[PATCH] ppc64: Fix the lazy icache/dcache code for non-RAM pages

For some stupid reason I can't explain (brown paper bag is at hand), I
removed the check pfn_valid() in the code that does the icache/dcache
coherency on POWER4 and later. That causes us to eventually try to
access non existing struct page when hashing in IO pages.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 3d83c3b84f0e..22e474876133 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -507,6 +507,9 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
 {
         struct page *page;
 
+        if (!pfn_valid(pte_pfn(pte)))
+                return pp;
+
         page = pte_page(pte);
 
         /* page is dirty */