openrisc: Fix pagewalk usage in arch_dma_{clear, set}_uncached

Since commit 8782fb61cc848 ("mm: pagewalk: Fix race between unmap and page
walker"), walk_page_range() on kernel ranges won't work anymore,
walk_page_range_novma() must be used instead.

Note: I don't have an openrisc development setup, so this is completely
untested.

Fixes: 8782fb61cc848 ("mm: pagewalk: Fix race between unmap and page walker")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
index a82b2ca..b3edbb3 100644 (file)
--- a/arch/openrisc/kernel/dma.c
+++ b/arch/openrisc/kernel/dma.c
@@ -74,10 +74,10 @@ void *arch_dma_set_uncached(void *cpu_addr, size_t size)
         * We need to iterate through the pages, clearing the dcache for
         * them and setting the cache-inhibit bit.
         */
-       mmap_read_lock(&init_mm);
-       error = walk_page_range(&init_mm, va, va + size, &set_nocache_walk_ops,
-                       NULL);
-       mmap_read_unlock(&init_mm);
+       mmap_write_lock(&init_mm);
+       error = walk_page_range_novma(&init_mm, va, va + size,
+                       &set_nocache_walk_ops, NULL, NULL);
+       mmap_write_unlock(&init_mm);
 
        if (error)
                return ERR_PTR(error);
@@ -88,11 +88,11 @@ void arch_dma_clear_uncached(void *cpu_addr, size_t size)
 {
        unsigned long va = (unsigned long)cpu_addr;
 
-       mmap_read_lock(&init_mm);
+       mmap_write_lock(&init_mm);
        /* walk_page_range shouldn't be able to fail here */
-       WARN_ON(walk_page_range(&init_mm, va, va + size,
-                       &clear_nocache_walk_ops, NULL));
-       mmap_read_unlock(&init_mm);
+       WARN_ON(walk_page_range_novma(&init_mm, va, va + size,
+                       &clear_nocache_walk_ops, NULL, NULL));
+       mmap_write_unlock(&init_mm);
 }
 
 void arch_sync_dma_for_device(phys_addr_t addr, size_t size,