[PATCH v2 4/7] alpha: invalidate the local context in flush_tlb_page()

[Magnus Lindholm <linmag7@gmail.com>]

When the target mm is not current, flush_tlb_page() does nothing locally,
and smp_call_function() reaches only the other CPUs. This CPU may still
hold translations for the mm and can later reuse the old ASN together with
them.

Add the missing else branch. flush_tlb_other() clears mm->context[cpu] so
a fresh ASN is taken at the next switch.  With the previous patch this also
covers a lazily borrowed mm, which no longer takes the targeted path.

The uniprocessor implementations of flush_tlb_mm() and
flush_icache_user_page() in asm/tlbflush.h and asm/cacheflush.h already
contain exactly this branch.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
 arch/alpha/kernel/smp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 7856d23b3384..a5a42ae4a7d8 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -698,6 +698,9 @@ flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
 			preempt_enable();
 			return;
 		}
+	} else {
+		/* smp_call_function() does not call back into this CPU.  */
+		flush_tlb_other(mm);
 	}
 
 	data.vma = vma;
-- 
2.53.0