From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 040D4C88E7F for ; Tue, 15 Sep 2026 11:38:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=GNDTkXQI7mGdcVaT7SDrw9M8MIqod2XUSoHG2zw3J2w=; b=DTfDBZvTaF6pB8A1xCG5nPWDmb hGZIhwstBfxoVMvCWuqU3cBdCYD4NwpUC0Cqek5NIrYTkejapMdtC1yjdqDXrXnnd3KKrLMuYtJ6M wOnf4yEOnpYGEfPosb/UiWn30ujrT0psPCiuzclZHbcgm8TYggj6w32AtS2eDd21bEN4WR0/c7TLR omFIwqBERaj063MNZ0+VMRV4KgE1Z4OOMJ8xaw39mqUTVZt70D9zM6x8n6SZQvhHji7bMVOd/dH5t hNsq11cyKEaHkt/4LBWW1wbjvdGefXJJRN2Dw8z2eqXtJGZPIv0aOYkb6mH4U9PWT3yWl/GtYjrSW B7qKgrVw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6RU1-00000006FNf-0trP; Tue, 15 Sep 2026 11:37:53 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6RTy-00000006FFL-1T58; Tue, 15 Sep 2026 11:37:50 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 9D1E3602C4; Tue, 15 Sep 2026 11:37:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DDE2E1F00898; Tue, 15 Sep 2026 11:37:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789472269; bh=GNDTkXQI7mGdcVaT7SDrw9M8MIqod2XUSoHG2zw3J2w=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=nIsDG6msZxm9ifdIIaNBb4DSvDwZjxBexDpBy0k5+c0EEQRfRNHCnvgHTIY4Q0gZ4 5Y4GAqy+82PffLbcvJlnpDdJKam2a1RZ/lmTtWzv5yc2Qa3CGs1EC2lgotUwdrCtPN R+e8tN55H2q/lzjefH/7MqxCwUMd/aRzXVOqaq/JIPnIQz/fh1lk4mDieRcetKm0Vz We6QD5SZZpeWs1skjtjC95uTXtri2f8p0027MOwC2PJ2AtBz1eyxEa8oFwDdJ/4IbQ 1oi4l5RBwZ4QhEmCd9i4/Ab6QCou55Lo2D/xSrTRR5npBOhYvLPf8mp8Z+7okOyPo6 hMky5BV0f8Xcg== From: Christian Brauner Date: Tue, 15 Sep 2026 13:31:36 +0200 Subject: [PATCH RFC POC 50/50] Drivers: hv: mshv: stop putting descriptors back on failure MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260915-work-fd-reserve-unify-folded-v1-50-4d5217d6b246@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=3018; i=brauner@kernel.org; h=from:subject:message-id; bh=SzeXPqGJtllJZEGwqHGcwxzZWYTunmeJfrbckytXGkI=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWSt1KmPkjZIUeG9e+1R07epv8QvrSgMsrt/1D2tpUnF+ Ty/n9jUjlIWBjEuBlkxRRaHdpNwueU8FZuNMjVg5rAygQxh4OIUgIlo3mb4Hx4+8+W/E5svyCgt bpvwatmUgujlCXflfc2DLyvdmH/HYCPDH44Jiw0OZie7VZtm8ZzaXLrdzmx2uNpNg59n94iEL7/ iyAIA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Rely on the fd exit path machinery. Signed-off-by: Christian Brauner (Amutable) --- drivers/hv/mshv_root_main.c | 27 +++++++-------------------- drivers/hv/mshv_vtl_main.c | 20 +++++--------------- 2 files changed, 12 insertions(+), 35 deletions(-) diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c index cc2cfce2aefd..c95cee0bae85 100644 --- a/drivers/hv/mshv_root_main.c +++ b/drivers/hv/mshv_root_main.c @@ -1072,8 +1072,6 @@ mshv_partition_ioctl_create_vp(struct mshv_partition *partition, struct mshv_vp *vp; struct page *intercept_msg_page, *register_page, *ghcb_page; struct hv_stats_page *stats_pages[2]; - struct file *file; - int fd; long ret; if (copy_from_user(&args, arg, sizeof(args))) @@ -1148,19 +1146,14 @@ mshv_partition_ioctl_create_vp(struct mshv_partition *partition, if (ret) goto put_partition; - fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC); - if (fd < 0) { - ret = fd; + FD_PREPARE(fdf, O_RDWR | O_CLOEXEC, + anon_inode_getfile("mshv_vp", &mshv_vp_fops, vp, + O_RDWR | O_CLOEXEC)); + if (IS_ERR(fdf)) { + ret = PTR_ERR(fdf); goto remove_debugfs_vp; } - file = anon_inode_getfile("mshv_vp", &mshv_vp_fops, vp, - O_RDWR | O_CLOEXEC); - if (IS_ERR(file)) { - ret = PTR_ERR(file); - goto put_unused_vp_fd; - } - /* already exclusive with the partition mutex for all ioctls */ partition->pt_vp_count++; /* @@ -1171,17 +1164,11 @@ mshv_partition_ioctl_create_vp(struct mshv_partition *partition, */ smp_store_release(&partition->pt_vp_array[args.vp_index], vp); - /* - * fd_install() is the userspace-visibility commit point. Must be the - * last operation that can fail or be observed. - */ - fd_install(fd, file); - ret = fd; + /* The syscall exit installs the file; nothing after this can fail. */ + ret = fd_prepare_fd(fdf); goto out; -put_unused_vp_fd: - put_unused_fd(fd); remove_debugfs_vp: mshv_debugfs_vp_remove(vp); put_partition: diff --git a/drivers/hv/mshv_vtl_main.c b/drivers/hv/mshv_vtl_main.c index 6e3c11c68171..f14203d76da1 100644 --- a/drivers/hv/mshv_vtl_main.c +++ b/drivers/hv/mshv_vtl_main.c @@ -114,29 +114,19 @@ static long mshv_ioctl_create_vtl(void __user *user_arg, struct device *module_dev) { struct mshv_vtl *vtl; - struct file *file; - int fd; vtl = kzalloc_obj(*vtl); if (!vtl) return -ENOMEM; - fd = get_unused_fd_flags(O_CLOEXEC); - if (fd < 0) { - kfree(vtl); - return fd; - } - file = anon_inode_getfile("mshv_vtl", &mshv_vtl_fops, - vtl, O_RDWR); - if (IS_ERR(file)) { - put_unused_fd(fd); + FD_PREPARE(fdf, O_CLOEXEC, + anon_inode_getfile("mshv_vtl", &mshv_vtl_fops, vtl, O_RDWR)); + if (IS_ERR(fdf)) { kfree(vtl); - return PTR_ERR(file); + return PTR_ERR(fdf); } vtl->module_dev = module_dev; - fd_install(fd, file); - - return fd; + return fd_prepare_fd(fdf); } static long -- 2.53.0