From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 468E74A4850; Tue, 15 Sep 2026 11:34:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789472058; cv=none; b=lR1eyR5KElOQCRxP3WS7Yt1VXZIgrDdEUhT1Nj7OPwOuL/CjsfiFgJk1A2zul04MeuBxXStODUw6m/WREeiwNdPpfTBPU6zm4X6ham+vKbNPpomPHnBoz8Ychf4UWveosj96+Qy3TIssE4iAfld4Gwku0fUpzJ3/8Q85LDxVHlo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789472058; c=relaxed/simple; bh=9JAnV65R8KRKKJ6YuAvXjbfOJ9otGL1j9hOaIwPGraE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=UQ5B/hJkKwc2JJCe8296ThymMTcRnheX0+dd/us6NF81q6S3IgF20LmlT/hVK9el59i7LrwnfdivfvYV1IjeJ/3ufPXs5v5lwJxuEGCDUC8uaMrrEJ73IslUe7/oS/FxrsNSGbBjDGE5YCMD1LRH/MkI2HxA0jYKQww2rdxi2/8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lOHGXy8c; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lOHGXy8c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F2821F0089A; Tue, 15 Sep 2026 11:34:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789472056; bh=bA4ynAEQWzLS8TLe1OyiMNmBCpxqZtxYswH6/3xEJn0=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=lOHGXy8cA8jMMGugeuqOHZsHNH9R6NCpiW1SGzSqk2TyhtRX4C5vLan9jF9Lg4sJM A2A2QCI68wPGNuvnvsrzBxBe+YzlBhd/5q0D0YjdRbOCeZ4h8kXDe3U7+UuYQS9gSN nEwgErx77J2ER2m1k0BupFTZUzEnThzBPGlrZZvpU1Un3NXwFxcQXOSeuFbFE3Jgku eXAGNFsAkifaZ03d/z3uqPrGplip5My3/DUaiek0wZjCAPE/m4YXJ55H3MQW+eeCW6 5funLtKEK3ijtyLwLxFdU4Hr4SHgxA1Jfy6H6zqgczgxiU00tDcHkC1P9UYL1yAfe1 +SqeWUaLUrpuA== From: Christian Brauner Date: Tue, 15 Sep 2026 13:31:09 +0200 Subject: [PATCH RFC POC 23/50] file: open-code receive_fd()'s immediate install Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260915-work-fd-reserve-unify-folded-v1-23-4d5217d6b246@kernel.org> References: <20260915-work-fd-reserve-unify-folded-v1-0-4d5217d6b246@kernel.org> In-Reply-To: <20260915-work-fd-reserve-unify-folded-v1-0-4d5217d6b246@kernel.org> To: Linus Torvalds Cc: Alexander Viro , Jann Horn , Jan Kara , Ingo Molnar , Peter Zijlstra , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Oleg Nesterov , linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, Jens Axboe , io-uring@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-gpio@vger.kernel.org, linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, bpf@vger.kernel.org, David Airlie , virtualization@lists.linux.dev, kvm@vger.kernel.org, kexec@lists.infradead.org, linux-hyperv@vger.kernel.org, "Christian Brauner (Amutable)" X-Mailer: b4 0.17-dev-db0b7 X-Developer-Signature: v=1; a=openpgp-sha256; l=1378; i=brauner@kernel.org; h=from:subject:message-id; bh=9JAnV65R8KRKKJ6YuAvXjbfOJ9otGL1j9hOaIwPGraE=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWSt1KllfvjTfp2zVVTgt9NTTlxN9shpKt3NzyD6qO520 LPPTxYs7yhlYRDjYpAVU2RxaDcJl1vOU7HZKFMDZg4rE8gQBi5OAZjI1CCG/yUL4597uxz9uSVv B5MCM+uUS19mlk6c3GQWOy8v+s8XQzOGv5ILE+KOSk0/EKpzUmdZprjQ2jqtG2qZb/98t1fIsHn zhgcA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 receive_fd() cannot defer to syscall exit as SECCOMP_IOCTL_NOTIF_ADDFD installs into the target task and hands the number to the supervisor and IORING_OP_FIXED_FD_INSTALL runs from an io_uring op. Open-code the get_unused_fd_flags() + fd_install() it did through FD_PREPARE(). Signed-off-by: Christian Brauner (Amutable) --- fs/file.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/fs/file.c b/fs/file.c index 2b041b45f225..1f06d0c846c2 100644 --- a/fs/file.c +++ b/fs/file.c @@ -1607,25 +1607,27 @@ int replace_fd(unsigned fd, struct file *file, unsigned flags) */ int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags) { - int error; + int fd, error; error = security_file_receive(file); if (error) return error; - FD_PREPARE(fdf, o_flags, file); - if (fdf.err) - return fdf.err; - get_file(file); + fd = get_unused_fd_flags(o_flags); + if (fd < 0) + return fd; if (ufd) { - error = put_user(fd_prepare_fd(fdf), ufd); - if (error) + error = put_user(fd, ufd); + if (error) { + put_unused_fd(fd); return error; + } } - __receive_sock(fd_prepare_file(fdf)); - return fd_publish(fdf); + __receive_sock(file); + fd_install(fd, get_file(file)); + return fd; } EXPORT_SYMBOL_GPL(receive_fd); -- 2.53.0