From: Arjun Roy <arjunroy@xxxxxxxxxx>
pte_index() is either defined as a macro (e.g. sparc64) or as an
inlined function (e.g. x86). vm_insert_pages() depends on pte_index
but it is not defined on all platforms (e.g. m68k).
To fix compilation of vm_insert_pages() on architectures not providing
pte_index(), we perform the following fix:
0. For platforms where it is meaningful, and defined as a macro, no
change is needed.
1. For platforms where it is meaningful and defined as an inlined
function, and we want to use it with vm_insert_pages(), we define
a degenerate macro of the form: #define pte_index pte_index
2. vm_insert_pages() checks for the existence of a pte_index macro
definition. If found, it implements a batched insert. If not found,
it devolves to calling vm_insert_page() in a loop.
This patch implements step 2.
Signed-off-by: Arjun Roy <arjunroy@xxxxxxxxxx>
---
mm/memory.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/mm/memory.c b/mm/memory.c
index d6f834f7d145..33631a5b5c3f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1500,8 +1500,9 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr,
return retval;
}
+#ifdef pte_index
/* insert_pages() amortizes the cost of spinlock operations
- * when inserting pages in a loop.
+ * when inserting pages in a loop. Arch *must* define pte_index.
*/
static int insert_pages(struct vm_area_struct *vma, unsigned long addr,
struct page **pages, unsigned long *num, pgprot_t prot)
@@ -1556,6 +1557,7 @@ static int insert_pages(struct vm_area_struct *vma, unsigned long addr,
*num = remaining_pages_total;
return ret;
}
+#endif /* ifdef pte_index */
/**
* vm_insert_pages - insert multiple pages into user vma, batching the pmd lock.
@@ -1575,6 +1577,7 @@ static int insert_pages(struct vm_area_struct *vma, unsigned long addr,
int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr,
struct page **pages, unsigned long *num)
{
+#ifdef pte_index
const unsigned long end_addr = addr + (*num * PAGE_SIZE) - 1;
if (addr < vma->vm_start || end_addr >= vma->vm_end)
@@ -1586,6 +1589,18 @@ int vm_insert_pages(struct vm_area_struct *vma, unsigned long addr,
}
/* Defer page refcount checking till we're about to map that page. */
return insert_pages(vma, addr, pages, num, vma->vm_page_prot);
+#else
+ unsigned long idx = 0, pgcount = *num;
+ int err;
+
+ for (; idx < pgcount; ++idx) {
+ err = vm_insert_page(vma, addr + (PAGE_SIZE * idx), pages[idx]);
+ if (err)
+ break;
+ }
+ *num = pgcount - idx;
+ return err;
+#endif /* ifdef pte_index */
}
EXPORT_SYMBOL(vm_insert_pages);
--
2.25.1.481.gfbce0eb801-goog
