On Thu, 10 Jun 2021 15:26:26 -0700
Dan Williams <[email protected]> wrote:
> While a memX device on /sys/bus/cxl represents a CXL memory expander
> control interface, a pmemX device represents the persistent memory
> sub-functionality. It bridges the CXL subystem to the libnvdimm nmemX
> control interface.
>
> With this skeleton ndctl can now see persistent memory devices on a
> "CXL" bus. Later patches add support for translating libnvdimm native
> commands to CXL commands.
>
> # ndctl list -BDiu -b CXL
> {
> "provider":"CXL",
> "dev":"ndbus1",
> "dimms":[
> {
> "dev":"nmem1",
> "state":"disabled"
> },
> {
> "dev":"nmem0",
> "state":"disabled"
> }
> ]
> }
>
> Given nvdimm_bus_unregister() removes all devices on an ndbus0 the
> cxl_pmem infrastructure needs to arrange ->remove() to be triggered on
> cxl_nvdimm devices to keep their enabled state synchronized with the
> registration state of their corresponding device on the nvdimm_bus. In
> other words, always arrange for cxl_nvdimm_driver.remove() to unregister
> nvdimms from an nvdimm_bus ahead of the bus being unregistered.
>
> Signed-off-by: Dan Williams <[email protected]>
Being my usual fussy self, I've highlighed a few header changes that
as far as I can see are unrelated to this specific patch.
Otherwise, one request for a local variable name change and
a bit of trivial editorial stuff.
Thanks,
Jonathan
> ---
> drivers/cxl/core.c | 86 ++++++++++++++++++++++++++++++++++++++++
> drivers/cxl/cxl.h | 13 ++++++
> drivers/cxl/mem.h | 2 +
> drivers/cxl/pci.c | 23 ++++++++---
> drivers/cxl/pmem.c | 111
> +++++++++++++++++++++++++++++++++++++++++++++++-----
> 5 files changed, 217 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/cxl/core.c b/drivers/cxl/core.c
> index f0305c9c91c8..6db660249cea 100644
> --- a/drivers/cxl/core.c
> +++ b/drivers/cxl/core.c
> @@ -7,6 +7,7 @@
> #include <linux/slab.h>
> #include <linux/idr.h>
> #include "cxl.h"
> +#include "mem.h"
>
> /**
> * DOC: cxl core
> @@ -731,6 +732,89 @@ struct cxl_nvdimm_bridge
> *devm_cxl_add_nvdimm_bridge(struct device *host,
> }
> EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm_bridge);
>
> +static void cxl_nvdimm_release(struct device *dev)
> +{
> + struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
> +
> + kfree(cxl_nvd);
> +}
> +
> +static const struct attribute_group *cxl_nvdimm_attribute_groups[] = {
> + &cxl_base_attribute_group,
> + NULL,
> +};
> +
> +static const struct device_type cxl_nvdimm_type = {
> + .name = "cxl_nvdimm",
> + .release = cxl_nvdimm_release,
> + .groups = cxl_nvdimm_attribute_groups,
> +};
> +
> +bool is_cxl_nvdimm(struct device *dev)
> +{
> + return dev->type == &cxl_nvdimm_type;
> +}
> +EXPORT_SYMBOL_GPL(is_cxl_nvdimm);
> +
> +struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev)
> +{
> + if (dev_WARN_ONCE(dev, !is_cxl_nvdimm(dev),
> + "not a cxl_nvdimm device\n"))
> + return NULL;
> + return container_of(dev, struct cxl_nvdimm, dev);
> +}
> +EXPORT_SYMBOL_GPL(to_cxl_nvdimm);
> +
> +static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd)
> +{
> + struct cxl_nvdimm *cxl_nvd;
> + struct device *dev;
> +
> + cxl_nvd = kzalloc(sizeof(*cxl_nvd), GFP_KERNEL);
> + if (!cxl_nvd)
> + return ERR_PTR(-ENOMEM);
> +
> + dev = &cxl_nvd->dev;
> + cxl_nvd->cxlmd = cxlmd;
> + device_initialize(dev);
> + device_set_pm_not_required(dev);
> + dev->parent = &cxlmd->dev;
> + dev->bus = &cxl_bus_type;
> + dev->type = &cxl_nvdimm_type;
> +
> + return cxl_nvd;
> +}
> +
> +int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd)
> +{
> + struct cxl_nvdimm *cxl_nvd;
> + struct device *dev;
> + int rc;
> +
> + cxl_nvd = cxl_nvdimm_alloc(cxlmd);
> + if (IS_ERR(cxl_nvd))
> + return PTR_ERR(cxl_nvd);
> +
> + dev = &cxl_nvd->dev;
> + rc = dev_set_name(dev, "pmem%d", cxlmd->id);
> + if (rc)
> + goto err;
> +
> + rc = device_add(dev);
> + if (rc)
> + goto err;
> +
> + dev_dbg(host, "%s: register %s\n", dev_name(dev->parent),
> + dev_name(dev));
> +
> + return devm_add_action_or_reset(host, unregister_dev, dev);
> +
> +err:
> + put_device(dev);
> + return rc;
> +}
> +EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm);
> +
> /**
> * cxl_probe_device_regs() - Detect CXL Device register blocks
> * @dev: Host device of the @base mapping
> @@ -930,6 +1014,8 @@ static int cxl_device_id(struct device *dev)
> {
> if (dev->type == &cxl_nvdimm_bridge_type)
> return CXL_DEVICE_NVDIMM_BRIDGE;
> + if (dev->type == &cxl_nvdimm_type)
> + return CXL_DEVICE_NVDIMM;
> return 0;
> }
>
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 47fcb7ad5978..3f9a6f7b05db 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -213,6 +213,13 @@ struct cxl_nvdimm_bridge {
> enum cxl_nvdimm_brige_state state;
> };
>
> +struct cxl_mem;
Above looks unrelated as you've not added any uses of cxl_mem
> +struct cxl_nvdimm {
> + struct device dev;
> + struct cxl_memdev *cxlmd;
> + struct nvdimm *nvdimm;
> +};
> +
> /**
> * struct cxl_port - logical collection of upstream port devices and
> * downstream port devices to construct a CXL memory
> @@ -299,7 +306,8 @@ int __cxl_driver_register(struct cxl_driver *cxl_drv,
> struct module *owner,
> #define cxl_driver_register(x) __cxl_driver_register(x, THIS_MODULE,
> KBUILD_MODNAME)
> void cxl_driver_unregister(struct cxl_driver *cxl_drv);
>
> -#define CXL_DEVICE_NVDIMM_BRIDGE 1
> +#define CXL_DEVICE_NVDIMM_BRIDGE 1
> +#define CXL_DEVICE_NVDIMM 2
>
> #define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
> #define CXL_MODALIAS_FMT "cxl:t%d"
> @@ -307,4 +315,7 @@ void cxl_driver_unregister(struct cxl_driver *cxl_drv);
> struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev);
> struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
> struct cxl_port *port);
> +struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev);
> +bool is_cxl_nvdimm(struct device *dev);
> +int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd);
> #endif /* __CXL_H__ */
> diff --git a/drivers/cxl/mem.h b/drivers/cxl/mem.h
> index 13868ff7cadf..8f02d02b26b4 100644
> --- a/drivers/cxl/mem.h
> +++ b/drivers/cxl/mem.h
> @@ -2,6 +2,8 @@
> /* Copyright(c) 2020-2021 Intel Corporation. */
> #ifndef __CXL_MEM_H__
> #define __CXL_MEM_H__
> +#include <linux/cdev.h>
Unrelated to rest of patch. Good to add this, but not hidden in this
patch.
> +#include "cxl.h"
>
> /* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */
> #define CXLMDEV_STATUS_OFFSET 0x0
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 5a1705b52278..83e81b44c8f5 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -1313,7 +1313,8 @@ static struct cxl_memdev *cxl_memdev_alloc(struct
> cxl_mem *cxlm)
> return ERR_PTR(rc);
> }
>
> -static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
> +static struct cxl_memdev *devm_cxl_add_memdev(struct device *host,
> + struct cxl_mem *cxlm)
> {
> struct cxl_memdev *cxlmd;
> struct device *dev;
> @@ -1322,7 +1323,7 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
>
> cxlmd = cxl_memdev_alloc(cxlm);
> if (IS_ERR(cxlmd))
> - return PTR_ERR(cxlmd);
> + return cxlmd;
>
> dev = &cxlmd->dev;
> rc = dev_set_name(dev, "mem%d", cxlmd->id);
> @@ -1340,8 +1341,10 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
> if (rc)
> goto err;
>
> - return devm_add_action_or_reset(dev->parent, cxl_memdev_unregister,
> - cxlmd);
> + rc = devm_add_action_or_reset(host, cxl_memdev_unregister, cxlmd);
> + if (rc)
> + return ERR_PTR(rc);
> + return cxlmd;
>
> err:
> /*
> @@ -1350,7 +1353,7 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
> */
> cxl_memdev_shutdown(cxlmd);
> put_device(dev);
> - return rc;
> + return ERR_PTR(rc);
> }
>
> static int cxl_xfer_log(struct cxl_mem *cxlm, uuid_t *uuid, u32 size, u8
> *out)
> @@ -1561,6 +1564,7 @@ static int cxl_mem_identify(struct cxl_mem *cxlm)
>
> static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id
> *id)
> {
> + struct cxl_memdev *cxlmd;
> struct cxl_mem *cxlm;
> int rc;
>
> @@ -1588,7 +1592,14 @@ static int cxl_mem_probe(struct pci_dev *pdev, const
> struct pci_device_id *id)
> if (rc)
> return rc;
>
> - return cxl_mem_add_memdev(cxlm);
> + cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlm);
> + if (IS_ERR(cxlmd))
> + return PTR_ERR(cxlmd);
> +
> + if (range_len(&cxlm->pmem_range) && IS_ENABLED(CONFIG_CXL_PMEM))
> + rc = devm_cxl_add_nvdimm(&pdev->dev, cxlmd);
> +
> + return rc;
> }
>
> static const struct pci_device_id cxl_mem_pci_tbl[] = {
> diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
> index 0067bd734559..1ed19e213157 100644
> --- a/drivers/cxl/pmem.c
> +++ b/drivers/cxl/pmem.c
> @@ -3,7 +3,10 @@
> #include <linux/libnvdimm.h>
> #include <linux/device.h>
> #include <linux/module.h>
> +#include <linux/ndctl.h>
> +#include <linux/async.h>
> #include <linux/slab.h>
> +#include "mem.h"
> #include "cxl.h"
>
> /*
> @@ -13,6 +16,64 @@
> */
> static struct workqueue_struct *cxl_pmem_wq;
>
> +static void unregister_nvdimm(void *nvdimm)
> +{
> + nvdimm_delete(nvdimm);
> +}
> +
> +static int match_nvdimm_bridge(struct device *dev, const void *data)
> +{
> + return strcmp(dev_name(dev), "nvdimm-bridge") == 0;
> +}
> +
> +static struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(void)
> +{
> + struct device *dev;
> +
> + dev = bus_find_device(&cxl_bus_type, NULL, NULL, match_nvdimm_bridge);
Hmm. It's a singleton, so you could just stash the pointer somewhere
appropriate, but I guess this avoids adding extra infrastructure around
that, so fair enough.
> + if (!dev)
> + return NULL;
> + return to_cxl_nvdimm_bridge(dev);
> +}
> +
> +static int cxl_nvdimm_probe(struct device *dev)
> +{
> + struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
> + struct cxl_nvdimm_bridge *cxl_nvb;
> + unsigned long flags = 0;
> + struct nvdimm *nvdimm;
> + int rc = -ENXIO;
> +
> + cxl_nvb = cxl_find_nvdimm_bridge();
> + if (!cxl_nvb)
> + return -ENXIO;
> +
> + device_lock(&cxl_nvb->dev);
> + if (!cxl_nvb->nvdimm_bus)
> + goto out;
> +
> + set_bit(NDD_LABELING, &flags);
> + nvdimm = nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd, NULL, flags, 0, 0,
> + NULL);
> + if (!nvdimm)
> + goto out;
> +
> + dev_set_drvdata(dev, nvdimm);
Why? No harm done, but I wanted to check this was only used to get the
nvdimm, but can't find where it's used at all.
> +
> + rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm);
> +out:
> + device_unlock(&cxl_nvb->dev);
> + put_device(&cxl_nvb->dev);
> +
> + return rc;
> +}
> +
> +static struct cxl_driver cxl_nvdimm_driver = {
> + .name = "cxl_nvdimm",
> + .probe = cxl_nvdimm_probe,
> + .id = CXL_DEVICE_NVDIMM,
> +};
> +
> static int cxl_pmem_ctl(struct nvdimm_bus_descriptor *nd_desc,
> struct nvdimm *nvdimm, unsigned int cmd, void *buf,
> unsigned int buf_len, int *cmd_rc)
> @@ -28,19 +89,31 @@ static void online_nvdimm_bus(struct cxl_nvdimm_bridge
> *cxl_nvb)
> nvdimm_bus_register(&cxl_nvb->dev, &cxl_nvb->nd_desc);
> }
>
> -static void offline_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb)
> +static int cxl_nvdimm_release_driver(struct device *dev, void *data)
> {
> - if (!cxl_nvb->nvdimm_bus)
> - return;
> - nvdimm_bus_unregister(cxl_nvb->nvdimm_bus);
> - cxl_nvb->nvdimm_bus = NULL;
> + if (!is_cxl_nvdimm(dev))
> + return 0;
> + device_release_driver(dev);
> + return 0;
> +}
> +
> +static void offline_nvdimm_bus(struct nvdimm_bus *nvdimm_bus)
> +{
> + /*
> + * Set the state of cxl_nvdimm devices to unbound / idle before
> + * nvdimm_bus_unregister() rips the nvdimm objects out from
> + * underneath them.
> + */
> + bus_for_each_dev(&cxl_bus_type, NULL, NULL, cxl_nvdimm_release_driver);
> + nvdimm_bus_unregister(nvdimm_bus);
> }
>
> static void cxl_nvb_update_state(struct work_struct *work)
> {
> struct cxl_nvdimm_bridge *cxl_nvb =
> container_of(work, typeof(*cxl_nvb), state_work);
> - bool release = false;
> + struct nvdimm_bus *nvdimm_bus = NULL;
> + bool release = false, rescan = false;
>
> device_lock(&cxl_nvb->dev);
> switch (cxl_nvb->state) {
> @@ -50,11 +123,13 @@ static void cxl_nvb_update_state(struct work_struct
> *work)
> dev_err(&cxl_nvb->dev,
> "failed to establish nvdimm bus\n");
> release = true;
> - }
> + } else
> + rescan = true;
> break;
> case CXL_NVB_OFFLINE:
> case CXL_NVB_DEAD:
> - offline_nvdimm_bus(cxl_nvb);
> + nvdimm_bus = cxl_nvb->nvdimm_bus;
Perhaps rename this to make it clear that it only exists as a means
to offline it later? I wondered briefly why you were offlining
any bus that existed (e.g. in the online case)
nvdimm_bus_to_offline = ...
> + cxl_nvb->nvdimm_bus = NULL;
> break;
> default:
> break;
> @@ -63,6 +138,13 @@ static void cxl_nvb_update_state(struct work_struct *work)
>
> if (release)
> device_release_driver(&cxl_nvb->dev);
> + if (rescan) {
> + int rc = bus_rescan_devices(&cxl_bus_type);
> +
> + dev_dbg(&cxl_nvb->dev, "rescan: %d\n", rc);
> + }
> + if (nvdimm_bus)
> + offline_nvdimm_bus(nvdimm_bus);
>
> put_device(&cxl_nvb->dev);
> }
> @@ -113,23 +195,29 @@ static __init int cxl_pmem_init(void)
> int rc;
>
> cxl_pmem_wq = alloc_ordered_workqueue("cxl_pmem", 0);
> -
Shouldn't be here obviously. Move to earlier patch.
> if (!cxl_pmem_wq)
> return -ENXIO;
>
> rc = cxl_driver_register(&cxl_nvdimm_bridge_driver);
> if (rc)
> - goto err;
> + goto err_bridge;
> +
> + rc = cxl_driver_register(&cxl_nvdimm_driver);
> + if (rc)
> + goto err_nvdimm;
>
> return 0;
>
> -err:
> +err_nvdimm:
> + cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
> +err_bridge:
> destroy_workqueue(cxl_pmem_wq);
> return rc;
> }
>
> static __exit void cxl_pmem_exit(void)
> {
> + cxl_driver_unregister(&cxl_nvdimm_driver);
> cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
> destroy_workqueue(cxl_pmem_wq);
> }
> @@ -139,3 +227,4 @@ module_init(cxl_pmem_init);
> module_exit(cxl_pmem_exit);
> MODULE_IMPORT_NS(CXL);
> MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM_BRIDGE);
> +MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM);
>
