From: Dan Williams Date: Sun, 22 Mar 2026 19:53:38 +0000 (+0000) Subject: dax/cxl, hmem: Initialize hmem early and defer dax_cxl binding X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=39aa1d4be12bf9f685adaa06aa2d997c1c611b16;p=thirdparty%2Fkernel%2Flinux.git dax/cxl, hmem: Initialize hmem early and defer dax_cxl binding Move hmem/ earlier in the dax Makefile so that hmem_init() runs before dax_cxl. In addition, defer registration of the dax_cxl driver to a workqueue instead of using module_cxl_driver(). This ensures that dax_hmem has an opportunity to initialize and register its deferred callback and make ownership decisions before dax_cxl begins probing and claiming Soft Reserved ranges. Mark the dax_cxl driver as PROBE_PREFER_ASYNCHRONOUS so its probe runs out of line from other synchronous probing avoiding ordering dependencies while coordinating ownership decisions with dax_hmem. Signed-off-by: Smita Koralahalli Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Tested-by: Tomasz Wolski Link: https://patch.msgid.link/20260322195343.206900-6-Smita.KoralahalliChannabasappa@amd.com Signed-off-by: Dan Williams Signed-off-by: Dave Jiang --- diff --git a/drivers/dax/Makefile b/drivers/dax/Makefile index 5ed5c39857c8b..70e996bf15261 100644 --- a/drivers/dax/Makefile +++ b/drivers/dax/Makefile @@ -1,4 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 +obj-y += hmem/ obj-$(CONFIG_DAX) += dax.o obj-$(CONFIG_DEV_DAX) += device_dax.o obj-$(CONFIG_DEV_DAX_KMEM) += kmem.o @@ -10,5 +11,3 @@ dax-y += bus.o device_dax-y := device.o dax_pmem-y := pmem.o dax_cxl-y := cxl.o - -obj-y += hmem/ diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c index 13cd94d32ff7a..a2136adfa186e 100644 --- a/drivers/dax/cxl.c +++ b/drivers/dax/cxl.c @@ -38,10 +38,35 @@ static struct cxl_driver cxl_dax_region_driver = { .id = CXL_DEVICE_DAX_REGION, .drv = { .suppress_bind_attrs = true, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, }; -module_cxl_driver(cxl_dax_region_driver); +static void cxl_dax_region_driver_register(struct work_struct *work) +{ + cxl_driver_register(&cxl_dax_region_driver); +} + +static DECLARE_WORK(cxl_dax_region_driver_work, cxl_dax_region_driver_register); + +static int __init cxl_dax_region_init(void) +{ + /* + * Need to resolve a race with dax_hmem wanting to drive regions + * instead of CXL + */ + queue_work(system_long_wq, &cxl_dax_region_driver_work); + return 0; +} +module_init(cxl_dax_region_init); + +static void __exit cxl_dax_region_exit(void) +{ + flush_work(&cxl_dax_region_driver_work); + cxl_driver_unregister(&cxl_dax_region_driver); +} +module_exit(cxl_dax_region_exit); + MODULE_ALIAS_CXL(CXL_DEVICE_DAX_REGION); MODULE_DESCRIPTION("CXL DAX: direct access to CXL regions"); MODULE_LICENSE("GPL");