--- /dev/null
+From 5984bb9e2b72455e8e5a1925edde3079c9f949be Mon Sep 17 00:00:00 2001
+From: Jens Axboe <axboe@kernel.dk>
+Date: Mon, 1 Apr 2024 11:30:06 -0600
+Subject: io_uring: disable io-wq execution of multishot NOWAIT requests
+
+From: Jens Axboe <axboe@kernel.dk>
+
+Commit bee1d5becdf5bf23d4ca0cd9c6b60bdf3c61d72b upstream.
+
+Do the same check for direct io-wq execution for multishot requests that
+commit 2a975d426c82 did for the inline execution, and disable multishot
+mode (and revert to single shot) if the file type doesn't support NOWAIT,
+and isn't opened in O_NONBLOCK mode. For multishot to work properly, it's
+a requirement that nonblocking read attempts can be done.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ io_uring/io_uring.c | 13 +++++++++----
+ 1 file changed, 9 insertions(+), 4 deletions(-)
+
+--- a/io_uring/io_uring.c
++++ b/io_uring/io_uring.c
+@@ -1964,10 +1964,15 @@ fail:
+ err = -EBADFD;
+ if (!file_can_poll(req->file))
+ goto fail;
+- err = -ECANCELED;
+- if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
+- goto fail;
+- return;
++ if (req->file->f_flags & O_NONBLOCK ||
++ req->file->f_mode & FMODE_NOWAIT) {
++ err = -ECANCELED;
++ if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
++ goto fail;
++ return;
++ } else {
++ req->flags &= ~REQ_F_APOLL_MULTISHOT;
++ }
+ }
+
+ if (req->flags & REQ_F_FORCE_ASYNC) {
--- /dev/null
+From 6fa8da25be5ad285fae51584ce1d461fec42bd94 Mon Sep 17 00:00:00 2001
+From: Pavel Begunkov <asml.silence@gmail.com>
+Date: Fri, 8 Mar 2024 13:55:57 +0000
+Subject: io_uring: refactor DEFER_TASKRUN multishot checks
+
+From: Pavel Begunkov <asml.silence@gmail.com>
+
+Commit e0e4ab52d17096d96c21a6805ccd424b283c3c6d upstream.
+
+We disallow DEFER_TASKRUN multishots from running by io-wq, which is
+checked by individual opcodes in the issue path. We can consolidate all
+it in io_wq_submit_work() at the same time moving the checks out of the
+hot path.
+
+Suggested-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
+Link: https://lore.kernel.org/r/e492f0f11588bb5aa11d7d24e6f53b7c7628afdb.1709905727.git.asml.silence@gmail.com
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ io_uring/io_uring.c | 20 ++++++++++++++++++++
+ io_uring/net.c | 21 ---------------------
+ io_uring/rw.c | 2 --
+ 3 files changed, 20 insertions(+), 23 deletions(-)
+
+--- a/io_uring/io_uring.c
++++ b/io_uring/io_uring.c
+@@ -949,6 +949,8 @@ bool io_fill_cqe_req_aux(struct io_kiocb
+ u64 user_data = req->cqe.user_data;
+ struct io_uring_cqe *cqe;
+
++ lockdep_assert(!io_wq_current_is_worker());
++
+ if (!defer)
+ return __io_post_aux_cqe(ctx, user_data, res, cflags, false);
+
+@@ -1950,6 +1952,24 @@ fail:
+ goto fail;
+ }
+
++ /*
++ * If DEFER_TASKRUN is set, it's only allowed to post CQEs from the
++ * submitter task context. Final request completions are handed to the
++ * right context, however this is not the case of auxiliary CQEs,
++ * which is the main mean of operation for multishot requests.
++ * Don't allow any multishot execution from io-wq. It's more restrictive
++ * than necessary and also cleaner.
++ */
++ if (req->flags & REQ_F_APOLL_MULTISHOT) {
++ err = -EBADFD;
++ if (!file_can_poll(req->file))
++ goto fail;
++ err = -ECANCELED;
++ if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
++ goto fail;
++ return;
++ }
++
+ if (req->flags & REQ_F_FORCE_ASYNC) {
+ bool opcode_poll = def->pollin || def->pollout;
+
+--- a/io_uring/net.c
++++ b/io_uring/net.c
+@@ -78,19 +78,6 @@ struct io_sr_msg {
+ */
+ #define MULTISHOT_MAX_RETRY 32
+
+-static inline bool io_check_multishot(struct io_kiocb *req,
+- unsigned int issue_flags)
+-{
+- /*
+- * When ->locked_cq is set we only allow to post CQEs from the original
+- * task context. Usual request completions will be handled in other
+- * generic paths but multipoll may decide to post extra cqes.
+- */
+- return !(issue_flags & IO_URING_F_IOWQ) ||
+- !(req->flags & REQ_F_APOLL_MULTISHOT) ||
+- !req->ctx->task_complete;
+-}
+-
+ int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+ {
+ struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
+@@ -837,9 +824,6 @@ int io_recvmsg(struct io_kiocb *req, uns
+ (sr->flags & IORING_RECVSEND_POLL_FIRST))
+ return io_setup_async_msg(req, kmsg, issue_flags);
+
+- if (!io_check_multishot(req, issue_flags))
+- return io_setup_async_msg(req, kmsg, issue_flags);
+-
+ retry_multishot:
+ if (io_do_buffer_select(req)) {
+ void __user *buf;
+@@ -935,9 +919,6 @@ int io_recv(struct io_kiocb *req, unsign
+ (sr->flags & IORING_RECVSEND_POLL_FIRST))
+ return -EAGAIN;
+
+- if (!io_check_multishot(req, issue_flags))
+- return -EAGAIN;
+-
+ sock = sock_from_file(req->file);
+ if (unlikely(!sock))
+ return -ENOTSOCK;
+@@ -1386,8 +1367,6 @@ int io_accept(struct io_kiocb *req, unsi
+ struct file *file;
+ int ret, fd;
+
+- if (!io_check_multishot(req, issue_flags))
+- return -EAGAIN;
+ retry:
+ if (!fixed) {
+ fd = __get_unused_fd_flags(accept->flags, accept->nofile);
+--- a/io_uring/rw.c
++++ b/io_uring/rw.c
+@@ -932,8 +932,6 @@ int io_read_mshot(struct io_kiocb *req,
+ */
+ if (!file_can_poll(req->file))
+ return -EBADFD;
+- if (issue_flags & IO_URING_F_IOWQ)
+- return -EAGAIN;
+
+ ret = __io_read(req, issue_flags);
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
