On 9/14/21 9:12 AM, Pavel Begunkov wrote:
> It might be inconvenient that direct open/accept deviates from the
> update semantics and fails if the slot is taken instead of removing a
> file sitting there. Implement this auto-removal.
>
> Note that removal might need to allocate and so may fail. However, if an
> empty slot is specified, it's guaraneed to not fail on the fd
> installation side for valid userspace programs. It's needed for users
> who can't tolerate such failures, e.g. accept where the other end
> never retries.
>
> Suggested-by: Franz-B. Tuneke <franz-bernhard.tuneke@xxxxxxxxxxxxxx>
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> ---
>
> v2: simplify io_rsrc_node_switch_start() handling
>
> fs/io_uring.c | 52 +++++++++++++++++++++++++++++++++------------------
> 1 file changed, 34 insertions(+), 18 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index a864a94364c6..58c0cbfdd128 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -8287,11 +8287,27 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
> #endif
> }
>
> +static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
> + struct io_rsrc_node *node, void *rsrc)
> +{
> + struct io_rsrc_put *prsrc;
> +
> + prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
> + if (!prsrc)
> + return -ENOMEM;
> +
> + prsrc->tag = *io_get_tag_slot(data, idx);
> + prsrc->rsrc = rsrc;
> + list_add(&prsrc->list, &node->rsrc_list);
> + return 0;
> +}
I know this code is just being moved, but I tend to like making the
expected/fast path inline:
prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
if (prsrc) {
prsrc->tag = *io_get_tag_slot(data, idx);
prsrc->rsrc = rsrc;
list_add(&prsrc->list, &node->rsrc_list);
return 0;
}
return -ENOMEM;
--
Jens Axboe
