[PATCH] io_uring: set error code to be ENOMEM when io_alloc_async_ctx() fails

[PATCH] io_uring: set error code to be ENOMEM when io_alloc_async_ctx() fails

[Xiaoguang Wang]

We should return ENOMEM for memory allocation failures, fix this
issue for io_alloc_async_ctx() calls.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
---
 fs/io_uring.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6ac830b2b4fb..42a49a7e7792 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4993,7 +4993,7 @@ static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		return 0;
 
 	if (!req->io && io_alloc_async_ctx(req))
-		return -EAGAIN;
+		return -ENOMEM;
 
 	ret = io_req_defer_prep(req, sqe);
 	if (ret < 0)
@@ -5695,7 +5695,7 @@ static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 			ctx->drain_next = 1;
 		}
 		if (io_alloc_async_ctx(req)) {
-			ret = -EAGAIN;
+			ret = -ENOMEM;
 			goto err_req;
 		}
 
@@ -5723,7 +5723,7 @@ static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 			INIT_LIST_HEAD(&req->link_list);
 
 			if (io_alloc_async_ctx(req)) {
-				ret = -EAGAIN;
+				ret = -ENOMEM;
 				goto err_req;
 			}
 			ret = io_req_defer_prep(req, sqe);
-- 
2.17.2

Re: [PATCH] io_uring: set error code to be ENOMEM when io_alloc_async_ctx() fails

[Jens Axboe]

On 4/8/20 7:48 PM, Xiaoguang Wang wrote:
> We should return ENOMEM for memory allocation failures, fix this
> issue for io_alloc_async_ctx() calls.

It's not uncommon to have out-of-memory turn into -EAGAIN for the
application for runtime allocations, indicating that the application
could feasibly try again and hope for a better outcome (maybe after
freeing memory).

The error code is also documented as such in the io_uring_enter.2
man page.

-- 
Jens Axboe

Re: [PATCH] io_uring: set error code to be ENOMEM when io_alloc_async_ctx() fails

[Xiaoguang Wang]

hi,

> On 4/8/20 7:48 PM, Xiaoguang Wang wrote:
>> We should return ENOMEM for memory allocation failures, fix this
>> issue for io_alloc_async_ctx() calls.
> 
> It's not uncommon to have out-of-memory turn into -EAGAIN for the
> application for runtime allocations, indicating that the application
> could feasibly try again and hope for a better outcome (maybe after
> freeing memory).
OK, i see, thanks.

> 
> The error code is also documented as such in the io_uring_enter.2
> man page.
Yeah, I checked it just now, and I should read the man page carefully again :)

Regards,
Xiaoguang Wang

>