From mboxrd@z Thu Jan 1 00:00:00 1970 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 A673433E37D for ; Tue, 18 Nov 2025 15:50:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763481010; cv=none; b=k5rwyPDtijdige1Qos3J8MuLCxVLGHPVvy/0LuMqoC21CfTGa+xH8y1wjJISRk/3t3EWxTwDTiXR0USr5n5LLfoMjhpYFtxTScOkoa1PTHlrlH4C1QyL9YZJm3erqJJxFv19EK4TGiO2zrnWQz2scMYGWU0JcQAcjqmV/Bm7RlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763481010; c=relaxed/simple; bh=I7h9T64gaHheuh30/P9JJqAq11eWmCk8+OVh7JKGy7M=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=diWbaQm1a4acY538Ly8BLeIV5/z0kBKF4QO2iRio1xXRUvIxW4QtVwqgaVR0eeU5yvG6naZDieDe6oe8hlgczF3QokzBxdJunMhfTO0tTOU3e9cg9L8OVmyLsp6eY1n4cbsipeQ0OU/JZ+iuB6+hpDoJsZ1v8+AstEUg2KFLYz8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XBz9OKGo; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XBz9OKGo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C876C2BCB5; Tue, 18 Nov 2025 15:50:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763481010; bh=I7h9T64gaHheuh30/P9JJqAq11eWmCk8+OVh7JKGy7M=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=XBz9OKGoYTjrO7oGYoVgCs9eWXskmdzXfTUsGjDay9IsaBtPEShY0lwbHZesYGQ4Q yRCDNnSsimbOhy2+cOwZ20TH7IIx5wAHS9NfBHvxLtHzMpzPyj2BcXC7jLvo8Q9qKR 3S7BtrqQ32LFPscEidq2VkVi13DJ6AtNJLLKo746NE5wsoqJBHMj8VO9+HpM55Vlyk Vau6VovO72z9ZBbbEsSVQ8S0mnI5GlGlfKe+w64odjbalUIBT1gbwRcxVnmfaVxJ8l Agez3MOyGQP8YjCkG33+5y2WFZNm8RCLwHS+tAI1wIGft6K/4gNhHbUD32Af2B2X45 G5ga9ibKdwf+A== From: Christian Brauner Date: Tue, 18 Nov 2025 16:48:56 +0100 Subject: [PATCH DRAFT RFC UNTESTED 16/18] fs: userfaultfd Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20251118-work-fd-prepare-v1-16-c20504d97375@kernel.org> References: <20251118-work-fd-prepare-v1-0-c20504d97375@kernel.org> In-Reply-To: <20251118-work-fd-prepare-v1-0-c20504d97375@kernel.org> To: Linus Torvalds Cc: Alexander Viro , Jan Kara , linux-fsdevel@vger.kernel.org, Christian Brauner X-Mailer: b4 0.15-dev-a6db3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1808; i=brauner@kernel.org; h=from:subject:message-id; bh=I7h9T64gaHheuh30/P9JJqAq11eWmCk8+OVh7JKGy7M=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWTKTO1/uui7S+w9S08N6ZlOebk3ir7aph44f/xmdPRcq wQ/Nd8lHaUsDGJcDLJiiiwO7Sbhcst5KjYbZWrAzGFlAhnCwMUpABNhCGJkONUi0tCYxXxDZcX3 wE/CsqcYTobM9eG42idUs/i1yfTuEwx/uNw8NJ1mnS+Lm65sWT2Zudzhopxeyvnm3cfLd7Arsqx jAQA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Placeholder commit message. Signed-off-by: Christian Brauner --- fs/userfaultfd.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 54c6cc7fe9c6..77048b86d781 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -2111,9 +2111,7 @@ static void init_once_userfaultfd_ctx(void *mem) static int new_userfaultfd(int flags) { - struct userfaultfd_ctx *ctx; - struct file *file; - int fd; + struct userfaultfd_ctx *ctx __free(kfree) = NULL; VM_WARN_ON_ONCE(!current->mm); @@ -2135,26 +2133,17 @@ static int new_userfaultfd(int flags) atomic_set(&ctx->mmap_changing, 0); ctx->mm = current->mm; - fd = get_unused_fd_flags(flags & UFFD_SHARED_FCNTL_FLAGS); - if (fd < 0) - goto err_out; + FD_PREPARE(fdprep, flags & UFFD_SHARED_FCNTL_FLAGS, + anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx, + O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL)); + if (fd_prepare_failed(fdprep)) + return fd_prepare_error(fdprep); - /* Create a new inode so that the LSM can block the creation. */ - file = anon_inode_create_getfile("[userfaultfd]", &userfaultfd_fops, ctx, - O_RDONLY | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL); - if (IS_ERR(file)) { - put_unused_fd(fd); - fd = PTR_ERR(file); - goto err_out; - } /* prevent the mm struct to be freed */ mmgrab(ctx->mm); - file->f_mode |= FMODE_NOWAIT; - fd_install(fd, file); - return fd; -err_out: - kmem_cache_free(userfaultfd_ctx_cachep, ctx); - return fd; + fd_prepare_file(fdprep)->f_mode |= FMODE_NOWAIT; + retain_and_null_ptr(ctx); + return fd_publish(fdprep); } static inline bool userfaultfd_syscall_allowed(int flags) -- 2.47.3