1 files changed, 23 insertions, 35 deletions

diff --git a/fs/aio.c b/fs/aio.c
index efa708b29054..062a5f6a1448 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -362,7 +362,7 @@ static int aio_setup_ring(struct kioctx *ctx)
         struct aio_ring *ring;
         unsigned nr_events = ctx->max_reqs;
         struct mm_struct *mm = current->mm;
-        unsigned long size, populate;
+        unsigned long size, unused;
         int nr_pages;
         int i;
         struct file *file;
@@ -383,6 +383,20 @@ static int aio_setup_ring(struct kioctx *ctx)
                 return -EAGAIN;
         }
 
+        ctx->aio_ring_file = file;
+        nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
+                        / sizeof(struct io_event);
+
+        ctx->ring_pages = ctx->internal_pages;
+        if (nr_pages > AIO_RING_PAGES) {
+                ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
+                                          GFP_KERNEL);
+                if (!ctx->ring_pages) {
+                        put_aio_ring_file(ctx);
+                        return -ENOMEM;
+                }
+        }
+
         for (i = 0; i < nr_pages; i++) {
                 struct page *page;
                 page = find_or_create_page(file->f_inode->i_mapping,
@@ -394,19 +408,14 @@ static int aio_setup_ring(struct kioctx *ctx)
                 SetPageUptodate(page);
                 SetPageDirty(page);
                 unlock_page(page);
+
+                ctx->ring_pages[i] = page;
         }
-        ctx->aio_ring_file = file;
-        nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
-                        / sizeof(struct io_event);
+        ctx->nr_pages = i;
 
-        ctx->ring_pages = ctx->internal_pages;
-        if (nr_pages > AIO_RING_PAGES) {
-                ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
-                                          GFP_KERNEL);
-                if (!ctx->ring_pages) {
-                        put_aio_ring_file(ctx);
-                        return -ENOMEM;
-                }
+        if (unlikely(i != nr_pages)) {
+                aio_free_ring(ctx);
+                return -EAGAIN;
         }
 
         ctx->mmap_size = nr_pages * PAGE_SIZE;
@@ -415,9 +424,9 @@ static int aio_setup_ring(struct kioctx *ctx)
         down_write(&mm->mmap_sem);
         ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size,
                                        PROT_READ | PROT_WRITE,
-                                       MAP_SHARED | MAP_POPULATE, 0, &populate);
+                                       MAP_SHARED, 0, &unused);
+        up_write(&mm->mmap_sem);
         if (IS_ERR((void *)ctx->mmap_base)) {
-                up_write(&mm->mmap_sem);
                 ctx->mmap_size = 0;
                 aio_free_ring(ctx);
                 return -EAGAIN;
@@ -425,27 +434,6 @@ static int aio_setup_ring(struct kioctx *ctx)
 
         pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
 
-        /* We must do this while still holding mmap_sem for write, as we
-         * need to be protected against userspace attempting to mremap()
-         * or munmap() the ring buffer.
-         */
-        ctx->nr_pages = get_user_pages(current, mm, ctx->mmap_base, nr_pages,
-                                       1, 0, ctx->ring_pages, NULL);
-
-        /* Dropping the reference here is safe as the page cache will hold
-         * onto the pages for us.  It is also required so that page migration
-         * can unmap the pages and get the right reference count.
-         */
-        for (i = 0; i < ctx->nr_pages; i++)
-                put_page(ctx->ring_pages[i]);
-
-        up_write(&mm->mmap_sem);
-
-        if (unlikely(ctx->nr_pages != nr_pages)) {
-                aio_free_ring(ctx);
-                return -EAGAIN;
-        }
-
         ctx->user_id = ctx->mmap_base;
         ctx->nr_events = nr_events; /* trusted copy */