powerpc/pseries: Check memory device state before onlining/offlining
When DLPAR adding or removing memory we need to check the device offline status before trying to online/offline the memory. This is needed because calls to device_online() and device_offline() will return non-zero for memory that is already online and offline respectively. This update resolves two scenarios. First, for a kernel built with auto-online memory enabled (CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y), memory will be onlined as part of calls to add_memory(). After adding the memory the pseries DLPAR code tries to online it and fails since the memory is already online. The DLPAR code then tries to remove the memory which produces the oops message below because the memory is not offline. The second scenario occurs when removing memory that is already offline, i.e. marking memory offline (via sysfs) and then trying to remove that memory. This doesn't work because offlining the already offline memory does not succeed and the DLPAR code then fails the DLPAR remove operation. The fix for both scenarios is to check the device.offline status before making the calls to device_online() or device_offline(). kernel BUG at mm/memory_hotplug.c:1936! ... NIP [c0000000002ca428] .remove_memory+0xb8/0xc0 LR [c0000000002ca3cc] .remove_memory+0x5c/0xc0 Call Trace: .remove_memory+0x5c/0xc0 (unreliable) .dlpar_add_lmb+0x384/0x400 .dlpar_memory+0x5dc/0xca0 .handle_dlpar_errorlog+0x74/0xe0 .pseries_hp_work_fn+0x2c/0x90 .process_one_work+0x17c/0x460 .worker_thread+0x88/0x500 .kthread+0x15c/0x1a0 .ret_from_kernel_thread+0x58/0xc0 Fixes: 943db62c ("powerpc/pseries: Revert 'Auto-online hotplugged memory'") Signed-off-by:Nathan Fontenot <nfont@linux.vnet.ibm.com> [mpe: Use bool, add explicit rc=0 case, change log typos & formatting] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
parent
8a583c0a
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