From patchwork Wed Nov 22 12:48:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 13464791 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 45D2B495FB; Wed, 22 Nov 2023 12:50:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fcF4pxKR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 467BDC433CB; Wed, 22 Nov 2023 12:49:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1700657408; bh=aU2J72Xp3JKGs0IOk/3BX7BmnbVjjSktFzc5W0fL98s=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=fcF4pxKRziGSAF2FOqxImPOzC2PEVz+iXrlHdDaPyM6/v6o+f16jjdAN+lC2pUX0Z c6Vj4pEReJ7qSGBsgd/Etcb/Bx/NFbs8vsXFZDe0htqh1OD5+o81eDXmshIPtuoyBK lUfl8SFejNcIDe347vDzewRE22FCt1MWsk2CM4stuQE/3LK9tJj9skrI0zg5sl10Ot aC+S7ghlxwZ2rYR03/mACnTcLYZ3VnGDGFga1iJsrVdoW+9CIorT0HYAGwO2anWZen uIJ0oJqCh8DfwGg5lQlRhQShmsIUNUkRjdY2uwh1ov0dsfb3jgNLqtI1PY54/gVbLF del/29joBTz5A== From: Christian Brauner Date: Wed, 22 Nov 2023 13:48:25 +0100 Subject: [PATCH v2 4/4] eventfd: make eventfd_signal{_mask}() void Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20231122-vfs-eventfd-signal-v2-4-bd549b14ce0c@kernel.org> References: <20231122-vfs-eventfd-signal-v2-0-bd549b14ce0c@kernel.org> In-Reply-To: <20231122-vfs-eventfd-signal-v2-0-bd549b14ce0c@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: 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 , Christian Brauner , 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 X-Mailer: b4 0.13-dev-26615 X-Developer-Signature: v=1; a=openpgp-sha256; l=3854; i=brauner@kernel.org; h=from:subject:message-id; bh=aU2J72Xp3JKGs0IOk/3BX7BmnbVjjSktFzc5W0fL98s=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMaTG/lj73/5dRNiNYIfwQ9VnNb8kSHjtMQlc94/11mwNB qlLZUUiHaUsDGJcDLJiiiwO7Sbhcst5KjYbZWrAzGFlAhnCwMUpABP5zcjwh+t1UN76vf945tSW T/rxjCHQpq4w94r2Zqm/ATIn/7GqSjMyvH01XYi3/rDPbk7Hf182bChuXbCzsfD2+Wr+47+PXN/ CxAMA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 No caller care about the return value. Signed-off-by: Christian Brauner Reviewed-by: Jan Kara --- 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 */