Re: [PATCH v2 2/2] io_uring: add support for zone-append

Pavel Begunkov
2020-06-25T19:42:05Z

On 25/06/2020 20:15, Kanchan Joshi wrote:
> From: Selvakumar S <selvakuma.s1@samsung.com>
>
> For zone-append, block-layer will return zone-relative offset via ret2
> of ki_complete interface. Make changes to collect it, and send to
> user-space using ceq->flags.
> Detect and report early error if zone-append is requested with
> fixed-buffers.
>
> Signed-off-by: Selvakumar S <selvakuma.s1@samsung.com>
> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
> Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
> Signed-off-by: Javier Gonzalez <javier.gonz@samsung.com>
> ---
> fs/io_uring.c | 32 ++++++++++++++++++++++++++++++--
> 1 file changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 155f3d8..31a9da58 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -402,6 +402,8 @@ struct io_rw {
> struct kiocb kiocb;
> u64 addr;
> u64 len;
> + /* zone-relative offset for append, in sectors */
> + u32 append_offset;
> };
>
> struct io_connect {
> @@ -541,6 +543,7 @@ enum {
> REQ_F_NO_FILE_TABLE_BIT,
> REQ_F_QUEUE_TIMEOUT_BIT,
> REQ_F_WORK_INITIALIZED_BIT,
> + REQ_F_ZONE_APPEND_BIT,
>
> /* not a real bit, just to check we're not overflowing the space */
> __REQ_F_LAST_BIT,
> @@ -598,6 +601,8 @@ enum {
> REQ_F_QUEUE_TIMEOUT = BIT(REQ_F_QUEUE_TIMEOUT_BIT),
> /* io_wq_work is initialized */
> REQ_F_WORK_INITIALIZED = BIT(REQ_F_WORK_INITIALIZED_BIT),
> + /* to return zone relative offset for zone append*/
> + REQ_F_ZONE_APPEND = BIT(REQ_F_ZONE_APPEND_BIT),

Do we need a new flag? We can check for IOCB_ZONE_APPEND, flags are always
close by in req->rw.kiocb.ki_flags. May require to be careful about not
setting it for read, so not screwing buf select.

> };
>
> struct async_poll {
> @@ -1745,6 +1750,8 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
>
> if (req->flags & REQ_F_BUFFER_SELECTED)
> cflags = io_put_kbuf(req);
> + if (req->flags & REQ_F_ZONE_APPEND)
> + cflags = req->rw.append_offset;
>
> __io_cqring_fill_event(req, req->result, cflags);
> (*nr_events)++;
> @@ -1943,7 +1950,7 @@ static inline void req_set_fail_links(struct io_kiocb *req)
> req->flags |= REQ_F_FAIL_LINK;
> }
>
> -static void io_complete_rw_common(struct kiocb *kiocb, long res)
> +static void io_complete_rw_common(struct kiocb *kiocb, long res, long res2)
> {
> struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
> int cflags = 0;
> @@ -1953,8 +1960,14 @@ static void io_complete_rw_common(struct kiocb *kiocb, long res)
>
> if (res != req->result)
> req_set_fail_links(req);
> +
> if (req->flags & REQ_F_BUFFER_SELECTED)
> cflags = io_put_kbuf(req);
> +
> + /* use cflags to return zone append completion result */
> + if (req->flags & REQ_F_ZONE_APPEND)
> + cflags = res2;
> +
> __io_cqring_add_event(req, res, cflags);
> }
>
> @@ -1962,7 +1975,7 @@ static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
> {
> struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
>
> - io_complete_rw_common(kiocb, res);
> + io_complete_rw_common(kiocb, res, res2);
> io_put_req(req);
> }
>
> @@ -1975,6 +1988,9 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
>
> if (res != req->result)
> req_set_fail_links(req);
> + if (req->flags & REQ_F_ZONE_APPEND)
> + req->rw.append_offset = res2;
> +
> req->result = res;
> if (res != -EAGAIN)
> WRITE_ONCE(req->iopoll_completed, 1);
> @@ -2127,6 +2143,9 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
> if (kiocb->ki_flags & IOCB_NOWAIT)
> req->flags |= REQ_F_NOWAIT;
>
> + if (kiocb->ki_flags & IOCB_ZONE_APPEND)
> + req->flags |= REQ_F_ZONE_APPEND;
> +
> if (force_nonblock)
> kiocb->ki_flags |= IOCB_NOWAIT;
>
> @@ -2409,6 +2428,14 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
>
> opcode = req->opcode;
> if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
> + /*
> + * fixed-buffers not supported for zone-append.
> + * This check can be removed when block-layer starts
> + * supporting append with iov_iter of bvec type
> + */
> + if (req->flags == REQ_F_ZONE_APPEND)

s/==/&/

> + return -EINVAL;
> +
> *iovec = NULL;
> return io_import_fixed(req, rw, iter);
> }
> @@ -2704,6 +2731,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock)
> req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT;
>
> req->result = 0;
> +

Extra \n

> io_size = ret;
> if (req->flags & REQ_F_LINK_HEAD)
> req->result = io_size;
>

--
Pavel Begunkov