hi,
Forgot to add "Suggested-by: Hao Xu <howeyxu@xxxxxxxxxxx>". If this
patch can be merged directly, please kindly add this, thanks.
Regards,
Xiaoguang Wang
> One big issue with file registration feature is that it needs user
> space apps to maintain free slot info about io_uring's fixed file
> table, which really is a burden for development. Now since io_uring
> starts to choose free file slot for user space apps by using
> IORING_FILE_INDEX_ALLOC flag in accept or open operations, but they
> need app to uses direct accept or direct open, which as far as I know,
> some apps are not prepared to use direct accept or open yet.
>
> To support apps, who still need real fds, use registration feature
> easier, let IORING_OP_FILES_UPDATE support to choose fixed file slots,
> which will store picked fixed files slots in fd array and let cqe return
> the number of slots allocated.
>
> Signed-off-by: Xiaoguang Wang <xiaoguang.wang@xxxxxxxxxxxxxxxxx>
> ---
> fs/io_uring.c | 85 +++++++++++++++++++++++++++++++++++--------
> include/uapi/linux/io_uring.h | 1 +
> 2 files changed, 70 insertions(+), 16 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 6d91148e9679..58514b8048da 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -574,6 +574,7 @@ struct io_close {
> struct file *file;
> int fd;
> u32 file_slot;
> + u32 flags;
> };
>
> struct io_timeout_data {
> @@ -1366,7 +1367,9 @@ static int io_req_prep_async(struct io_kiocb *req);
>
> static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
> unsigned int issue_flags, u32 slot_index);
> -static int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags);
> +static int __io_close_fixed(struct io_kiocb *req, unsigned int issue_flags,
> + unsigned int offset);
> +static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags);
>
> static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer);
> static void io_eventfd_signal(struct io_ring_ctx *ctx);
> @@ -5945,16 +5948,20 @@ static int io_statx(struct io_kiocb *req, unsigned int issue_flags)
> return 0;
> }
>
> +#define IORING_CLOSE_FD_AND_FILE_SLOT 1
> +
> static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
> {
> - if (sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index)
> + if (sqe->off || sqe->addr || sqe->len || sqe->buf_index)
> return -EINVAL;
> if (req->flags & REQ_F_FIXED_FILE)
> return -EBADF;
>
> req->close.fd = READ_ONCE(sqe->fd);
> req->close.file_slot = READ_ONCE(sqe->file_index);
> - if (req->close.file_slot && req->close.fd)
> + req->close.flags = READ_ONCE(sqe->close_flags);
> + if (!(req->close.flags & IORING_CLOSE_FD_AND_FILE_SLOT) &&
> + req->close.file_slot && req->close.fd)
> return -EINVAL;
>
> return 0;
> @@ -5970,7 +5977,8 @@ static int io_close(struct io_kiocb *req, unsigned int issue_flags)
>
> if (req->close.file_slot) {
> ret = io_close_fixed(req, issue_flags);
> - goto err;
> + if (ret || !(req->close.flags & IORING_CLOSE_FD_AND_FILE_SLOT))
> + goto err;
> }
>
> spin_lock(&files->file_lock);
> @@ -8003,23 +8011,63 @@ static int io_files_update_prep(struct io_kiocb *req,
> return 0;
> }
>
> +static int io_files_update_with_index_alloc(struct io_kiocb *req,
> + unsigned int issue_flags)
> +{
> + __s32 __user *fds = u64_to_user_ptr(req->rsrc_update.arg);
> + struct file *file;
> + unsigned int done, nr_fds = req->rsrc_update.nr_args;
> + int ret, fd;
> +
> + for (done = 0; done < nr_fds; done++) {
> + if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
> + ret = -EFAULT;
> + break;
> + }
> +
> + file = fget(fd);
> + if (!file) {
> + ret = -EBADF;
> + goto out;
> + }
> + ret = io_fixed_fd_install(req, issue_flags, file,
> + IORING_FILE_INDEX_ALLOC);
> + if (ret < 0)
> + goto out;
> + if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
> + ret = -EFAULT;
> + __io_close_fixed(req, issue_flags, ret);
> + break;
> + }
> + }
> +
> +out:
> + if (done)
> + return done;
> + return ret;
> +}
> +
> static int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
> {
> struct io_ring_ctx *ctx = req->ctx;
> struct io_uring_rsrc_update2 up;
> int ret;
>
> - up.offset = req->rsrc_update.offset;
> - up.data = req->rsrc_update.arg;
> - up.nr = 0;
> - up.tags = 0;
> - up.resv = 0;
> - up.resv2 = 0;
> + if (req->rsrc_update.offset == IORING_FILE_INDEX_ALLOC) {
> + ret = io_files_update_with_index_alloc(req, issue_flags);
> + } else {
> + up.offset = req->rsrc_update.offset;
> + up.data = req->rsrc_update.arg;
> + up.nr = 0;
> + up.tags = 0;
> + up.resv = 0;
> + up.resv2 = 0;
>
> - io_ring_submit_lock(ctx, issue_flags);
> - ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
> - &up, req->rsrc_update.nr_args);
> - io_ring_submit_unlock(ctx, issue_flags);
> + io_ring_submit_lock(ctx, issue_flags);
> + ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
> + &up, req->rsrc_update.nr_args);
> + io_ring_submit_unlock(ctx, issue_flags);
> + }
>
> if (ret < 0)
> req_set_fail(req);
> @@ -10183,9 +10231,9 @@ static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
> return ret;
> }
>
> -static int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
> +static int __io_close_fixed(struct io_kiocb *req, unsigned int issue_flags,
> + unsigned int offset)
> {
> - unsigned int offset = req->close.file_slot - 1;
> struct io_ring_ctx *ctx = req->ctx;
> struct io_fixed_file *file_slot;
> struct file *file;
> @@ -10222,6 +10270,11 @@ static int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
> return ret;
> }
>
> +static inline int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
> +{
> + return __io_close_fixed(req, issue_flags, req->close.file_slot - 1);
> +}
> +
> static int __io_sqe_files_update(struct io_ring_ctx *ctx,
> struct io_uring_rsrc_update2 *up,
> unsigned nr_args)
> diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> index 53e7dae92e42..e347b3fea4e4 100644
> --- a/include/uapi/linux/io_uring.h
> +++ b/include/uapi/linux/io_uring.h
> @@ -47,6 +47,7 @@ struct io_uring_sqe {
> __u32 unlink_flags;
> __u32 hardlink_flags;
> __u32 xattr_flags;
> + __u32 close_flags;
> };
> __u64 user_data; /* data to be passed back at completion time */
> /* pack this to avoid bogus arm OABI complaints */
