dc18b89ab1
io_uring can currently open/close regular files or fixed/direct descriptors. Or you can instantiate a fixed descriptor from a regular one, and then close the regular descriptor. But you currently can't turn a purely fixed/direct descriptor into a regular file descriptor. IORING_OP_FIXED_FD_INSTALL adds support for installing a direct descriptor into the normal file table, just like receiving a file descriptor or opening a new file would do. This is all nicely abstracted into receive_fd(), and hence adding support for this is truly trivial. Since direct descriptors are only usable within io_uring itself, it can be useful to turn them into real file descriptors if they ever need to be accessed via normal syscalls. This can either be a transitory thing, or just a permanent transition for a given direct descriptor. By default, new fds are installed with O_CLOEXEC set. The application can disable O_CLOEXEC by setting IORING_FIXED_FD_NO_CLOEXEC in the sqe->install_fd_flags member. Suggested-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
18 lines
754 B
C
18 lines
754 B
C
// SPDX-License-Identifier: GPL-2.0
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int __io_close_fixed(struct io_ring_ctx *ctx, unsigned int issue_flags,
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unsigned int offset);
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int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
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int io_openat(struct io_kiocb *req, unsigned int issue_flags);
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void io_open_cleanup(struct io_kiocb *req);
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int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
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int io_openat2(struct io_kiocb *req, unsigned int issue_flags);
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int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
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int io_close(struct io_kiocb *req, unsigned int issue_flags);
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int io_install_fixed_fd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
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int io_install_fixed_fd(struct io_kiocb *req, unsigned int issue_flags);
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