diff options
| -rw-r--r-- | fs/aio.c | 58 |
1 files changed, 23 insertions, 35 deletions
diff --git a/fs/aio.c b/fs/aio.c index 6efb7f6cb22e..643db8fc43c5 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -326,7 +326,7 @@ 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; @@ -347,6 +347,20 @@ 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, @@ -358,19 +372,14 @@ 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; @@ -379,9 +388,9 @@ 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; @@ -389,27 +398,6 @@ 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 */ |