[PATCH v2 44/45] sparc: Use get/put_online_cpus_atomic() to prevent CPU offline
From: Srivatsa S. Bhat <hidden>
Date: 2013-06-25 20:37:23
Also in:
linux-arch, linux-pm, linuxppc-dev, lkml, sparclinux
Subsystem:
sparc + ultrasparc (sparc/sparc64), the rest · Maintainers:
"David S. Miller", Andreas Larsson, Linus Torvalds
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@davemloft.net> Cc: Sam Ravnborg <redacted> Cc: Thomas Gleixner <redacted> Cc: Dave Kleikamp <redacted> Cc: sparclinux@vger.kernel.org Signed-off-by: Srivatsa S. Bhat <redacted> --- 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)