From: Nathan Fontenot Date: Wed, 2 Aug 2017 18:03:22 +0000 (-0400) Subject: powerpc/pseries: Check memory device state before onlining/offlining X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1a367063ca0c1c6f6f54b5abd7b4836b0866a07b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git 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: 943db62c316c ("powerpc/pseries: Revert 'Auto-online hotplugged memory'") Signed-off-by: Nathan Fontenot [mpe: Use bool, add explicit rc=0 case, change log typos & formatting] Signed-off-by: Michael Ellerman --- diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c index ca9b2f4aaa22..9e3afd238d34 100644 --- a/arch/powerpc/platforms/pseries/hotplug-memory.c +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c @@ -336,7 +336,38 @@ static struct memory_block *lmb_to_memblock(struct of_drconf_cell *lmb) return mem_block; } +static int dlpar_change_lmb_state(struct of_drconf_cell *lmb, bool online) +{ + struct memory_block *mem_block; + int rc; + + mem_block = lmb_to_memblock(lmb); + if (!mem_block) + return -EINVAL; + + if (online && mem_block->dev.offline) + rc = device_online(&mem_block->dev); + else if (!online && !mem_block->dev.offline) + rc = device_offline(&mem_block->dev); + else + rc = 0; + + put_device(&mem_block->dev); + + return rc; +} + +static int dlpar_online_lmb(struct of_drconf_cell *lmb) +{ + return dlpar_change_lmb_state(lmb, true); +} + #ifdef CONFIG_MEMORY_HOTREMOVE +static int dlpar_offline_lmb(struct of_drconf_cell *lmb) +{ + return dlpar_change_lmb_state(lmb, false); +} + static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size) { unsigned long block_sz, start_pfn; @@ -431,19 +462,13 @@ static int dlpar_add_lmb(struct of_drconf_cell *); static int dlpar_remove_lmb(struct of_drconf_cell *lmb) { - struct memory_block *mem_block; unsigned long block_sz; int nid, rc; if (!lmb_is_removable(lmb)) return -EINVAL; - mem_block = lmb_to_memblock(lmb); - if (!mem_block) - return -EINVAL; - - rc = device_offline(&mem_block->dev); - put_device(&mem_block->dev); + rc = dlpar_offline_lmb(lmb); if (rc) return rc; @@ -737,20 +762,6 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index, } #endif /* CONFIG_MEMORY_HOTREMOVE */ -static int dlpar_online_lmb(struct of_drconf_cell *lmb) -{ - struct memory_block *mem_block; - int rc; - - mem_block = lmb_to_memblock(lmb); - if (!mem_block) - return -EINVAL; - - rc = device_online(&mem_block->dev); - put_device(&mem_block->dev); - return rc; -} - static int dlpar_add_lmb(struct of_drconf_cell *lmb) { unsigned long block_sz;