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-rw-r--r--fs/aio.c58
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 */