Re: [PATCH v2 3/4] eventfd: simplify eventfd_signal_mask()

Jan Kara
2023-11-22T15:05:40Z

On Wed 22-11-23 13:48:24, Christian Brauner wrote:
> The eventfd_signal_mask() helper was introduced for io_uring and similar
> to eventfd_signal() it always passed 1 for @n. So don't bother with that
> argument at all.
>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Nice. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/eventfd.c | 7 ++++---
> include/linux/eventfd.h | 5 ++---
> io_uring/io_uring.c | 4 ++--
> 3 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/fs/eventfd.c b/fs/eventfd.c
> index dc9e01053235..a9a6de920fb4 100644
> --- a/fs/eventfd.c
> +++ b/fs/eventfd.c
> @@ -43,9 +43,10 @@ struct eventfd_ctx {
> int id;
> };
>
> -__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
> +__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
> {
> unsigned long flags;
> + __u64 n = 1;
>
> /*
> * Deadlock or stack overflow issues can happen if we recurse here
> @@ -68,7 +69,7 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
> current->in_eventfd = 0;
> spin_unlock_irqrestore(&ctx->wqh.lock, flags);
>
> - return n;
> + return n == 1;
> }
>
> /**
> @@ -84,7 +85,7 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask)
> */
> __u64 eventfd_signal(struct eventfd_ctx *ctx)
> {
> - return eventfd_signal_mask(ctx, 1, 0);
> + return eventfd_signal_mask(ctx, 0);
> }
> EXPORT_SYMBOL_GPL(eventfd_signal);
>
> diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
> index 562089431551..4f8aac7eb62a 100644
> --- a/include/linux/eventfd.h
> +++ b/include/linux/eventfd.h
> @@ -36,7 +36,7 @@ struct file *eventfd_fget(int fd);
> struct eventfd_ctx *eventfd_ctx_fdget(int fd);
> struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
> __u64 eventfd_signal(struct eventfd_ctx *ctx);
> -__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask);
> +__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask);
> int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
> __u64 *cnt);
> void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
> @@ -63,8 +63,7 @@ static inline int eventfd_signal(struct eventfd_ctx *ctx)
> return -ENOSYS;
> }
>
> -static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n,
> - unsigned mask)
> +static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
> {
> return -ENOSYS;
> }
> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
> index ed254076c723..70170a41eac4 100644
> --- a/io_uring/io_uring.c
> +++ b/io_uring/io_uring.c
> @@ -558,7 +558,7 @@ static void io_eventfd_ops(struct rcu_head *rcu)
> int ops = atomic_xchg(&ev_fd->ops, 0);
>
> if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT))
> - eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
> + eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
>
> /* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
> * ordering in a race but if references are 0 we know we have to free
> @@ -594,7 +594,7 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx)
> goto out;
>
> if (likely(eventfd_signal_allowed())) {
> - eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
> + eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
> } else {
> atomic_inc(&ev_fd->refs);
> if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))
>
> --
> 2.42.0
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR