[PATCH 2/2] fs/aio.c: use get_user_pages_non_movable() to pin ring pages when support memory hotremove

[Lin Feng <linfeng@cn.fujitsu.com>]

This patch gets around the aio ring pages can't be migrated bug caused by
get_user_pages() via using the new function. It only works as configed with
CONFIG_MEMORY_HOTREMOVE, otherwise it uses the old version of get_user_pages().

Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
---
 fs/aio.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/aio.c b/fs/aio.c
index 71f613c..0e9b30a 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -138,9 +138,15 @@ static int aio_setup_ring(struct kioctx *ctx)
 	}
 
 	dprintk("mmap address: 0x%08lx\n", info->mmap_base);
+#ifdef CONFIG_MEMORY_HOTREMOVE
+	info->nr_pages = get_user_pages_non_movable(current, ctx->mm,
+					info->mmap_base, nr_pages,
+					1, 0, info->ring_pages, NULL);
+#else
 	info->nr_pages = get_user_pages(current, ctx->mm,
 					info->mmap_base, nr_pages, 
 					1, 0, info->ring_pages, NULL);
+#endif
 	up_write(&ctx->mm->mmap_sem);
 
 	if (unlikely(info->nr_pages != nr_pages)) {
-- 
1.7.11.7