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 930582FF660 for ; Thu, 20 Nov 2025 22:32:50 +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=1763677970; cv=none; b=IajKtY2HDaQ+u0+q1eTeUozrjvJovon6uO3a01Qbq9ODf34RplRfI8iXI/h38+ic93nHTk+mubZupXvhneNzyhfe7Ze0TFSRreEooW6YdMUZdpl5p0SaxPdGeRCaGLiZRhEhZ4Q+jWqkny2uhu3fsXrtHhLrLM9NlU7cViWLDH8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763677970; c=relaxed/simple; bh=O+EXhlRETzrI8VkgUdKtMXFB9wTX0BkWwxsZh4wxqlY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=IuyH0KgIXBW/4lj/8fq9GbMcZPok3/0GIPX0uREpk1iuLNvHEUQV1pL2alauN8+8Mkb6lNWk+WTGoh9mdtjgiwYWtA1f6vuszztTNpgr5jrrNgY9Z1soBoJzBiAGosa+QqBirStYg0bqa5fEvzG5S9UR3bYYmBPcWMtYBBONRoA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WGePl1Jk; 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="WGePl1Jk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1DA6C113D0; Thu, 20 Nov 2025 22:32:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763677970; bh=O+EXhlRETzrI8VkgUdKtMXFB9wTX0BkWwxsZh4wxqlY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=WGePl1Jkmu19I/VtJy51Q1Hzx/OnD5QYcfnmb6pzJdabIHXwCcK9IvFjzPl5ajhCl aZlQ1SNpFBq3k9KbnbfENI2F6qbYtFsD5yOKOUUFnffQQCUQckLTdSOd/yTfNoUqik wnmcr5fuMYnHP1qmzoWVs817kRfkXXF8mJuOmxHUlMHdPdNjb+vaStx/OXvxCmeDcU BFEckRUtRzu0hupjhHCnP0AU+suroQEtW3EvKbTQaAFNyn6oihpvj28/B2PyXK42+H w5yFVljVcsgq/kX+2wbaR1KcPFTLfwOWoIfwaTrnYSYYDf+y0BPNaIRVlzYa6NtpFB nWdedY1YwqvLA== From: Christian Brauner Date: Thu, 20 Nov 2025 23:32:13 +0100 Subject: [PATCH RFC v2 16/48] userfaultfd: convert new_userfaultfd() to FD_PREPARE() 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: <20251120-work-fd-prepare-v2-16-fef6ebda05d3@kernel.org> References: <20251120-work-fd-prepare-v2-0-fef6ebda05d3@kernel.org> In-Reply-To: <20251120-work-fd-prepare-v2-0-fef6ebda05d3@kernel.org> To: Linus Torvalds , Jeff Layton , Amir Goldstein , Jens Axboe 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=1837; i=brauner@kernel.org; h=from:subject:message-id; bh=O+EXhlRETzrI8VkgUdKtMXFB9wTX0BkWwxsZh4wxqlY=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWTKT3tb0K0qxbDGWrFBsGaz3KsuJp/5us+nSpRMsdgVF FegLF/TUcrCIMbFICumyOLQbhIut5ynYrNRpgbMHFYmkCEMXJwCMJHiGQz/q7f8DgxxaLm88dTW RYWcswwUhK7cmhKy96nXl4KWR41OKxgZFq6/8/HrLKnrh2yk7y+6ZqtQEP80eNL1f1md7dOWrru /mQcA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Signed-off-by: Christian Brauner --- fs/userfaultfd.c | 32 +++++++++++--------------------- 1 file changed, 11 insertions(+), 21 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 54c6cc7fe9c6..14f98caeae8e 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 +2133,18 @@ 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(fdf, 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(fdf)) + return fd_prepare_error(fdf); - /* 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); + fd_prepare_file(fdf)->f_mode |= FMODE_NOWAIT; + retain_and_null_ptr(ctx); + return fd_publish(fdf); } - /* 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; } static inline bool userfaultfd_syscall_allowed(int flags) -- 2.47.3