[PATCH] mm: split highorder pages

Have an explicit mm call to split higher order pages into individual pages.
 Should help to avoid bugs and be more explicit about the code's intention.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/ppc/kernel/dma-mapping.c b/arch/ppc/kernel/dma-mapping.c
index 685fd0defe23..61465ec88bc7 100644
--- a/arch/ppc/kernel/dma-mapping.c
+++ b/arch/ppc/kernel/dma-mapping.c
@@ -223,6 +223,8 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
                 pte_t *pte = consistent_pte + CONSISTENT_OFFSET(vaddr);
                 struct page *end = page + (1 << order);
 
+                split_page(page, order);
+
                 /*
                  * Set the "dma handle"
                  */
@@ -231,7 +233,6 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
                 do {
                         BUG_ON(!pte_none(*pte));
 
-                        set_page_count(page, 1);
                         SetPageReserved(page);
                         set_pte_at(&init_mm, vaddr,
                                    pte, mk_pte(page, pgprot_noncached(PAGE_KERNEL)));
@@ -244,7 +245,6 @@ __dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp)
                  * Free the otherwise unused pages.
                  */
                 while (page < end) {
-                        set_page_count(page, 1);
                         __free_page(page);
                         page++;
                 }