From: Pavel Begunkov <asml.silence@gmail.com> mainline inclusion from mainline-v6.10-rc2 commit 6746ee4c3a189f8b60694f01e7e29bc5ff7972e0 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ICJPON CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- When an io_uring request needs blocking context we offload it to the io_uring's thread pool called io-wq. We can get there off ->uring_cmd by returning -EAGAIN, but there is no straightforward way of doing that from an asynchronous callback. Add a helper that would transfer a command to a blocking context. Note, we do an extra hop via task_work before io_queue_iowq(), that's a limitation of io_uring infra we have that can likely be lifted later if that would ever become a problem. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/f735f807d7c8ba50c9452c69dfe5d3e9e535037b.172607208... Signed-off-by: Jens Axboe <axboe@kernel.dk> Conflicts: io_uring/uring_cmd.c include/linux/io_uring/cmd.h [Context differences.] Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> Signed-off-by: Long Li <leo.lilong@huawei.com> --- include/linux/io_uring/cmd.h | 6 ++++++ io_uring/io_uring.c | 11 +++++++++++ io_uring/io_uring.h | 1 + io_uring/uring_cmd.c | 7 +++++++ 4 files changed, 25 insertions(+) diff --git a/include/linux/io_uring/cmd.h b/include/linux/io_uring/cmd.h index d69b4038aa3e..2597523dc6ad 100644 --- a/include/linux/io_uring/cmd.h +++ b/include/linux/io_uring/cmd.h @@ -40,6 +40,9 @@ void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd, unsigned int issue_flags); +/* Execute the request from a blocking context */ +void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd); + #else static inline int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, struct iov_iter *iter, void *ioucmd) @@ -59,6 +62,9 @@ static inline void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd, unsigned int issue_flags) { } +static inline void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd) +{ +} #endif /* users must follow the IOU_F_TWQ_LAZY_WAKE semantics */ diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index ec155bd242cd..ca6b6516f75c 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -525,6 +525,17 @@ static void io_queue_iowq(struct io_kiocb *req) io_queue_linked_timeout(link); } +static void io_req_queue_iowq_tw(struct io_kiocb *req, struct io_tw_state *ts) +{ + io_queue_iowq(req); +} + +void io_req_queue_iowq(struct io_kiocb *req) +{ + req->io_task_work.func = io_req_queue_iowq_tw; + io_req_task_work_add(req); +} + static __cold void io_queue_deferred(struct io_ring_ctx *ctx) { while (!list_empty(&ctx->defer_list)) { diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h index c5c454744d18..c8d90d90b6bf 100644 --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -65,6 +65,7 @@ int io_uring_alloc_task_context(struct task_struct *task, int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file, int start, int end); +void io_req_queue_iowq(struct io_kiocb *req); int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts); int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr); diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c index 6420500a051a..edc831cc34ed 100644 --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -199,6 +199,13 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, } EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed); +void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd) +{ + struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); + + io_req_queue_iowq(req); +} + int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags) { struct socket *sock = cmd->file->private_data; -- 2.39.2