public inbox for [email protected]
 help / color / mirror / Atom feed
From: Jan Kara <[email protected]>
To: Christian Brauner <[email protected]>
Cc: [email protected], Christoph Hellwig <[email protected]>,
	Jan Kara <[email protected]>, Vitaly Kuznetsov <[email protected]>,
	Sean Christopherson <[email protected]>,
	Paolo Bonzini <[email protected]>,
	Thomas Gleixner <[email protected]>,
	Ingo Molnar <[email protected]>, Borislav Petkov <[email protected]>,
	Dave Hansen <[email protected]>,
	[email protected], David Woodhouse <[email protected]>,
	Paul Durrant <[email protected]>, Oded Gabbay <[email protected]>,
	Wu Hao <[email protected]>, Tom Rix <[email protected]>,
	Moritz Fischer <[email protected]>, Xu Yilun <[email protected]>,
	Zhenyu Wang <[email protected]>,
	Zhi Wang <[email protected]>,
	Jani Nikula <[email protected]>,
	Joonas Lahtinen <[email protected]>,
	Rodrigo Vivi <[email protected]>,
	Tvrtko Ursulin <[email protected]>,
	David Airlie <[email protected]>, Daniel Vetter <[email protected]>,
	Leon Romanovsky <[email protected]>, Jason Gunthorpe <[email protected]>,
	Frederic Barrat <[email protected]>,
	Andrew Donnellan <[email protected]>,
	Arnd Bergmann <[email protected]>,
	Greg Kroah-Hartman <[email protected]>,
	Eric Farman <[email protected]>,
	Matthew Rosato <[email protected]>,
	Halil Pasic <[email protected]>,
	Vineeth Vijayan <[email protected]>,
	Peter Oberparleiter <[email protected]>,
	Heiko Carstens <[email protected]>,
	Vasily Gorbik <[email protected]>,
	Alexander Gordeev <[email protected]>,
	Christian Borntraeger <[email protected]>,
	Sven Schnelle <[email protected]>,
	Tony Krowiak <[email protected]>,
	Jason Herne <[email protected]>,
	Harald Freudenberger <[email protected]>,
	"Michael S. Tsirkin" <[email protected]>,
	Jason Wang <[email protected]>,
	Xuan Zhuo <[email protected]>,
	Diana Craciun <[email protected]>,
	Alex Williamson <[email protected]>,
	Eric Auger <[email protected]>, Fei Li <[email protected]>,
	Benjamin LaHaise <[email protected]>,
	Johannes Weiner <[email protected]>,
	Michal Hocko <[email protected]>,
	Roman Gushchin <[email protected]>,
	Shakeel Butt <[email protected]>,
	Muchun Song <[email protected]>,
	Kirti Wankhede <[email protected]>,
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected],
	[email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	Jens Axboe <[email protected]>,
	Pavel Begunkov <[email protected]>,
	[email protected]
Subject: Re: [PATCH v2 4/4] eventfd: make eventfd_signal{_mask}() void
Date: Wed, 22 Nov 2023 16:06:43 +0100	[thread overview]
Message-ID: <20231122150643.5b57p5yxhfuxa764@quack3> (raw)
In-Reply-To: <[email protected]>

On Wed 22-11-23 13:48:25, Christian Brauner wrote:
> No caller care about the return value.
> 
> Signed-off-by: Christian Brauner <[email protected]>

Yup. Feel free to add:

Reviewed-by: Jan Kara <[email protected]>

								Honza

> ---
>  fs/eventfd.c            | 40 +++++++++++++++-------------------------
>  include/linux/eventfd.h | 16 +++++++---------
>  2 files changed, 22 insertions(+), 34 deletions(-)
> 
> diff --git a/fs/eventfd.c b/fs/eventfd.c
> index a9a6de920fb4..13be2fb7fc96 100644
> --- a/fs/eventfd.c
> +++ b/fs/eventfd.c
> @@ -43,10 +43,19 @@ struct eventfd_ctx {
>  	int id;
>  };
>  
> -__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
> +/**
> + * eventfd_signal - Adds @n to the eventfd counter.
> + * @ctx: [in] Pointer to the eventfd context.
> + * @mask: [in] poll mask
> + *
> + * This function is supposed to be called by the kernel in paths that do not
> + * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
> + * value, and we signal this as overflow condition by returning a EPOLLERR
> + * to poll(2).
> + */
> +void 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
> @@ -57,37 +66,18 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask)
>  	 * safe context.
>  	 */
>  	if (WARN_ON_ONCE(current->in_eventfd))
> -		return 0;
> +		return;
>  
>  	spin_lock_irqsave(&ctx->wqh.lock, flags);
>  	current->in_eventfd = 1;
> -	if (ULLONG_MAX - ctx->count < n)
> -		n = ULLONG_MAX - ctx->count;
> -	ctx->count += n;
> +	if (ctx->count < ULLONG_MAX)
> +		ctx->count++;
>  	if (waitqueue_active(&ctx->wqh))
>  		wake_up_locked_poll(&ctx->wqh, EPOLLIN | mask);
>  	current->in_eventfd = 0;
>  	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
> -
> -	return n == 1;
> -}
> -
> -/**
> - * eventfd_signal - Adds @n to the eventfd counter.
> - * @ctx: [in] Pointer to the eventfd context.
> - *
> - * This function is supposed to be called by the kernel in paths that do not
> - * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX
> - * value, and we signal this as overflow condition by returning a EPOLLERR
> - * to poll(2).
> - *
> - * Returns the amount by which the counter was incremented.
> - */
> -__u64 eventfd_signal(struct eventfd_ctx *ctx)
> -{
> -	return eventfd_signal_mask(ctx, 0);
>  }
> -EXPORT_SYMBOL_GPL(eventfd_signal);
> +EXPORT_SYMBOL_GPL(eventfd_signal_mask);
>  
>  static void eventfd_free_ctx(struct eventfd_ctx *ctx)
>  {
> diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
> index 4f8aac7eb62a..fea7c4eb01d6 100644
> --- a/include/linux/eventfd.h
> +++ b/include/linux/eventfd.h
> @@ -35,8 +35,7 @@ void eventfd_ctx_put(struct eventfd_ctx *ctx);
>  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, __poll_t mask);
> +void 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);
> @@ -58,14 +57,8 @@ static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
>  	return ERR_PTR(-ENOSYS);
>  }
>  
> -static inline int eventfd_signal(struct eventfd_ctx *ctx)
> +static inline void eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
>  {
> -	return -ENOSYS;
> -}
> -
> -static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, unsigned mask)
> -{
> -	return -ENOSYS;
>  }
>  
>  static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
> @@ -91,5 +84,10 @@ static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
>  
>  #endif
>  
> +static inline void eventfd_signal(struct eventfd_ctx *ctx)
> +{
> +	eventfd_signal_mask(ctx, 0);
> +}
> +
>  #endif /* _LINUX_EVENTFD_H */
>  
> 
> -- 
> 2.42.0
> 
-- 
Jan Kara <[email protected]>
SUSE Labs, CR

  reply	other threads:[~2023-11-22 15:06 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-22 12:48 [PATCH v2 0/4] eventfd: simplify signal helpers Christian Brauner
2023-11-22 12:48 ` [PATCH v2 1/4] i915: make inject_virtual_interrupt() void Christian Brauner
2023-11-22 15:05   ` Jan Kara
2023-11-23  0:24   ` Zhenyu Wang
2023-11-23 13:11     ` Christian Brauner
2023-11-22 12:48 ` [PATCH v2 2/4] eventfd: simplify eventfd_signal() Christian Brauner
2023-11-22 14:49   ` Xu Yilun
2023-11-22 15:05   ` Jan Kara
2023-11-22 15:19   ` Jani Nikula
2023-11-23 13:18     ` Christian Brauner
2023-11-24  2:02   ` Andrew Donnellan
2023-11-27 16:17   ` Eric Farman
2024-02-06 19:44   ` Stefan Hajnoczi
2024-02-07 14:33     ` Anthony Krowiak
2024-02-07 14:34   ` Paolo Bonzini
2024-02-08  9:02     ` Christian Brauner
2023-11-22 12:48 ` [PATCH v2 3/4] eventfd: simplify eventfd_signal_mask() Christian Brauner
2023-11-22 15:05   ` Jan Kara
2023-11-22 12:48 ` [PATCH v2 4/4] eventfd: make eventfd_signal{_mask}() void Christian Brauner
2023-11-22 15:06   ` Jan Kara [this message]
2023-11-23 19:43 ` [PATCH v2 0/4] eventfd: simplify signal helpers Jens Axboe
2023-11-24  7:47 ` Christian Brauner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20231122150643.5b57p5yxhfuxa764@quack3 \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox