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[109.64.41.91]) by smtp.gmail.com with ESMTPSA id q5sm3670947wrm.62.2020.06.02.06.06.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2020 06:06:21 -0700 (PDT) Date: Tue, 2 Jun 2020 09:06:20 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Eugenio =?utf-8?b?UMOpcmV6?= , Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, Paolo Bonzini , Stefan Hajnoczi Subject: [PATCH RFC 11/13] vhost/scsi: switch to buf APIs Message-ID: <20200602130543.578420-12-mst@redhat.com> References: <20200602130543.578420-1-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200602130543.578420-1-mst@redhat.com> X-Mailer: git-send-email 2.24.1.751.gd10ce2899c X-Mutt-Fcc: =sent Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Switch to buf APIs. Doing this exposes a spec violation in vhost scsi: all used bufs are marked with length 0. Fix that is left for another day. Signed-off-by: Michael S. Tsirkin Reviewed-by: Stefan Hajnoczi --- drivers/vhost/scsi.c | 73 ++++++++++++++++++++++++++------------------ 1 file changed, 44 insertions(+), 29 deletions(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index c39952243fd3..c426c4e899c7 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -71,8 +71,8 @@ struct vhost_scsi_inflight { }; struct vhost_scsi_cmd { - /* Descriptor from vhost_get_vq_desc() for virt_queue segment */ - int tvc_vq_desc; + /* Descriptor from vhost_get_avail_buf() for virt_queue segment */ + struct vhost_buf tvc_vq_desc; /* virtio-scsi initiator task attribute */ int tvc_task_attr; /* virtio-scsi response incoming iovecs */ @@ -213,7 +213,7 @@ struct vhost_scsi { * Context for processing request and control queue operations. */ struct vhost_scsi_ctx { - int head; + struct vhost_buf buf; unsigned int out, in; size_t req_size, rsp_size; size_t out_size, in_size; @@ -443,6 +443,20 @@ static int vhost_scsi_check_stop_free(struct se_cmd *se_cmd) return target_put_sess_cmd(se_cmd); } +/* Signal to guest that request finished with no input buffer. */ +/* TODO calling this when writing into buffer and most likely a bug */ +static void vhost_scsi_signal_noinput(struct vhost_dev *vdev, + struct vhost_virtqueue *vq, + struct vhost_buf *bufp) +{ + struct vhost_buf buf = *bufp; + + buf.in_len = 0; + vhost_put_used_buf(vq, &buf); + vhost_signal(vdev, vq); +} + + static void vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt) { @@ -450,7 +464,8 @@ vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt) struct virtio_scsi_event *event = &evt->event; struct virtio_scsi_event __user *eventp; unsigned out, in; - int head, ret; + struct vhost_buf buf; + int ret; if (!vhost_vq_get_backend(vq)) { vs->vs_events_missed = true; @@ -459,14 +474,14 @@ vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt) again: vhost_disable_notify(&vs->dev, vq); - head = vhost_get_vq_desc(vq, vq->iov, - ARRAY_SIZE(vq->iov), &out, &in, - NULL, NULL); - if (head < 0) { + ret = vhost_get_avail_buf(vq, &buf, + vq->iov, ARRAY_SIZE(vq->iov), &out, &in, + NULL, NULL); + if (ret < 0) { vs->vs_events_missed = true; return; } - if (head == vq->num) { + if (!ret) { if (vhost_enable_notify(&vs->dev, vq)) goto again; vs->vs_events_missed = true; @@ -488,7 +503,7 @@ vhost_scsi_do_evt_work(struct vhost_scsi *vs, struct vhost_scsi_evt *evt) eventp = vq->iov[out].iov_base; ret = __copy_to_user(eventp, event, sizeof(*event)); if (!ret) - vhost_add_used_and_signal(&vs->dev, vq, head, 0); + vhost_scsi_signal_noinput(&vs->dev, vq, &buf); else vq_err(vq, "Faulted on vhost_scsi_send_event\n"); } @@ -549,7 +564,7 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) ret = copy_to_iter(&v_rsp, sizeof(v_rsp), &iov_iter); if (likely(ret == sizeof(v_rsp))) { struct vhost_scsi_virtqueue *q; - vhost_add_used(cmd->tvc_vq, cmd->tvc_vq_desc, 0); + vhost_put_used_buf(cmd->tvc_vq, &cmd->tvc_vq_desc); q = container_of(cmd->tvc_vq, struct vhost_scsi_virtqueue, vq); vq = q - vs->vqs; __set_bit(vq, signal); @@ -793,7 +808,7 @@ static void vhost_scsi_submission_work(struct work_struct *work) static void vhost_scsi_send_bad_target(struct vhost_scsi *vs, struct vhost_virtqueue *vq, - int head, unsigned out) + struct vhost_buf *buf, unsigned out) { struct virtio_scsi_cmd_resp __user *resp; struct virtio_scsi_cmd_resp rsp; @@ -804,7 +819,7 @@ vhost_scsi_send_bad_target(struct vhost_scsi *vs, resp = vq->iov[out].iov_base; ret = __copy_to_user(resp, &rsp, sizeof(rsp)); if (!ret) - vhost_add_used_and_signal(&vs->dev, vq, head, 0); + vhost_scsi_signal_noinput(&vs->dev, vq, buf); else pr_err("Faulted on virtio_scsi_cmd_resp\n"); } @@ -813,21 +828,21 @@ static int vhost_scsi_get_desc(struct vhost_scsi *vs, struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc) { - int ret = -ENXIO; + int r, ret = -ENXIO; - vc->head = vhost_get_vq_desc(vq, vq->iov, - ARRAY_SIZE(vq->iov), &vc->out, &vc->in, - NULL, NULL); + r = vhost_get_avail_buf(vq, &vc->buf, + vq->iov, ARRAY_SIZE(vq->iov), &vc->out, &vc->in, + NULL, NULL); - pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n", - vc->head, vc->out, vc->in); + pr_debug("vhost_get_avail_buf: buf: %d, out: %u in: %u\n", + vc->buf.id, vc->out, vc->in); /* On error, stop handling until the next kick. */ - if (unlikely(vc->head < 0)) + if (unlikely(r < 0)) goto done; /* Nothing new? Wait for eventfd to tell us they refilled. */ - if (vc->head == vq->num) { + if (!r) { if (unlikely(vhost_enable_notify(&vs->dev, vq))) { vhost_disable_notify(&vs->dev, vq); ret = -EAGAIN; @@ -1093,11 +1108,11 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) } } /* - * Save the descriptor from vhost_get_vq_desc() to be used to + * Save the descriptor from vhost_get_avail_buf() to be used to * complete the virtio-scsi request in TCM callback context via * vhost_scsi_queue_data_in() and vhost_scsi_queue_status() */ - cmd->tvc_vq_desc = vc.head; + cmd->tvc_vq_desc = vc.buf; /* * Dispatch cmd descriptor for cmwq execution in process * context provided by vhost_scsi_workqueue. This also ensures @@ -1117,7 +1132,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) if (ret == -ENXIO) break; else if (ret == -EIO) - vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out); + vhost_scsi_send_bad_target(vs, vq, &vc.buf, vc.out); } while (likely(!vhost_exceeds_weight(vq, ++c, 0))); out: mutex_unlock(&vq->mutex); @@ -1139,9 +1154,9 @@ vhost_scsi_send_tmf_reject(struct vhost_scsi *vs, iov_iter_init(&iov_iter, READ, &vq->iov[vc->out], vc->in, sizeof(rsp)); ret = copy_to_iter(&rsp, sizeof(rsp), &iov_iter); - if (likely(ret == sizeof(rsp))) - vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0); - else + if (likely(ret == sizeof(rsp))) { + vhost_scsi_signal_noinput(&vs->dev, vq, &vc->buf); + } else pr_err("Faulted on virtio_scsi_ctrl_tmf_resp\n"); } @@ -1162,7 +1177,7 @@ vhost_scsi_send_an_resp(struct vhost_scsi *vs, ret = copy_to_iter(&rsp, sizeof(rsp), &iov_iter); if (likely(ret == sizeof(rsp))) - vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0); + vhost_scsi_signal_noinput(&vs->dev, vq, &vc->buf); else pr_err("Faulted on virtio_scsi_ctrl_an_resp\n"); } @@ -1269,7 +1284,7 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) if (ret == -ENXIO) break; else if (ret == -EIO) - vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out); + vhost_scsi_send_bad_target(vs, vq, &vc.buf, vc.out); } while (likely(!vhost_exceeds_weight(vq, ++c, 0))); out: mutex_unlock(&vq->mutex);