Re: [PATCH 2/2] io_uring: account locked memory before potential error case

[Stefano Garzarella <sgarzare@redhat.com>]

On Wed, Aug 05, 2020 at 01:02:24PM -0600, Jens Axboe wrote:
> The tear down path will always unaccount the memory, so ensure that we
> have accounted it before hitting any of them.
> 
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>  fs/io_uring.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 0d857f7ca507..7c42f63fbb0a 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -8341,6 +8341,14 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
>  	ctx->user = user;
>  	ctx->creds = get_current_cred();
>  
> +	/*
> +	 * Account memory _before_ installing the file descriptor. Once
> +	 * the descriptor is installed, it can get closed at any time.
> +	 */

What about update a bit the comment?
Maybe adding the commit description in this comment.

> +	io_account_mem(ctx, ring_pages(p->sq_entries, p->cq_entries),
> +		       ACCT_LOCKED);
> +	ctx->limit_mem = limit_mem;
> +
>  	ret = io_allocate_scq_urings(ctx, p);
>  	if (ret)
>  		goto err;
> @@ -8377,14 +8385,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
>  		goto err;
>  	}
>  
> -	/*
> -	 * Account memory _before_ installing the file descriptor. Once
> -	 * the descriptor is installed, it can get closed at any time.
> -	 */
> -	io_account_mem(ctx, ring_pages(p->sq_entries, p->cq_entries),
> -		       ACCT_LOCKED);
> -	ctx->limit_mem = limit_mem;
> -
>  	/*
>  	 * Install ring fd as the very last thing, so we don't risk someone
>  	 * having closed it before we finish setup
> -- 
> 2.28.0
> 

Thanks,
Stefano