kernel/linux.git/io_uring/eventfd.c, branch v6.19.11

io_uring/eventfd: use ctx->rings_rcu for flags checking

2026-03-19T15:15:33+00:00

Commit 177c69432161f6e4bab07ccacf8a1748a6898a6b upstream. Similarly to what commit e78f7b70e837 did for local task work additions, use ->rings_rcu under RCU rather than dereference ->rings directly. See that commit for more details. Cc: stable@vger.kernel.org Fixes: 79cfe9e59c2a ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/eventfd: open code io_eventfd_grab()

2025-04-24T14:33:54+00:00

io_eventfd_grab() doesn't help wit understanding the path, it'll be simpler to keep the helper open coded. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/5cb53ce3876c2819db9e8055cf41dca4398521db.1745493845.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/eventfd: clean up rcu locking

2025-04-24T14:33:54+00:00

Conditional locking is never welcome if there are better options. Move rcu locking into io_eventfd_signal(), make it unconditional and use guards. It also helps with sparse warnings. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/91a925e708ca8a5aa7fee61f96d29b24ea9adeaf.1745493845.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/eventfd: dedup signalling helpers

2025-04-24T14:33:54+00:00

Consolidate io_eventfd_flush_signal() and io_eventfd_signal(). Not much of a difference for now, but it prepares it for following changes. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/5beecd4da65d8d2d83df499196f84b329387f6a2.1745493845.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period

2025-01-09T14:16:45+00:00

io_eventfd_do_signal() is invoked from an RCU callback, but when dropping the reference to the io_ev_fd, it calls io_eventfd_free() directly if the refcount drops to zero. This isn't correct, as any potential freeing of the io_ev_fd should be deferred another RCU grace period. Just call io_eventfd_put() rather than open-code the dec-and-test and free, which will correctly defer it another RCU grace period. Fixes: 21a091b970cd ("io_uring: signal registered eventfd to process deferred task work") Reported-by: Jann Horn Cc: stable@vger.kernel.org Tested-by: Li Zetao Reviewed-by: Li Zetao Reviewed-by: Prasanna Kumar T S M Signed-off-by: Jens Axboe

io_uring/eventfd: move ctx->evfd_last_cq_tail into io_ev_fd

2024-10-29T19:43:26+00:00

Everything else about the io_uring eventfd support is nicely kept private to that code, except the cached_cq_tail tracking. With everything else in place, move io_eventfd_flush_signal() to using the ev_fd grab+release helpers, which then enables the direct use of io_ev_fd for this tracking too. Link: https://lore.kernel.org/r/20240921080307.185186-7-axboe@kernel.dk Signed-off-by: Jens Axboe

io_uring/eventfd: abstract out ev_fd grab + release helpers

2024-10-29T19:43:26+00:00

In preparation for needing the ev_fd grabbing (and releasing) from another path, abstract out two helpers for that. Link: https://lore.kernel.org/r/20240921080307.185186-6-axboe@kernel.dk Signed-off-by: Jens Axboe

io_uring/eventfd: move trigger check into a helper

2024-10-29T19:43:26+00:00

It's a bit hard to read what guards the triggering, move it into a helper and add a comment explaining it too. This additionally moves the ev_fd == NULL check in there as well. Link: https://lore.kernel.org/r/20240921080307.185186-5-axboe@kernel.dk Signed-off-by: Jens Axboe

io_uring/eventfd: move actual signaling part into separate helper

2024-10-29T19:43:26+00:00

In preparation for using this from multiple spots, move the signaling into a helper. Link: https://lore.kernel.org/r/20240921080307.185186-4-axboe@kernel.dk Signed-off-by: Jens Axboe

io_uring/eventfd: check for the need to async notifier earlier

2024-10-29T19:43:26+00:00

It's not necessary to do this post grabbing a reference. With that, we can drop the out goto path as well. Link: https://lore.kernel.org/r/20240921080307.185186-3-axboe@kernel.dk Signed-off-by: Jens Axboe