diff options
| -rw-r--r-- | arch/powerpc/platforms/pseries/msi.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c index b3ac2455faad..637300330507 100644 --- a/arch/powerpc/platforms/pseries/msi.c +++ b/arch/powerpc/platforms/pseries/msi.c @@ -4,6 +4,7 @@ * Copyright 2006-2007 Michael Ellerman, IBM Corp. */ +#include <linux/crash_dump.h> #include <linux/device.h> #include <linux/irq.h> #include <linux/msi.h> @@ -458,8 +459,28 @@ again: return hwirq; } - virq = irq_create_mapping_affinity(NULL, hwirq, - entry->affinity); + /* + * Depending on the number of online CPUs in the original + * kernel, it is likely for CPU #0 to be offline in a kdump + * kernel. The associated IRQs in the affinity mappings + * provided by irq_create_affinity_masks() are thus not + * started by irq_startup(), as per-design for managed IRQs. + * This can be a problem with multi-queue block devices driven + * by blk-mq : such a non-started IRQ is very likely paired + * with the single queue enforced by blk-mq during kdump (see + * blk_mq_alloc_tag_set()). This causes the device to remain + * silent and likely hangs the guest at some point. + * + * We don't really care for fine-grained affinity when doing + * kdump actually : simply ignore the pre-computed affinity + * masks in this case and let the default mask with all CPUs + * be used when creating the IRQ mappings. + */ + if (is_kdump_kernel()) + virq = irq_create_mapping(NULL, hwirq); + else + virq = irq_create_mapping_affinity(NULL, hwirq, + entry->affinity); if (!virq) { pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq); |