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f8dc1bde18
dax_hmem (ab)uses a platform device to allow for a module to autoload in the presence of "Soft Reserved" resources. The dax_hmem driver had no dependencies on the "hmem_platform" device being a singleton until the recent "dax_hmem vs dax_cxl" takeover solution. Replace the layering violation of dax_hmem_work assuming that there will never be more than one "hmem_platform" device associated with a global work item with a dax_hmem local workqueue that can theoretically support any number of hmem_platform devices. Fixup the reference counting to only pin the device while it is live in the queue. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://patch.msgid.link/20260327052821.440749-7-dan.j.williams@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
104 lines
2.2 KiB
C
104 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/platform_device.h>
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#include <linux/memregion.h>
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#include <linux/module.h>
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#include <linux/dax.h>
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#include <linux/mm.h>
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#include "../bus.h"
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static bool nohmem;
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module_param_named(disable, nohmem, bool, 0444);
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static bool platform_initialized;
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static DEFINE_MUTEX(hmem_resource_lock);
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static struct resource hmem_active = {
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.name = "HMEM devices",
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.start = 0,
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.end = -1,
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.flags = IORESOURCE_MEM,
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};
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int walk_hmem_resources(struct device *host, walk_hmem_fn fn)
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{
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struct resource *res;
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int rc = 0;
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mutex_lock(&hmem_resource_lock);
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for (res = hmem_active.child; res; res = res->sibling) {
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rc = fn(host, (int) res->desc, res);
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if (rc)
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break;
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}
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mutex_unlock(&hmem_resource_lock);
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return rc;
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}
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EXPORT_SYMBOL_GPL(walk_hmem_resources);
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static void hmem_work(struct work_struct *work)
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{
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/* place holder until dax_hmem driver attaches */
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}
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static struct hmem_platform_device hmem_platform = {
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.pdev = {
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.name = "hmem_platform",
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.id = 0,
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},
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.work = __WORK_INITIALIZER(hmem_platform.work, hmem_work),
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};
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static void __hmem_register_resource(int target_nid, struct resource *res)
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{
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struct resource *new;
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int rc;
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new = __request_region(&hmem_active, res->start, resource_size(res), "",
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0);
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if (!new) {
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pr_debug("hmem range %pr already active\n", res);
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return;
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}
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new->desc = target_nid;
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if (platform_initialized)
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return;
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rc = platform_device_register(&hmem_platform.pdev);
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if (rc) {
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pr_err_once("failed to register device-dax hmem_platform device\n");
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return;
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}
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platform_initialized = true;
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}
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void hmem_register_resource(int target_nid, struct resource *res)
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{
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if (nohmem)
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return;
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mutex_lock(&hmem_resource_lock);
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__hmem_register_resource(target_nid, res);
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mutex_unlock(&hmem_resource_lock);
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}
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static __init int hmem_register_one(struct resource *res, void *data)
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{
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hmem_register_resource(phys_to_target_node(res->start), res);
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return 0;
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}
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static __init int hmem_init(void)
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{
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walk_soft_reserve_res(0, -1, NULL, hmem_register_one);
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return 0;
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}
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/*
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* As this is a fallback for address ranges unclaimed by the ACPI HMAT
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* parsing it must be at an initcall level greater than hmat_init().
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*/
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device_initcall(hmem_init);
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