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Wed, 22 Nov 2023 15:06:43 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id ZtuBLgMZXmXgGgAAMHmgww (envelope-from ); Wed, 22 Nov 2023 15:06:43 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 4E863A07DC; Wed, 22 Nov 2023 16:06:43 +0100 (CET) Date: Wed, 22 Nov 2023 16:06:43 +0100 From: Jan Kara To: Christian Brauner Cc: linux-fsdevel@vger.kernel.org, Christoph Hellwig , Jan Kara , Vitaly Kuznetsov , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, David Woodhouse , Paul Durrant , Oded Gabbay , Wu Hao , Tom Rix , Moritz Fischer , Xu Yilun , Zhenyu Wang , Zhi Wang , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Daniel Vetter , Leon Romanovsky , Jason Gunthorpe , Frederic Barrat , Andrew Donnellan , Arnd Bergmann , Greg Kroah-Hartman , Eric Farman , Matthew Rosato , Halil Pasic , Vineeth Vijayan , Peter Oberparleiter , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Tony Krowiak , Jason Herne , Harald Freudenberger , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Diana Craciun , Alex Williamson , Eric Auger , Fei Li , Benjamin LaHaise , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Kirti Wankhede , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fpga@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-rdma@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-usb@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-aio@kvack.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Jens Axboe , Pavel Begunkov , io-uring@vger.kernel.org Subject: Re: [PATCH v2 4/4] eventfd: make eventfd_signal{_mask}() void Message-ID: <20231122150643.5b57p5yxhfuxa764@quack3> References: <20231122-vfs-eventfd-signal-v2-0-bd549b14ce0c@kernel.org> <20231122-vfs-eventfd-signal-v2-4-bd549b14ce0c@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231122-vfs-eventfd-signal-v2-4-bd549b14ce0c@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 396298030A X-Stat-Signature: ecz4np181rrx8ay4krhu4x6yxb1wdd7q X-HE-Tag: 1700665605-601338 X-HE-Meta: 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 x/m5gfyK sKyNHGk6qpMhg766cayKy7LIv8rbNrOxvZS8J4LckgZWDftxBRhfL4lofSFPqkoe6gGNumvi9SQnOi+HlLQLXgHXjC7bWmvp6S0jkWFVcBP/DG5IF7wu9JaVxECmz5p9XXQk3BEL8P1SF+5qL9wQIKuJH4zN5Q5EnmXRokkeUwLBKVvk/TAuZK0dIHc/vk/rbahcRWb/BhDJrtYeQkVYiXUnr6lZYqxEE4g6dQYHem5AvSLQw33BHPDUepi9xDO1ShY2QfUl2lwYzjqdLl00nhv+D7L2GB4I0lquMRIQGJTh7+v3zT2gvDA76b4kByHxCGwrhqdiucaPanzQtTdGcSnJVetzKCWrjzf8PaiR4jwFfAJ8cxUkgYzeu+rpekG1G2Tze7ubqLNL3Fqtrs2CK1nHxMHgK5s/POVWsRon/fBGKbO08pl9+f9gmyg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed 22-11-23 13:48:25, Christian Brauner wrote: > No caller care about the return value. > > Signed-off-by: Christian Brauner Yup. Feel free to add: Reviewed-by: Jan Kara 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 SUSE Labs, CR