The mutex linear_mapping_mutex is defined at the of the file while its only two user are within the CONFIG_MEMORY_HOTPLUG block. A compile without CONFIG_MEMORY_HOTPLUG set fails on PREEMPT_RT because its mutex implementation is smart enough to realize that it is unused.
Move the definition of linear_mapping_mutex to ifdef block where it is used. Fixes: 1f73ad3e8d755 ("powerpc/mm: print warning in arch_remove_linear_mapping()") Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de> --- arch/powerpc/mm/mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index afab328d08874..d6c3f0b79f1d1 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -54,7 +54,6 @@ #include <mm/mmu_decl.h> -static DEFINE_MUTEX(linear_mapping_mutex); unsigned long long memory_limit; bool init_mem_is_free; @@ -72,6 +71,7 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, EXPORT_SYMBOL(phys_mem_access_prot); #ifdef CONFIG_MEMORY_HOTPLUG +static DEFINE_MUTEX(linear_mapping_mutex); #ifdef CONFIG_NUMA int memory_add_physaddr_to_nid(u64 start) -- 2.30.0