Refactor kmem _probe() _remove() by extracting init, cleanup, hotplug, and hot-remove logic into separate helper functions:
- dax_kmem_init_resources: inits IO_RESOURCE w/ request_mem_region - dax_kmem_cleanup_resources: cleans up initialized IO_RESOURCE - dax_kmem_do_hotplug: handles memory region reservation and adding - dax_kmem_do_hotremove: handles memory removal and resource cleanup This is a pure refactoring with no functional change. The helpers will enable future extensions to support more granular control over memory hotplug operations. We need to split hotplug/remove and init/cleanup in order to have the resources available for hot-add. Otherwise, when probe occurs, the dax devices are never added to sysfs because the resources are never registered. Signed-off-by: Gregory Price <[email protected]> --- drivers/dax/kmem.c | 300 +++++++++++++++++++++++++++++++-------------- 1 file changed, 206 insertions(+), 94 deletions(-) diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index bb13d9ced2e9..3929cb8576de 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -65,14 +65,185 @@ static void kmem_put_memory_types(void) mt_put_memory_types(&kmem_memory_types); } +/** + * dax_kmem_do_hotplug - hotplug memory for dax kmem device + * @dev_dax: the dev_dax instance + * @data: the dax_kmem_data structure with resource tracking + * + * Hotplugs all ranges in the dev_dax region as system memory. + * + * Returns the number of successfully mapped ranges, or negative error. + */ +static int dax_kmem_do_hotplug(struct dev_dax *dev_dax, + struct dax_kmem_data *data, + int online_type) +{ + struct device *dev = &dev_dax->dev; + int i, rc, onlined = 0; + mhp_t mhp_flags; + + for (i = 0; i < dev_dax->nr_range; i++) { + struct range range; + + rc = dax_kmem_range(dev_dax, i, &range); + if (rc) + continue; + + mhp_flags = MHP_NID_IS_MGID; + if (dev_dax->memmap_on_memory) + mhp_flags |= MHP_MEMMAP_ON_MEMORY; + + /* + * Ensure that future kexec'd kernels will not treat + * this as RAM automatically. + */ + rc = add_memory_driver_managed(data->mgid, range.start, + range_len(&range), kmem_name, mhp_flags, + online_type); + + if (rc) { + dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n", + i, range.start, range.end); + if (onlined) + continue; + return rc; + } + onlined++; + } + + return onlined; +} + +/** + * dax_kmem_init_resources - create memory regions for dax kmem + * @dev_dax: the dev_dax instance + * @data: the dax_kmem_data structure with resource tracking + * + * Initializes all the resources for the DAX + * + * Returns the number of successfully mapped ranges, or negative error. + */ +static int dax_kmem_init_resources(struct dev_dax *dev_dax, + struct dax_kmem_data *data) +{ + struct device *dev = &dev_dax->dev; + int i, rc, mapped = 0; + + for (i = 0; i < dev_dax->nr_range; i++) { + struct resource *res; + struct range range; + + rc = dax_kmem_range(dev_dax, i, &range); + if (rc) + continue; + + /* Skip ranges already added */ + if (data->res[i]) + continue; + + /* Region is permanently reserved if hotremove fails. */ + res = request_mem_region(range.start, range_len(&range), + data->res_name); + if (!res) { + dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve region\n", + i, range.start, range.end); + /* + * Once some memory has been onlined we can't + * assume that it can be un-onlined safely. + */ + if (mapped) + continue; + return -EBUSY; + } + data->res[i] = res; + /* + * Set flags appropriate for System RAM. Leave ..._BUSY clear + * so that add_memory() can add a child resource. Do not + * inherit flags from the parent since it may set new flags + * unknown to us that will break add_memory() below. + */ + res->flags = IORESOURCE_SYSTEM_RAM; + mapped++; + } + return mapped; +} + +#ifdef CONFIG_MEMORY_HOTREMOVE +/** + * dax_kmem_do_hotremove - hot-remove memory for dax kmem device + * @dev_dax: the dev_dax instance + * @data: the dax_kmem_data structure with resource tracking + * + * Removes all ranges in the dev_dax region. + * + * Returns the number of successfully removed ranges. + */ +static int dax_kmem_do_hotremove(struct dev_dax *dev_dax, + struct dax_kmem_data *data) +{ + struct device *dev = &dev_dax->dev; + int i, success = 0; + + for (i = 0; i < dev_dax->nr_range; i++) { + struct range range; + int rc; + + rc = dax_kmem_range(dev_dax, i, &range); + if (rc) + continue; + + /* Skip ranges not currently added */ + if (!data->res[i]) + continue; + + rc = remove_memory(range.start, range_len(&range)); + if (rc == 0) { + success++; + continue; + } + any_hotremove_failed = true; + dev_err(dev, "mapping%d: %#llx-%#llx hotremove failed\n", + i, range.start, range.end); + } + + return success; +} +#else +static int dax_kmem_do_hotremove(struct dev_dax *dev_dax, + struct dax_kmem_data *data) +{ + return -ENOSUPP; +} +#endif /* CONFIG_MEMORY_HOTREMOVE */ + +/** + * dax_kmem_cleanup_resources - remove the dax memory resources + * @dev_dax: the dev_dax instance + * @data: the dax_kmem_data structure with resource tracking + * + * Removes all resources in the dev_dax region. + */ +static void dax_kmem_cleanup_resources(struct dev_dax *dev_dax, + struct dax_kmem_data *data) +{ + int i; + + for (i = 0; i < dev_dax->nr_range; i++) { + if (!data->res[i]) + continue; + remove_resource(data->res[i]); + kfree(data->res[i]); + data->res[i] = NULL; + } +} + static int dev_dax_kmem_probe(struct dev_dax *dev_dax) { struct device *dev = &dev_dax->dev; unsigned long total_len = 0, orig_len = 0; struct dax_kmem_data *data; struct memory_dev_type *mtype; - int i, rc, mapped = 0; - mhp_t mhp_flags; + int i, rc; int numa_node; int adist = MEMTIER_DEFAULT_DAX_ADISTANCE; @@ -134,68 +305,26 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) goto err_reg_mgid; data->mgid = rc; - for (i = 0; i < dev_dax->nr_range; i++) { - struct resource *res; - struct range range; - - rc = dax_kmem_range(dev_dax, i, &range); - if (rc) - continue; - - /* Region is permanently reserved if hotremove fails. */ - res = request_mem_region(range.start, range_len(&range), data->res_name); - if (!res) { - dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve region\n", - i, range.start, range.end); - /* - * Once some memory has been onlined we can't - * assume that it can be un-onlined safely. - */ - if (mapped) - continue; - rc = -EBUSY; - goto err_request_mem; - } - data->res[i] = res; - - /* - * Set flags appropriate for System RAM. Leave ..._BUSY clear - * so that add_memory() can add a child resource. Do not - * inherit flags from the parent since it may set new flags - * unknown to us that will break add_memory() below. - */ - res->flags = IORESOURCE_SYSTEM_RAM; - - mhp_flags = MHP_NID_IS_MGID; - if (dev_dax->memmap_on_memory) - mhp_flags |= MHP_MEMMAP_ON_MEMORY; - - /* - * Ensure that future kexec'd kernels will not treat - * this as RAM automatically. - */ - rc = add_memory_driver_managed(data->mgid, range.start, - range_len(&range), kmem_name, mhp_flags, - mhp_get_default_online_type()); + dev_set_drvdata(dev, data); - if (rc) { - dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n", - i, range.start, range.end); - remove_resource(res); - kfree(res); - data->res[i] = NULL; - if (mapped) - continue; - goto err_request_mem; - } - mapped++; - } + rc = dax_kmem_init_resources(dev_dax, data); + if (rc < 0) + goto err_resources; - dev_set_drvdata(dev, data); + /* + * Hotplug using the system default policy - this preserves backwards + * for existing users who rely on the default auto-online behavior. + */ + rc = dax_kmem_do_hotplug(dev_dax, data, mhp_get_default_online_type()); + if (rc < 0) + goto err_hotplug; return 0; -err_request_mem: +err_hotplug: + dax_kmem_cleanup_resources(dev_dax, data); +err_resources: + dev_set_drvdata(dev, NULL); memory_group_unregister(data->mgid); err_reg_mgid: kfree(data->res_name); @@ -209,7 +338,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) #ifdef CONFIG_MEMORY_HOTREMOVE static void dev_dax_kmem_remove(struct dev_dax *dev_dax) { - int i, success = 0; + int success; int node = dev_dax->target_node; struct device *dev = &dev_dax->dev; struct dax_kmem_data *data = dev_get_drvdata(dev); @@ -220,42 +349,25 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax) * there is no way to hotremove this memory until reboot because device * unbind will succeed even if we return failure. */ - for (i = 0; i < dev_dax->nr_range; i++) { - struct range range; - int rc; - - rc = dax_kmem_range(dev_dax, i, &range); - if (rc) - continue; - - rc = remove_memory(range.start, range_len(&range)); - if (rc == 0) { - remove_resource(data->res[i]); - kfree(data->res[i]); - data->res[i] = NULL; - success++; - continue; - } - any_hotremove_failed = true; - dev_err(dev, - "mapping%d: %#llx-%#llx cannot be hotremoved until the next reboot\n", - i, range.start, range.end); + success = dax_kmem_do_hotremove(dev_dax, data); + if (success < dev_dax->nr_range) { + dev_err(dev, "Hotplug regions stuck online until reboot\n"); + return; } - if (success >= dev_dax->nr_range) { - memory_group_unregister(data->mgid); - kfree(data->res_name); - kfree(data); - dev_set_drvdata(dev, NULL); - /* - * Clear the memtype association on successful unplug. - * If not, we have memory blocks left which can be - * offlined/onlined later. We need to keep memory_dev_type - * for that. This implies this reference will be around - * till next reboot. - */ - clear_node_memory_type(node, NULL); - } + dax_kmem_cleanup_resources(dev_dax, data); + memory_group_unregister(data->mgid); + kfree(data->res_name); + kfree(data); + dev_set_drvdata(dev, NULL); + /* + * Clear the memtype association on successful unplug. + * If not, we have memory blocks left which can be + * offlined/onlined later. We need to keep memory_dev_type + * for that. This implies this reference will be around + * till next reboot. + */ + clear_node_memory_type(node, NULL); } #else static void dev_dax_kmem_remove(struct dev_dax *dev_dax) -- 2.52.0
