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SubjectRe: [PATCH RFC 10/10] nvdimm/e820: add multiple namespaces support
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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@oracle.com>
> ---
> 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;
> }
>
>

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