x86_64 remote tlb invalidation

Reading through arch/x86/kernel/tlb_64.c, I've been wondering why the code for native_flush_tlb_others() can't be simplified as follows:

@@ -180,7 +180,7 @@
 
 	f->flush_mm = mm;
 	f->flush_va = va;
-	cpus_or(f->flush_cpumask, cpumask, f->flush_cpumask);
+	f->flush_cpumask = cpumask;
 
 	/*
 	 * Make the above memory operations globally visible before

My reasoning:

* The previous invocation of native_flush_tlb_others() waited for f->flush_cpumask to be cleared before it unlocked f->tlbstate_lock;

* sets bits in the flush_cpumask field of union smp_flush_state without holding the correwsponding tlbstate_lock;

* Therefore, f->flush_cpumask must still be cleared when the next invocation of native_flush_tlb_others() reacquires f->tlbstate_lock.

I don't think I missed anything, did I ?

Thanks,

Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.

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