdimm;
+
+ desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+ if (!desc)
+ goto err;
+
+ desc->label = kzalloc(LABEL_SIZE, GFP_KERNEL);
+ if (!desc->label)
+ goto err;
+
+ nd_desc = &desc->nd_desc;
+ nd_desc->provider_name = "e820";
+ nd_desc->module = THIS_MODULE;
+ nd_desc->ndctl = e820_ndctl;
+ nvdimm_bus = nvdimm_bus_register(&pdev->dev, nd_desc);
+ if (!nvdimm_bus) {
+ dev_err(dev, "nvdimm bus registration failure\n");
+ goto err;
+ }
+ desc->nvdimm_bus = nvdimm_bus;
+
+ cmd_mask = (1UL << ND_CMD_GET_CONFIG_SIZE |
+ 1UL << ND_CMD_GET_CONFIG_DATA |
+ 1UL << ND_CMD_SET_CONFIG_DATA);
+ dimm_flags = (1UL << NDD_ALIASING);
+ nvdimm = nvdimm_create(nvdimm_bus, pdev, NULL,
+ dimm_flags, cmd_mask, 0, NULL);
+ if (!nvdimm) {
+ dev_err(dev, "nvdimm creation failure\n");
+ goto err;
+ }
+ desc->nvdimm = nvdimm;
+ return desc;
+
+err:
+ e820_desc_free(desc);
+ return NULL;
+}
+
static int e820_register_one(struct resource *res, void *data)
{
+ struct platform_device *pdev = data;
struct nd_region_desc ndr_desc;
- struct nvdimm_bus *nvdimm_bus = data;
+ struct nd_mapping_desc mapping;
+ struct e820_descriptor *desc;
+
+ desc = e820_desc_alloc(pdev);
+ if (!desc)
+ return -ENOMEM;
+
+ mapping.nvdimm = desc->nvdimm;
+ mapping.start = res->start;
+ mapping.size = resource_size(res);
+ mapping.position = 0;
+
+ generate_random_uuid(desc->cookie1);
+ desc->nd_set.cookie1 = (u64) desc->cookie1;
+ generate_random_uuid(desc->cookie2);
+ desc->nd_set.cookie2 = (u64) desc->cookie2;
memset(&ndr_desc, 0, sizeof(ndr_desc));
ndr_desc.res = res;
ndr_desc.numa_node = e820_range_to_nid(res->start);
ndr_desc.target_node = ndr_desc.numa_node;
+ ndr_desc.mapping = &mapping;
+ ndr_desc.num_mappings = 1;
+ ndr_desc.nd_set = &desc->nd_set;
set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
- if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
+ if (!nvdimm_pmem_region_create(desc->nvdimm_bus, &ndr_desc)) {
+ e820_desc_free(desc);
+ dev_err(&pdev->dev, "nvdimm region creation failure\n");
return -ENXIO;
+ }
+
+ platform_set_drvdata(pdev, desc);
+ return 0;
+}
+
+static int e820_pmem_remove(struct platform_device *pdev)
+{
+ struct e820_descriptor *desc = platform_get_drvdata(pdev);
+
+ e820_desc_free(desc);
return 0;
}
static int e820_pmem_probe(struct platform_device *pdev)
{
- static struct nvdimm_bus_descriptor nd_desc;
- struct device *dev = &pdev->dev;
- struct nvdimm_bus *nvdimm_bus;
int rc = -ENXIO;
- nd_desc.provider_name = "e820";
- nd_desc.module = THIS_MODULE;
- nvdimm_bus = nvdimm_bus_register(dev, &nd_desc);
- if (!nvdimm_bus)
- goto err;
- platform_set_drvdata(pdev, nvdimm_bus);
-
rc = walk_iomem_res_desc(IORES_DESC_PERSISTENT_MEMORY_LEGACY,
- IORESOURCE_MEM, 0, -1, nvdimm_bus, e820_register_one);
+ IORESOURCE_MEM, 0, -1, pdev, e820_register_one);
if (rc)
goto err;
return 0;
err:
- nvdimm_bus_unregister(nvdimm_bus);
- dev_err(dev, "failed to register legacy persistent memory ranges\n");
+ dev_err(&pdev->dev, "failed to register legacy persistent memory ranges\n");
return rc;
}