From patchwork Sat Apr 13 03:29:14 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Asias He X-Patchwork-Id: 2440031 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id A32AFDF2A1 for ; Sat, 13 Apr 2013 03:29:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755187Ab3DMD3i (ORCPT ); Fri, 12 Apr 2013 23:29:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1534 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754830Ab3DMD3d (ORCPT ); Fri, 12 Apr 2013 23:29:33 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r3D3TUhx016469 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 12 Apr 2013 23:29:30 -0400 Received: from hj.localdomain.com (vpn1-114-201.nay.redhat.com [10.66.114.201]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r3D3TG99025413; Fri, 12 Apr 2013 23:29:26 -0400 From: Asias He To: Nicholas Bellinger Cc: Paolo Bonzini , Stefan Hajnoczi , "Michael S. Tsirkin" , Rusty Russell , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, target-devel@vger.kernel.org, Asias He Subject: [PATCH v4 2/2] tcm_vhost: Wait for pending requests in vhost_scsi_flush() Date: Sat, 13 Apr 2013 11:29:14 +0800 Message-Id: <1365823754-27730-3-git-send-email-asias@redhat.com> In-Reply-To: <1365823754-27730-1-git-send-email-asias@redhat.com> References: <1365823754-27730-1-git-send-email-asias@redhat.com> In-Reply-To: <20130412113331.GD23467@redhat.com> References: <20130412113331.GD23467@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This patch makes vhost_scsi_flush() wait for all the pending requests issued before the flush operation to be finished. Changes in v4: - Introduce vhost_scsi_inflight - Drop array to track flush - Use RCU to protect vs_inflight explicitly Changes in v3: - Rebase - Drop 'tcm_vhost: Wait for pending requests in vhost_scsi_clear_endpoint()' in this series, we already did that in 'tcm_vhost: Use vq->private_data to indicate if the endpoint is setup' Changes in v2: - Increase/Decrease inflight requests in vhost_scsi_{allocate,free}_cmd and tcm_vhost_{allocate,free}_evt Signed-off-by: Asias He --- drivers/vhost/tcm_vhost.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++ drivers/vhost/tcm_vhost.h | 5 ++++ 2 files changed, 78 insertions(+) diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c index e09f0fe..5dde525 100644 --- a/drivers/vhost/tcm_vhost.c +++ b/drivers/vhost/tcm_vhost.c @@ -74,6 +74,11 @@ enum { #define VHOST_SCSI_MAX_VQ 128 #define VHOST_SCSI_MAX_EVENT 128 +struct vhost_scsi_inflight { + wait_queue_head_t wait; + atomic_t count; +}; + struct vhost_scsi { /* Protected by vhost_scsi->dev.mutex */ struct tcm_vhost_tpg **vs_tpg; @@ -91,6 +96,8 @@ struct vhost_scsi { struct mutex vs_events_lock; /* protect vs_events_dropped,events_nr */ bool vs_events_dropped; /* any missed events */ int vs_events_nr; /* num of pending events */ + + struct vhost_scsi_inflight __rcu *vs_inflight; /* track inflight req */ }; /* Local pointer to allocated TCM configfs fabric module */ @@ -108,6 +115,51 @@ static int iov_num_pages(struct iovec *iov) ((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT; } +static struct vhost_scsi_inflight * +tcm_vhost_alloc_inflight(struct vhost_scsi *vs) +{ + struct vhost_scsi_inflight *inflight; + + inflight = kzalloc(sizeof(*inflight), GFP_KERNEL); + if (inflight) { + atomic_set(&inflight->count, 0); + init_waitqueue_head(&inflight->wait); + } + rcu_assign_pointer(vs->vs_inflight, inflight); + synchronize_rcu(); + + return inflight; +} + +static struct vhost_scsi_inflight * +tcm_vhost_inc_inflight(struct vhost_scsi *vs) +{ + struct vhost_scsi_inflight *inflight; + + rcu_read_lock(); + inflight = rcu_dereference(vs->vs_inflight); + if (inflight) + atomic_inc(&inflight->count); + rcu_read_unlock(); + + return inflight; +} + +static void tcm_vhost_dec_inflight(struct vhost_scsi_inflight *inflight) +{ + /* + * Wakeup the waiter when all the requests issued before the flush + * operation are finished. + */ + if (inflight && !atomic_dec_return(&inflight->count)) + wake_up(&inflight->wait); +} + +static bool tcm_vhost_done_inflight(struct vhost_scsi_inflight *inflight) +{ + return atomic_read(&inflight->count) == 0; +} + static bool tcm_vhost_check_feature(struct vhost_scsi *vs, int feature) { bool ret = false; @@ -402,6 +454,7 @@ static int tcm_vhost_queue_tm_rsp(struct se_cmd *se_cmd) static void tcm_vhost_free_evt(struct vhost_scsi *vs, struct tcm_vhost_evt *evt) { mutex_lock(&vs->vs_events_lock); + tcm_vhost_dec_inflight(evt->inflight); vs->vs_events_nr--; kfree(evt); mutex_unlock(&vs->vs_events_lock); @@ -423,6 +476,7 @@ static struct tcm_vhost_evt *tcm_vhost_allocate_evt(struct vhost_scsi *vs, if (evt) { evt->event.event = event; evt->event.reason = reason; + evt->inflight = tcm_vhost_inc_inflight(vs); vs->vs_events_nr++; } mutex_unlock(&vs->vs_events_lock); @@ -445,6 +499,8 @@ static void vhost_scsi_free_cmd(struct tcm_vhost_cmd *tv_cmd) kfree(tv_cmd->tvc_sgl); } + tcm_vhost_dec_inflight(tv_cmd->inflight); + kfree(tv_cmd); } @@ -595,6 +651,7 @@ static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd( tv_cmd->tvc_data_direction = data_direction; tv_cmd->tvc_nexus = tv_nexus; tv_cmd->tvc_vhost = vs; + tv_cmd->inflight = tcm_vhost_inc_inflight(vs); return tv_cmd; } @@ -983,10 +1040,22 @@ static void vhost_scsi_flush_vq(struct vhost_scsi *vs, int index) static void vhost_scsi_flush(struct vhost_scsi *vs) { int i; + struct vhost_scsi_inflight *inflight; + + inflight = ACCESS_ONCE(vs->vs_inflight); + if (!tcm_vhost_alloc_inflight(vs)) + return; for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) vhost_scsi_flush_vq(vs, i); vhost_work_flush(&vs->dev, &vs->vs_completion_work); + vhost_work_flush(&vs->dev, &vs->vs_event_work); + + /* Wait until all requests issued before the flush to be finished */ + if (inflight) { + wait_event(inflight->wait, tcm_vhost_done_inflight(inflight)); + kfree(inflight); + } } /* @@ -1195,6 +1264,9 @@ static int vhost_scsi_open(struct inode *inode, struct file *f) s->vs_events_dropped = false; mutex_init(&s->vs_events_lock); + if (!tcm_vhost_alloc_inflight(s)) + return -ENOMEM; + s->vqs[VHOST_SCSI_VQ_CTL].handle_kick = vhost_scsi_ctl_handle_kick; s->vqs[VHOST_SCSI_VQ_EVT].handle_kick = vhost_scsi_evt_handle_kick; for (i = VHOST_SCSI_VQ_IO; i < VHOST_SCSI_MAX_VQ; i++) @@ -1220,6 +1292,7 @@ static int vhost_scsi_release(struct inode *inode, struct file *f) vhost_scsi_clear_endpoint(s, &t); vhost_dev_stop(&s->dev); vhost_dev_cleanup(&s->dev, false); + kfree(s->vs_inflight); kfree(s); return 0; } diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h index 94e9ee53..7567767 100644 --- a/drivers/vhost/tcm_vhost.h +++ b/drivers/vhost/tcm_vhost.h @@ -2,6 +2,7 @@ #define TCM_VHOST_NAMELEN 256 #define TCM_VHOST_MAX_CDB_SIZE 32 +struct vhost_scsi_inflight; struct tcm_vhost_cmd { /* Descriptor from vhost_get_vq_desc() for virt_queue segment */ int tvc_vq_desc; @@ -37,6 +38,8 @@ struct tcm_vhost_cmd { unsigned char tvc_sense_buf[TRANSPORT_SENSE_BUFFER]; /* Completed commands list, serviced from vhost worker thread */ struct llist_node tvc_completion_list; + /* Used to track inflight req */ + struct vhost_scsi_inflight *inflight; }; struct tcm_vhost_nexus { @@ -91,6 +94,8 @@ struct tcm_vhost_evt { struct virtio_scsi_event event; /* virtio_scsi event list, serviced from vhost worker thread */ struct llist_node list; + /* Used to track inflight req */ + struct vhost_scsi_inflight *inflight; }; /*