[MIPS] Fix buggy use of kmap_coherent.

Assuming the call of kmap_coherent in local_r4k_flush_cache_page doesn't
need fixing this was skipped in fcae549295bcae801ac48fc1c2030ab8cc487020.
Turns out it needed the same change after all.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index c41ea228495..27096751ddc 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -446,6 +446,7 @@ static inline void local_r4k_flush_cache_page(void *args)
         struct page *page = pfn_to_page(fcp_args->pfn);
         int exec = vma->vm_flags & VM_EXEC;
         struct mm_struct *mm = vma->vm_mm;
+        int map_coherent = 0;
         pgd_t *pgdp;
         pud_t *pudp;
         pmd_t *pmdp;
@@ -479,7 +480,9 @@ static inline void local_r4k_flush_cache_page(void *args)
                  * Use kmap_coherent or kmap_atomic to do flushes for
                  * another ASID than the current one.
                  */
-                if (cpu_has_dc_aliases)
+                map_coherent = (cpu_has_dc_aliases &&
+                                page_mapped(page) && !Page_dcache_dirty(page));
+                if (map_coherent)
                         vaddr = kmap_coherent(page, addr);
                 else
                         vaddr = kmap_atomic(page, KM_USER0);
@@ -502,7 +505,7 @@ static inline void local_r4k_flush_cache_page(void *args)
         }
 
         if (vaddr) {
-                if (cpu_has_dc_aliases)
+                if (map_coherent)
                         kunmap_coherent();
                 else
                         kunmap_atomic(vaddr, KM_USER0);