Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption to prevent CPUs from going offline
from under us.
Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going
offline, while invoking from atomic context.
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Cc: sparclinux@xxxxxxxxxxxxxxx
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
---
arch/sparc/kernel/smp_64.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 77539ed..4f71a95 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -792,7 +792,9 @@ static void smp_cross_call_masked(unsigned long *func, u32 ctx, u64 data1, u64 d
/* Send cross call to all processors except self. */
static void smp_cross_call(unsigned long *func, u32 ctx, u64 data1, u64 data2)
{
+ get_online_cpus_atomic();
smp_cross_call_masked(func, ctx, data1, data2, cpu_online_mask);
+ put_online_cpus_atomic();
}
extern unsigned long xcall_sync_tick;
@@ -896,7 +898,7 @@ void smp_flush_dcache_page_impl(struct page *page, int cpu)
atomic_inc(&dcpage_flushes);
#endif
- this_cpu = get_cpu();
+ this_cpu = get_online_cpus_atomic();
if (cpu == this_cpu) {
__local_flush_dcache_page(page);
@@ -922,7 +924,7 @@ void smp_flush_dcache_page_impl(struct page *page, int cpu)
}
}
- put_cpu();
+ put_online_cpus_atomic();
}
void flush_dcache_page_all(struct mm_struct *mm, struct page *page)
@@ -933,7 +935,7 @@ void flush_dcache_page_all(struct mm_struct *mm, struct page *page)
if (tlb_type == hypervisor)
return;
- preempt_disable();
+ get_online_cpus_atomic();
#ifdef CONFIG_DEBUG_DCFLUSH
atomic_inc(&dcpage_flushes);
@@ -958,7 +960,7 @@ void flush_dcache_page_all(struct mm_struct *mm, struct page *page)
}
__local_flush_dcache_page(page);
- preempt_enable();
+ put_online_cpus_atomic();
}
void __irq_entry smp_new_mmu_context_version_client(int irq, struct pt_regs *regs)
@@ -1150,6 +1152,7 @@ void smp_capture(void)
{
int result = atomic_add_ret(1, &smp_capture_depth);
+ get_online_cpus_atomic();
if (result == 1) {
int ncpus = num_online_cpus();
@@ -1166,6 +1169,7 @@ void smp_capture(void)
printk("done\n");
#endif
}
+ put_online_cpus_atomic();
}
void smp_release(void)
--
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