[PATCH] io_uring: Fix return value from alloc_fixed_file_ref_node

[PATCH] io_uring: Fix return value from alloc_fixed_file_ref_node

[Matthew Wilcox (Oracle)]

alloc_fixed_file_ref_node() currently returns an ERR_PTR on failure.
io_sqe_files_unregister() expects it to return NULL and since it can only
return -ENOMEM, it makes more sense to change alloc_fixed_file_ref_node()
to behave that way.

Fixes: 1ffc54220c44 ("io_uring: fix io_sqe_files_unregister() hangs")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/io_uring.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ca46f314640b..d4d3e30331e4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7684,12 +7684,12 @@ static struct fixed_file_ref_node *alloc_fixed_file_ref_node(
 
 	ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
 	if (!ref_node)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
 	if (percpu_ref_init(&ref_node->refs, io_file_data_ref_zero,
 			    0, GFP_KERNEL)) {
 		kfree(ref_node);
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 	}
 	INIT_LIST_HEAD(&ref_node->node);
 	INIT_LIST_HEAD(&ref_node->file_list);
@@ -7783,9 +7783,9 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	}
 
 	ref_node = alloc_fixed_file_ref_node(ctx);
-	if (IS_ERR(ref_node)) {
+	if (!ref_node) {
 		io_sqe_files_unregister(ctx);
-		return PTR_ERR(ref_node);
+		return -ENOMEM;
 	}
 
 	io_sqe_files_set_node(file_data, ref_node);
@@ -7885,8 +7885,8 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 		return -EINVAL;
 
 	ref_node = alloc_fixed_file_ref_node(ctx);
-	if (IS_ERR(ref_node))
-		return PTR_ERR(ref_node);
+	if (!ref_node)
+		return -ENOMEM;
 
 	done = 0;
 	fds = u64_to_user_ptr(up->fds);
-- 
2.29.2

Re: [PATCH] io_uring: Fix return value from alloc_fixed_file_ref_node

[Jens Axboe]

On 1/6/21 9:09 AM, Matthew Wilcox (Oracle) wrote:
> alloc_fixed_file_ref_node() currently returns an ERR_PTR on failure.
> io_sqe_files_unregister() expects it to return NULL and since it can only
> return -ENOMEM, it makes more sense to change alloc_fixed_file_ref_node()
> to behave that way.

Applied, thanks.

-- 
Jens Axboe