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authorJens Axboe <axboe@kernel.dk>2023-12-08 06:06:02 +0300
committerJens Axboe <axboe@kernel.dk>2023-12-12 17:42:57 +0300
commitdc18b89ab113e9c6c7a529316ddf7029fb55132d (patch)
tree682c2a5f7e58b4af465e4e59fba5bf417420e2cf /io_uring/opdef.c
parent055c15626a45b1ebc9f2f34981e705e1af171236 (diff)
downloadlinux-dc18b89ab113e9c6c7a529316ddf7029fb55132d.tar.xz
io_uring/openclose: add support for IORING_OP_FIXED_FD_INSTALL
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>
Diffstat (limited to 'io_uring/opdef.c')
-rw-r--r--io_uring/opdef.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/io_uring/opdef.c b/io_uring/opdef.c
index 799db44283c7..6705634e5f52 100644
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -469,6 +469,12 @@ const struct io_issue_def io_issue_defs[] = {
.prep = io_eopnotsupp_prep,
#endif
},
+ [IORING_OP_FIXED_FD_INSTALL] = {
+ .needs_file = 1,
+ .audit_skip = 1,
+ .prep = io_install_fixed_fd_prep,
+ .issue = io_install_fixed_fd,
+ },
};
const struct io_cold_def io_cold_defs[] = {
@@ -704,6 +710,9 @@ const struct io_cold_def io_cold_defs[] = {
[IORING_OP_FUTEX_WAITV] = {
.name = "FUTEX_WAITV",
},
+ [IORING_OP_FIXED_FD_INSTALL] = {
+ .name = "FIXED_FD_INSTALL",
+ },
};
const char *io_uring_get_opcode(u8 opcode)