On 10/01/2020 18:47, Jens Axboe wrote:
> This adds support for doing madvise(2) through io_uring. We assume that
> any operation can block, and hence punt everything async. This could be
> improved, but hard to make bullet proof. The async punt ensures it's
> safe.
>
I don't like that it share structs/fields names with fadvise. E.g. madvise's
context is called struct io_fadvise. Could it at least have fadvise_advice filed
in struct io_uring_sqe? io_uring parts of the patchset look good.
Reviewed-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> fs/io_uring.c | 56 ++++++++++++++++++++++++++++++++++-
> include/uapi/linux/io_uring.h | 1 +
> 2 files changed, 56 insertions(+), 1 deletion(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 0b200a7d4ae0..378f97cc2bf2 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -403,7 +403,10 @@ struct io_files_update {
>
> struct io_fadvise {
> struct file *file;
> - u64 offset;
> + union {
> + u64 offset;
> + u64 addr;
> + };
> u32 len;
> u32 advice;
> };
> @@ -682,6 +685,10 @@ static const struct io_op_def io_op_defs[] = {
> /* IORING_OP_FADVISE */
> .needs_file = 1,
> },
> + {
> + /* IORING_OP_MADVISE */
> + .needs_mm = 1,
> + },
> };
>
> static void io_wq_submit_work(struct io_wq_work **workptr);
> @@ -2448,6 +2455,42 @@ static int io_openat(struct io_kiocb *req, struct io_kiocb **nxt,
> return 0;
> }
>
> +static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
> +{
> +#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
> + if (sqe->ioprio || sqe->buf_index || sqe->off)
> + return -EINVAL;
> +
> + req->fadvise.addr = READ_ONCE(sqe->addr);
> + req->fadvise.len = READ_ONCE(sqe->len);
> + req->fadvise.advice = READ_ONCE(sqe->fadvise_advice);
> + return 0;
> +#else
> + return -EOPNOTSUPP;
> +#endif
> +}
> +
> +static int io_madvise(struct io_kiocb *req, struct io_kiocb **nxt,
> + bool force_nonblock)
> +{
> +#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
> + struct io_fadvise *fa = &req->fadvise;
> + int ret;
> +
> + if (force_nonblock)
> + return -EAGAIN;
> +
> + ret = do_madvise(fa->addr, fa->len, fa->advice);
> + if (ret < 0)
> + req_set_fail_links(req);
> + io_cqring_add_event(req, ret);
> + io_put_req_find_next(req, nxt);
> + return 0;
> +#else
> + return -EOPNOTSUPP;
> +#endif
> +}
> +
> static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
> {
> if (sqe->ioprio || sqe->buf_index || sqe->addr)
> @@ -3769,6 +3812,9 @@ static int io_req_defer_prep(struct io_kiocb *req,
> case IORING_OP_FADVISE:
> ret = io_fadvise_prep(req, sqe);
> break;
> + case IORING_OP_MADVISE:
> + ret = io_madvise_prep(req, sqe);
> + break;
> default:
> printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
> req->opcode);
> @@ -3973,6 +4019,14 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
> }
> ret = io_fadvise(req, nxt, force_nonblock);
> break;
> + case IORING_OP_MADVISE:
> + if (sqe) {
> + ret = io_madvise_prep(req, sqe);
> + if (ret)
> + break;
> + }
> + ret = io_madvise(req, nxt, force_nonblock);
> + break;
> default:
> ret = -EINVAL;
> break;
> diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> index f87d8fb42916..7cb6fe0fccd7 100644
> --- a/include/uapi/linux/io_uring.h
> +++ b/include/uapi/linux/io_uring.h
> @@ -88,6 +88,7 @@ enum {
> IORING_OP_READ,
> IORING_OP_WRITE,
> IORING_OP_FADVISE,
> + IORING_OP_MADVISE,
>
> /* this goes last, obviously */
> IORING_OP_LAST,
>
--
Pavel Begunkov
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