From 3f8ca2e115e55af4c15d97dda635e948d2e380be Mon Sep 17 00:00:00 2001 From: Bijan Mottahedeh Date: Mon, 17 Sep 2018 17:09:48 -0700 Subject: vhost/scsi: Extract common handling code from control queue handler Prepare to change the request queue handler to use common handling routines. Signed-off-by: Bijan Mottahedeh Signed-off-by: Michael S. Tsirkin --- drivers/vhost/scsi.c | 271 ++++++++++++++++++++++++++++++++------------------- 1 file changed, 172 insertions(+), 99 deletions(-) (limited to 'drivers/vhost') diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 1c33d6e39152..4cd03a1d7f21 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -203,6 +203,19 @@ struct vhost_scsi { int vs_events_nr; /* num of pending events, protected by vq->mutex */ }; +/* + * Context for processing request and control queue operations. + */ +struct vhost_scsi_ctx { + int head; + unsigned int out, in; + size_t req_size, rsp_size; + size_t out_size, in_size; + u8 *target, *lunp; + void *req; + struct iov_iter out_iter; +}; + static struct workqueue_struct *vhost_scsi_workqueue; /* Global spinlock to protect vhost_scsi TPG list for vhost IOCTL access */ @@ -1050,10 +1063,107 @@ out: mutex_unlock(&vq->mutex); } +static int +vhost_scsi_get_desc(struct vhost_scsi *vs, struct vhost_virtqueue *vq, + struct vhost_scsi_ctx *vc) +{ + int ret = -ENXIO; + + vc->head = vhost_get_vq_desc(vq, 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); + + /* On error, stop handling until the next kick. */ + if (unlikely(vc->head < 0)) + goto done; + + /* Nothing new? Wait for eventfd to tell us they refilled. */ + if (vc->head == vq->num) { + if (unlikely(vhost_enable_notify(&vs->dev, vq))) { + vhost_disable_notify(&vs->dev, vq); + ret = -EAGAIN; + } + goto done; + } + + /* + * Get the size of request and response buffers. + */ + vc->out_size = iov_length(vq->iov, vc->out); + vc->in_size = iov_length(&vq->iov[vc->out], vc->in); + + /* + * Copy over the virtio-scsi request header, which for a + * ANY_LAYOUT enabled guest may span multiple iovecs, or a + * single iovec may contain both the header + outgoing + * WRITE payloads. + * + * copy_from_iter() will advance out_iter, so that it will + * point at the start of the outgoing WRITE payload, if + * DMA_TO_DEVICE is set. + */ + iov_iter_init(&vc->out_iter, WRITE, vq->iov, vc->out, vc->out_size); + ret = 0; + +done: + return ret; +} + +static int +vhost_scsi_chk_size(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc) +{ + if (unlikely(vc->in_size < vc->rsp_size)) { + vq_err(vq, + "Response buf too small, need min %zu bytes got %zu", + vc->rsp_size, vc->in_size); + return -EINVAL; + } else if (unlikely(vc->out_size < vc->req_size)) { + vq_err(vq, + "Request buf too small, need min %zu bytes got %zu", + vc->req_size, vc->out_size); + return -EIO; + } + + return 0; +} + +static int +vhost_scsi_get_req(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc, + struct vhost_scsi_tpg **tpgp) +{ + int ret = -EIO; + + if (unlikely(!copy_from_iter_full(vc->req, vc->req_size, + &vc->out_iter))) + vq_err(vq, "Faulted on copy_from_iter\n"); + else if (unlikely(*vc->lunp != 1)) + /* virtio-scsi spec requires byte 0 of the lun to be 1 */ + vq_err(vq, "Illegal virtio-scsi lun: %u\n", *vc->lunp); + else { + struct vhost_scsi_tpg **vs_tpg, *tpg; + + vs_tpg = vq->private_data; /* validated at handler entry */ + + tpg = READ_ONCE(vs_tpg[*vc->target]); + if (unlikely(!tpg)) + vq_err(vq, "Target 0x%x does not exist\n", *vc->target); + else { + if (tpgp) + *tpgp = tpg; + ret = 0; + } + } + + return ret; +} + static void vhost_scsi_send_tmf_resp(struct vhost_scsi *vs, - struct vhost_virtqueue *vq, - int head, unsigned int out) + struct vhost_virtqueue *vq, + struct vhost_scsi_ctx *vc) { struct virtio_scsi_ctrl_tmf_resp __user *resp; struct virtio_scsi_ctrl_tmf_resp rsp; @@ -1062,18 +1172,18 @@ vhost_scsi_send_tmf_resp(struct vhost_scsi *vs, pr_debug("%s\n", __func__); memset(&rsp, 0, sizeof(rsp)); rsp.response = VIRTIO_SCSI_S_FUNCTION_REJECTED; - resp = vq->iov[out].iov_base; + resp = vq->iov[vc->out].iov_base; ret = __copy_to_user(resp, &rsp, sizeof(rsp)); if (!ret) - vhost_add_used_and_signal(&vs->dev, vq, head, 0); + vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0); else pr_err("Faulted on virtio_scsi_ctrl_tmf_resp\n"); } static void vhost_scsi_send_an_resp(struct vhost_scsi *vs, - struct vhost_virtqueue *vq, - int head, unsigned int out) + struct vhost_virtqueue *vq, + struct vhost_scsi_ctx *vc) { struct virtio_scsi_ctrl_an_resp __user *resp; struct virtio_scsi_ctrl_an_resp rsp; @@ -1082,10 +1192,10 @@ vhost_scsi_send_an_resp(struct vhost_scsi *vs, pr_debug("%s\n", __func__); memset(&rsp, 0, sizeof(rsp)); /* event_actual = 0 */ rsp.response = VIRTIO_SCSI_S_OK; - resp = vq->iov[out].iov_base; + resp = vq->iov[vc->out].iov_base; ret = __copy_to_user(resp, &rsp, sizeof(rsp)); if (!ret) - vhost_add_used_and_signal(&vs->dev, vq, head, 0); + vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0); else pr_err("Faulted on virtio_scsi_ctrl_an_resp\n"); } @@ -1098,13 +1208,9 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) struct virtio_scsi_ctrl_an_req an; struct virtio_scsi_ctrl_tmf_req tmf; } v_req; - struct iov_iter out_iter; - unsigned int out = 0, in = 0; - int head; - size_t req_size, rsp_size, typ_size; - size_t out_size, in_size; - u8 *lunp; - void *req; + struct vhost_scsi_ctx vc; + size_t typ_size; + int ret; mutex_lock(&vq->mutex); /* @@ -1114,52 +1220,28 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) if (!vq->private_data) goto out; + memset(&vc, 0, sizeof(vc)); + vhost_disable_notify(&vs->dev, vq); for (;;) { - head = vhost_get_vq_desc(vq, vq->iov, - ARRAY_SIZE(vq->iov), &out, &in, - NULL, NULL); - pr_debug("vhost_get_vq_desc: head: %d, out: %u in: %u\n", - head, out, in); - /* On error, stop handling until the next kick. */ - if (unlikely(head < 0)) - break; - /* Nothing new? Wait for eventfd to tell us they refilled. */ - if (head == vq->num) { - if (unlikely(vhost_enable_notify(&vs->dev, vq))) { - vhost_disable_notify(&vs->dev, vq); - continue; - } - break; - } + ret = vhost_scsi_get_desc(vs, vq, &vc); + if (ret) + goto err; /* - * Get the size of request and response buffers. + * Get the request type first in order to setup + * other parameters dependent on the type. */ - out_size = iov_length(vq->iov, out); - in_size = iov_length(&vq->iov[out], in); - - /* - * Copy over the virtio-scsi request header, which for a - * ANY_LAYOUT enabled guest may span multiple iovecs, or a - * single iovec may contain both the header + outgoing - * WRITE payloads. - * - * copy_from_iter() will advance out_iter, so that it will - * point at the start of the outgoing WRITE payload, if - * DMA_TO_DEVICE is set. - */ - iov_iter_init(&out_iter, WRITE, vq->iov, out, out_size); - - req = &v_req.type; + vc.req = &v_req.type; typ_size = sizeof(v_req.type); - if (unlikely(!copy_from_iter_full(req, typ_size, &out_iter))) { + if (unlikely(!copy_from_iter_full(vc.req, typ_size, + &vc.out_iter))) { vq_err(vq, "Faulted on copy_from_iter tmf type\n"); /* - * The size of the response buffer varies based on - * the request type and must be validated against it. + * The size of the response buffer depends on the + * request type and must be validated against it. * Since the request type is not known, don't send * a response. */ @@ -1168,17 +1250,19 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) switch (v_req.type) { case VIRTIO_SCSI_T_TMF: - req = &v_req.tmf; - lunp = &v_req.tmf.lun[0]; - req_size = sizeof(struct virtio_scsi_ctrl_tmf_req); - rsp_size = sizeof(struct virtio_scsi_ctrl_tmf_resp); + vc.req = &v_req.tmf; + vc.req_size = sizeof(struct virtio_scsi_ctrl_tmf_req); + vc.rsp_size = sizeof(struct virtio_scsi_ctrl_tmf_resp); + vc.lunp = &v_req.tmf.lun[0]; + vc.target = &v_req.tmf.lun[1]; break; case VIRTIO_SCSI_T_AN_QUERY: case VIRTIO_SCSI_T_AN_SUBSCRIBE: - req = &v_req.an; - lunp = &v_req.an.lun[0]; - req_size = sizeof(struct virtio_scsi_ctrl_an_req); - rsp_size = sizeof(struct virtio_scsi_ctrl_an_resp); + vc.req = &v_req.an; + vc.req_size = sizeof(struct virtio_scsi_ctrl_an_req); + vc.rsp_size = sizeof(struct virtio_scsi_ctrl_an_resp); + vc.lunp = &v_req.an.lun[0]; + vc.target = NULL; break; default: vq_err(vq, "Unknown control request %d", v_req.type); @@ -1186,50 +1270,39 @@ vhost_scsi_ctl_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) } /* - * Check for a sane response buffer so we can report early - * errors back to the guest. + * Validate the size of request and response buffers. + * Check for a sane response buffer so we can report + * early errors back to the guest. */ - if (unlikely(in_size < rsp_size)) { - vq_err(vq, - "Resp buf too small, need min %zu bytes got %zu", - rsp_size, in_size); - /* - * Notifications are disabled at this point; - * continue so they can be eventually enabled - * when processing terminates. - */ - continue; - } + ret = vhost_scsi_chk_size(vq, &vc); + if (ret) + goto err; - if (unlikely(out_size < req_size)) { - vq_err(vq, - "Req buf too small, need min %zu bytes got %zu", - req_size, out_size); - vhost_scsi_send_bad_target(vs, vq, head, out); - continue; - } - - req += typ_size; - req_size -= typ_size; - - if (unlikely(!copy_from_iter_full(req, req_size, &out_iter))) { - vq_err(vq, "Faulted on copy_from_iter\n"); - vhost_scsi_send_bad_target(vs, vq, head, out); - continue; - } + /* + * Get the rest of the request now that its size is known. + */ + vc.req += typ_size; + vc.req_size -= typ_size; - /* virtio-scsi spec requires byte 0 of the lun to be 1 */ - if (unlikely(*lunp != 1)) { - vq_err(vq, "Illegal virtio-scsi lun: %u\n", *lunp); - vhost_scsi_send_bad_target(vs, vq, head, out); - continue; - } + ret = vhost_scsi_get_req(vq, &vc, NULL); + if (ret) + goto err; - if (v_req.type == VIRTIO_SCSI_T_TMF) { - pr_debug("%s tmf %d\n", __func__, v_req.tmf.subtype); - vhost_scsi_send_tmf_resp(vs, vq, head, out); - } else - vhost_scsi_send_an_resp(vs, vq, head, out); + if (v_req.type == VIRTIO_SCSI_T_TMF) + vhost_scsi_send_tmf_resp(vs, vq, &vc); + else + vhost_scsi_send_an_resp(vs, vq, &vc); +err: + /* + * ENXIO: No more requests, or read error, wait for next kick + * EINVAL: Invalid response buffer, drop the request + * EIO: Respond with bad target + * EAGAIN: Pending request + */ + if (ret == -ENXIO) + break; + else if (ret == -EIO) + vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out); } out: mutex_unlock(&vq->mutex); -- cgit v1.2.3-59-g8ed1b