kernel/linux.git/drivers/cxl/core/memdev.c, branch linux-7.0.y

cxl/memdev: fix deadlock in cxl_memdev_autoremove() on attach failure

2026-02-23T16:03:44+00:00

cxl_memdev_autoremove() takes device_lock(&cxlmd->dev) via guard(device) and then calls cxl_memdev_unregister() when the attach callback was provided but cxl_mem_probe() failed to bind. cxl_memdev_unregister() calls cdev_device_del() device_del() bus_remove_device() device_release_driver() This path is reached when a driver uses the @attach parameter to devm_cxl_add_memdev() and the CXL topology fails to enumerate (e.g. DVSEC range registers decode outside platform-defined CXL ranges, causing the endpoint port probe to fail). Add cxl_memdev_attach_failed() to set the scope of the check correctly. Reported-by: kreview-c94b85d6d2 Fixes: 29317f8dc6ed ("cxl/mem: Introduce cxl_memdev_attach for CXL-dependent operation") Signed-off-by: Gregory Price Reviewed-by: Dan Williams Reviewed-by: Davidlohr Bueso Link: https://patch.msgid.link/20260211192228.2148713-1-gourry@gourry.net Signed-off-by: Dave Jiang

Convert 'alloc_flex' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This is the exact same thing as the 'alloc_obj()' version, only much smaller because there are a lot fewer users of the *alloc_flex() interface. As with alloc_obj() version, this was done entirely with mindless brute force, using the same script, except using 'flex' in the pattern rather than 'objs*'. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

cxl/mem: Introduce cxl_memdev_attach for CXL-dependent operation

2026-01-05T17:58:04+00:00

Unlike the cxl_pci class driver that opportunistically enables memory expansion with no other dependent functionality, CXL accelerator drivers have distinct PCIe-only and CXL-enhanced operation states. If CXL is available some additional coherent memory/cache operations can be enabled, otherwise traditional DMA+MMIO over PCIe/CXL.io is a fallback. This constitutes a new mode of operation where the caller of devm_cxl_add_memdev() wants to make a "go/no-go" decision about running in CXL accelerated mode or falling back to PCIe-only operation. Part of that decision making process likely also includes additional CXL-acceleration-specific resource setup. Encapsulate both of those requirements into 'struct cxl_memdev_attach' that provides a ->probe() callback. The probe callback runs in cxl_mem_probe() context, after the port topology is successfully attached for the given memdev. It supports a contract where, upon successful return from devm_cxl_add_memdev(), everything needed for CXL accelerated operation has been enabled. Additionally the presence of @cxlmd->attach indicates that the accelerator driver be detached when CXL operation ends. This conceptually makes a CXL link loss event mirror a PCIe link loss event which results in triggering the ->remove() callback of affected devices+drivers. A driver can re-attach to recover back to PCIe-only operation. Live recovery, i.e. without a ->remove()/->probe() cycle, is left as a future consideration. [ dj: Repalce with updated commit log from Dan ] Cc: Smita Koralahalli Reviewed-by: Ben Cheatham Reviewed-by: Dave Jiang Tested-by: Alejandro Lucero Reviewed-by: Jonathan Cameron Link: https://patch.msgid.link/20251216005616.3090129-7-dan.j.williams@intel.com Signed-off-by: Dan Williams Signed-off-by: Dave Jiang

cxl/mem: Drop @host argument to devm_cxl_add_memdev()

2026-01-05T17:14:53+00:00

In all cases the device that created the 'struct cxl_dev_state' instance is also the device to host the devm cleanup of devm_cxl_add_memdev(). This simplifies the function prototype, and limits a degree of freedom of the API. Cc: Smita Koralahalli Reviewed-by: Jonathan Cameron Reviewed-by: Alison Schofield Reviewed-by: Dave Jiang Reviewed-by: Ben Cheatham Tested-by: Alejandro Lucero Link: https://patch.msgid.link/20251216005616.3090129-6-dan.j.williams@intel.com Signed-off-by: Dan Williams Signed-off-by: Dave Jiang

cxl/mem: Convert devm_cxl_add_memdev() to scope-based-cleanup

2026-01-05T17:14:36+00:00

In preparation for adding more setup steps, convert the current implementation to scope-based cleanup. The cxl_memdev_shutdown() is only required after cdev_device_add(). With that moved to a helper function it precludes the need to add scope-based-handler for that cleanup if devm_add_action_or_reset() fails. Cc: Smita Koralahalli Reviewed-by: Alison Schofield Reviewed-by: Dave Jiang Reviewed-by: Ben Cheatham Tested-by: Alejandro Lucero Reviewed-by: Jonathan Cameron Link: https://patch.msgid.link/20251216005616.3090129-5-dan.j.williams@intel.com Signed-off-by: Dan Williams Signed-off-by: Dave Jiang

cxl/mem: Arrange for always-synchronous memdev attach

2026-01-05T17:13:53+00:00

In preparation for CXL accelerator drivers that have a hard dependency on CXL capability initialization, arrange for cxl_mem_probe() to always run synchronous with the device_add() of cxl_memdev instances. I.e. cxl_mem_driver registration is always complete before the first memdev creation event. At present, cxl_pci does not care about the attach state of the cxl_memdev because all generic memory expansion functionality can be handled by the cxl_core. For accelerators, however, that driver needs to perform driver specific initialization if CXL is available, or execute a fallback to PCIe only operation. This synchronous attach guarantee is also needed for Soft Reserve Recovery, which is an effort that needs to assert that devices have had a chance to attach before making a go / no-go decision on proceeding with CXL subsystem initialization. By moving devm_cxl_add_memdev() to cxl_mem.ko it removes async module loading as one reason that a memdev may not be attached upon return from devm_cxl_add_memdev(). Cc: Smita Koralahalli Cc: Alejandro Lucero Reviewed-by: Jonathan Cameron Tested-by: Alison Schofield Reviewed-by: Alison Schofield Reviewed-by: Ben Cheatham Reviewed-by: Dave Jiang Tested-by: Alejandro Lucero Link: https://patch.msgid.link/20251216005616.3090129-3-dan.j.williams@intel.com Signed-off-by: Dan Williams Signed-off-by: Dave Jiang

cxl/mem: Fix devm_cxl_memdev_edac_release() confusion

2026-01-05T17:13:33+00:00

A device release method is only for undoing allocations on the path to preparing the device for device_add(). In contrast, devm allocations are post device_add(), are acquired during / after ->probe() and are released synchronous with ->remove(). So, a "devm" helper in a "release" method is a clear anti-pattern. Move this devm release action where it belongs, an action created at edac object creation time. Otherwise, this leaks resources until cxl_memdev_release() time which may be long after these xarray and error record caches have gone idle. Note, this also fixes up the type of @cxlmd->err_rec_array which needlessly dropped type-safety. Fixes: 0b5ccb0de1e2 ("cxl/edac: Support for finding memory operation attributes from the current boot") Cc: Dave Jiang Cc: Jonathan Cameron Cc: Shiju Jose Cc: Alison Schofield Reviewed-by: Alison Schofield Reviewed-by: Ben Cheatham Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Tested-by: Shiju Jose Reviewed-by: Shiju Jose Tested-by: Alejandro Lucero Link: https://patch.msgid.link/20251216005616.3090129-2-dan.j.williams@intel.com Signed-off-by: Dan Williams Signed-off-by: Dave Jiang

cxl/region: Add inject and clear poison by region offset

2025-08-12T23:02:00+00:00

Add CXL region debugfs attributes to inject and clear poison based on an offset into the region. These new interfaces allow users to operate on poison at the region level without needing to resolve Device Physical Addresses (DPA) or target individual memdevs. The implementation uses a new helper, region_offset_to_dpa_result() that applies decoder interleave logic, including XOR-based address decoding when applicable. Note that XOR decodes rely on driver internal xormaps which are not exposed to userspace. So, this support is not only a simplification of poison operations that could be done using existing per memdev operations, but also it enables this functionality for XOR interleaved regions for the first time. New debugfs attributes are added in /sys/kernel/debug/cxl/regionX/: inject_poison and clear_poison. These are only exposed if all memdevs participating in the region support both inject and clear commands, ensuring consistent and reliable behavior across multi-device regions. If tracing is enabled, these operations are logged as cxl_poison events in /sys/kernel/tracing/trace. The ABI documentation warns users of the significant risks that come with using these capabilities. A CXL Maturity Map update shows this user flow is now supported. Signed-off-by: Alison Schofield Reviewed-by: Jonathan Cameron Link: https://patch.msgid.link/f3fd8628ab57ea79704fb2d645902cd499c066af.1754290144.git.alison.schofield@intel.com Signed-off-by: Dave Jiang