From 781c117f3758bdb21e982d2aebba81febceccfe5 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 10 Dec 2013 13:26:59 +0100 Subject: vring: factor common code for error exits Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- hw/block/dataplane/virtio-blk.c | 1 + 1 file changed, 1 insertion(+) (limited to 'hw/block') diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index 1e57f3aabd..2b4a773f13 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -308,6 +308,7 @@ static void handle_notify(EventNotifier *e) if (process_request(&s->ioqueue, iov, out_num, in_num, head) < 0) { vring_set_broken(&s->vring); + ret = -EFAULT; break; } iov += out_num + in_num; -- cgit v1.2.1 From 8c1b566fd165af6cb12d6ef69eb554a347641e20 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 10 Dec 2013 13:27:00 +0100 Subject: dataplane: change vring API to use VirtQueueElement Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- hw/block/dataplane/virtio-blk.c | 85 ++++++++++++++++------------------------- 1 file changed, 33 insertions(+), 52 deletions(-) (limited to 'hw/block') diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index 2b4a773f13..456d437ac3 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -35,7 +35,7 @@ enum { typedef struct { struct iocb iocb; /* Linux AIO control block */ QEMUIOVector *inhdr; /* iovecs for virtio_blk_inhdr */ - unsigned int head; /* vring descriptor index */ + VirtQueueElement *elem; /* saved data from the virtqueue */ struct iovec *bounce_iov; /* used if guest buffers are unaligned */ QEMUIOVector *read_qiov; /* for read completion /w bounce buffer */ } VirtIOBlockRequest; @@ -96,7 +96,7 @@ static void complete_request(struct iocb *iocb, ssize_t ret, void *opaque) len = 0; } - trace_virtio_blk_data_plane_complete_request(s, req->head, ret); + trace_virtio_blk_data_plane_complete_request(s, req->elem->index, ret); if (req->read_qiov) { assert(req->bounce_iov); @@ -118,12 +118,12 @@ static void complete_request(struct iocb *iocb, ssize_t ret, void *opaque) * written to, but for virtio-blk it seems to be the number of bytes * transferred plus the status bytes. */ - vring_push(&s->vring, req->head, len + sizeof(hdr)); - + vring_push(&s->vring, req->elem, len + sizeof(hdr)); + req->elem = NULL; s->num_reqs--; } -static void complete_request_early(VirtIOBlockDataPlane *s, unsigned int head, +static void complete_request_early(VirtIOBlockDataPlane *s, VirtQueueElement *elem, QEMUIOVector *inhdr, unsigned char status) { struct virtio_blk_inhdr hdr = { @@ -134,26 +134,26 @@ static void complete_request_early(VirtIOBlockDataPlane *s, unsigned int head, qemu_iovec_destroy(inhdr); g_slice_free(QEMUIOVector, inhdr); - vring_push(&s->vring, head, sizeof(hdr)); + vring_push(&s->vring, elem, sizeof(hdr)); notify_guest(s); } /* Get disk serial number */ static void do_get_id_cmd(VirtIOBlockDataPlane *s, struct iovec *iov, unsigned int iov_cnt, - unsigned int head, QEMUIOVector *inhdr) + VirtQueueElement *elem, QEMUIOVector *inhdr) { char id[VIRTIO_BLK_ID_BYTES]; /* Serial number not NUL-terminated when shorter than buffer */ strncpy(id, s->blk->serial ? s->blk->serial : "", sizeof(id)); iov_from_buf(iov, iov_cnt, 0, id, sizeof(id)); - complete_request_early(s, head, inhdr, VIRTIO_BLK_S_OK); + complete_request_early(s, elem, inhdr, VIRTIO_BLK_S_OK); } static int do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read, - struct iovec *iov, unsigned int iov_cnt, - long long offset, unsigned int head, + struct iovec *iov, unsigned iov_cnt, + long long offset, VirtQueueElement *elem, QEMUIOVector *inhdr) { struct iocb *iocb; @@ -186,19 +186,20 @@ static int do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read, /* Fill in virtio block metadata needed for completion */ VirtIOBlockRequest *req = container_of(iocb, VirtIOBlockRequest, iocb); - req->head = head; + req->elem = elem; req->inhdr = inhdr; req->bounce_iov = bounce_iov; req->read_qiov = read_qiov; return 0; } -static int process_request(IOQueue *ioq, struct iovec iov[], - unsigned int out_num, unsigned int in_num, - unsigned int head) +static int process_request(IOQueue *ioq, VirtQueueElement *elem) { VirtIOBlockDataPlane *s = container_of(ioq, VirtIOBlockDataPlane, ioqueue); - struct iovec *in_iov = &iov[out_num]; + struct iovec *iov = elem->out_sg; + struct iovec *in_iov = elem->in_sg; + unsigned out_num = elem->out_num; + unsigned in_num = elem->in_num; struct virtio_blk_outhdr outhdr; QEMUIOVector *inhdr; size_t in_size; @@ -229,29 +230,29 @@ static int process_request(IOQueue *ioq, struct iovec iov[], switch (outhdr.type) { case VIRTIO_BLK_T_IN: - do_rdwr_cmd(s, true, in_iov, in_num, outhdr.sector * 512, head, inhdr); + do_rdwr_cmd(s, true, in_iov, in_num, outhdr.sector * 512, elem, inhdr); return 0; case VIRTIO_BLK_T_OUT: - do_rdwr_cmd(s, false, iov, out_num, outhdr.sector * 512, head, inhdr); + do_rdwr_cmd(s, false, iov, out_num, outhdr.sector * 512, elem, inhdr); return 0; case VIRTIO_BLK_T_SCSI_CMD: /* TODO support SCSI commands */ - complete_request_early(s, head, inhdr, VIRTIO_BLK_S_UNSUPP); + complete_request_early(s, elem, inhdr, VIRTIO_BLK_S_UNSUPP); return 0; case VIRTIO_BLK_T_FLUSH: /* TODO fdsync not supported by Linux AIO, do it synchronously here! */ if (qemu_fdatasync(s->fd) < 0) { - complete_request_early(s, head, inhdr, VIRTIO_BLK_S_IOERR); + complete_request_early(s, elem, inhdr, VIRTIO_BLK_S_IOERR); } else { - complete_request_early(s, head, inhdr, VIRTIO_BLK_S_OK); + complete_request_early(s, elem, inhdr, VIRTIO_BLK_S_OK); } return 0; case VIRTIO_BLK_T_GET_ID: - do_get_id_cmd(s, in_iov, in_num, head, inhdr); + do_get_id_cmd(s, in_iov, in_num, elem, inhdr); return 0; default: @@ -267,29 +268,8 @@ static void handle_notify(EventNotifier *e) VirtIOBlockDataPlane *s = container_of(e, VirtIOBlockDataPlane, host_notifier); - /* There is one array of iovecs into which all new requests are extracted - * from the vring. Requests are read from the vring and the translated - * descriptors are written to the iovecs array. The iovecs do not have to - * persist across handle_notify() calls because the kernel copies the - * iovecs on io_submit(). - * - * Handling io_submit() EAGAIN may require storing the requests across - * handle_notify() calls until the kernel has sufficient resources to - * accept more I/O. This is not implemented yet. - */ - struct iovec iovec[VRING_MAX]; - struct iovec *end = &iovec[VRING_MAX]; - struct iovec *iov = iovec; - - /* When a request is read from the vring, the index of the first descriptor - * (aka head) is returned so that the completed request can be pushed onto - * the vring later. - * - * The number of hypervisor read-only iovecs is out_num. The number of - * hypervisor write-only iovecs is in_num. - */ - int head; - unsigned int out_num = 0, in_num = 0; + VirtQueueElement *elem; + int ret; unsigned int num_queued; event_notifier_test_and_clear(&s->host_notifier); @@ -298,30 +278,31 @@ static void handle_notify(EventNotifier *e) vring_disable_notification(s->vdev, &s->vring); for (;;) { - head = vring_pop(s->vdev, &s->vring, iov, end, &out_num, &in_num); - if (head < 0) { + ret = vring_pop(s->vdev, &s->vring, &elem); + if (ret < 0) { + assert(elem == NULL); break; /* no more requests */ } - trace_virtio_blk_data_plane_process_request(s, out_num, in_num, - head); + trace_virtio_blk_data_plane_process_request(s, elem->out_num, + elem->in_num, elem->index); - if (process_request(&s->ioqueue, iov, out_num, in_num, head) < 0) { + if (process_request(&s->ioqueue, elem) < 0) { vring_set_broken(&s->vring); + vring_free_element(elem); ret = -EFAULT; break; } - iov += out_num + in_num; } - if (likely(head == -EAGAIN)) { /* vring emptied */ + if (likely(ret == -EAGAIN)) { /* vring emptied */ /* Re-enable guest->host notifies and stop processing the vring. * But if the guest has snuck in more descriptors, keep processing. */ if (vring_enable_notification(s->vdev, &s->vring)) { break; } - } else { /* head == -ENOBUFS or fatal error, iovecs[] is depleted */ + } else { /* ret == -ENOBUFS or fatal error, iovecs[] is depleted */ /* Since there are no iovecs[] left, stop processing for now. Do * not re-enable guest->host notifies since the I/O completion * handler knows to check for more vring descriptors anyway. -- cgit v1.2.1