Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753303AbaLFPQa (ORCPT ); Sat, 6 Dec 2014 10:16:30 -0500 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:47670 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752266AbaLFPIL (ORCPT ); Sat, 6 Dec 2014 10:08:11 -0500 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nicholas Bellinger , "Michael S. Tsirkin" , Paolo Bonzini , Stefan Hajnoczi , Jiri Slaby Subject: [PATCH 3.12 54/66] vhost-scsi: Take configfs group dependency during VHOST_SCSI_SET_ENDPOINT Date: Sat, 6 Dec 2014 16:07:46 +0100 Message-Id: <32d48b3cc855df95001e80b1dc07adc2079d26fd.1417878427.git.jslaby@suse.cz> X-Mailer: git-send-email 2.1.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nicholas Bellinger 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit ab8edab132829b26dd13db6caca3c242cce35dc1 upstream. This patch addresses a bug where individual vhost-scsi configfs endpoint groups can be removed from below while active exports to QEMU userspace still exist, resulting in an OOPs. It adds a configfs_depend_item() in vhost_scsi_set_endpoint() to obtain an explicit dependency on se_tpg->tpg_group in order to prevent individual vhost-scsi WWPN endpoints from being released via normal configfs methods while an QEMU ioctl reference still exists. Also, add matching configfs_undepend_item() in vhost_scsi_clear_endpoint() to release the dependency, once QEMU's reference to the individual group at /sys/kernel/config/target/vhost/$WWPN/$TPGT is released. (Fix up vhost_scsi_clear_endpoint() error path - DanC) Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Stefan Hajnoczi Signed-off-by: Nicholas Bellinger Signed-off-by: Jiri Slaby --- drivers/vhost/scsi.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index d300fd99a2b8..c5b631cceb4c 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -1194,6 +1194,7 @@ static int vhost_scsi_set_endpoint(struct vhost_scsi *vs, struct vhost_scsi_target *t) { + struct se_portal_group *se_tpg; struct tcm_vhost_tport *tv_tport; struct tcm_vhost_tpg *tpg; struct tcm_vhost_tpg **vs_tpg; @@ -1241,6 +1242,21 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs, ret = -EEXIST; goto out; } + /* + * In order to ensure individual vhost-scsi configfs + * groups cannot be removed while in use by vhost ioctl, + * go ahead and take an explicit se_tpg->tpg_group.cg_item + * dependency now. + */ + se_tpg = &tpg->se_tpg; + ret = configfs_depend_item(se_tpg->se_tpg_tfo->tf_subsys, + &se_tpg->tpg_group.cg_item); + if (ret) { + pr_warn("configfs_depend_item() failed: %d\n", ret); + kfree(vs_tpg); + mutex_unlock(&tpg->tv_tpg_mutex); + goto out; + } tpg->tv_tpg_vhost_count++; tpg->vhost_scsi = vs; vs_tpg[tpg->tport_tpgt] = tpg; @@ -1283,6 +1299,7 @@ static int vhost_scsi_clear_endpoint(struct vhost_scsi *vs, struct vhost_scsi_target *t) { + struct se_portal_group *se_tpg; struct tcm_vhost_tport *tv_tport; struct tcm_vhost_tpg *tpg; struct vhost_virtqueue *vq; @@ -1331,6 +1348,13 @@ vhost_scsi_clear_endpoint(struct vhost_scsi *vs, vs->vs_tpg[target] = NULL; match = true; mutex_unlock(&tpg->tv_tpg_mutex); + /* + * Release se_tpg->tpg_group.cg_item configfs dependency now + * to allow vhost-scsi WWPN se_tpg->tpg_group shutdown to occur. + */ + se_tpg = &tpg->se_tpg; + configfs_undepend_item(se_tpg->se_tpg_tfo->tf_subsys, + &se_tpg->tpg_group.cg_item); } if (match) { for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) { -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/