commit 08b9e0ab8a upstream.
There is a potential race between queue_work() returning and the
queued-work running that could result in put_device() running before
get_device(). Introduce the cxl_nvdimm_bridge_state_work() helper that
takes the reference unconditionally, but drops it if no new work was
queued, to keep the references balanced.
Fixes: 8fdcb1704f ("cxl/pmem: Add initial infrastructure for pmem support")
Cc: <stable@vger.kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/163553734757.2509761.3305231863616785470.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CXL core is growing, and it's already arguably unmanageable. To support
future growth, move core functionality to a new directory and rename the
file to represent just bus support. Future work will remove non-bus
functionality.
Note that mem.h is renamed to cxlmem.h to avoid a namespace collision
with the global ARCH=um mem.h header.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/162792537866.368511.8915631504621088321.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/162380012696.3039556.4293801691038740850.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Register an 'nvdimm-bridge' device to act as an anchor for a libnvdimm
bus hierarchy. Also, flesh out the cxl_bus definition to allow a
cxl_nvdimm_bridge_driver to attach to the bridge and trigger the
nvdimm-bus registration.
The creation of the bridge is gated on the detection of a PMEM capable
address space registered to the root. The bridge indirection allows the
libnvdimm module to remain unloaded on platforms without PMEM support.
Given that the probing of ACPI0017 is asynchronous to CXL endpoint
devices, and the expectation that CXL endpoint devices register other
PMEM resources on the 'CXL' nvdimm bus, a workqueue is added. The
workqueue is needed to run bus_rescan_devices() outside of the
device_lock() of the nvdimm-bridge device to rendezvous nvdimm resources
as they arrive. For now only the bus is taken online/offline in the
workqueue.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/162379909706.2993820.14051258608641140169.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Dan Williams
Ben Widawsky