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virtio-blk: Unify {non-,}dataplane's request handlings

Browse Source 
This drops request handling code from dataplane, and uses code from
hw/block/virtio-blk.c.

It starts to use multiwrite as non-dataplane does.

Dataplane sets VirtIOBlock.complete_request to vring version, and calls
into non-dataplane's process handling. In complete_request_early,
qiov.size is added to vring push length, because it's also called in rw
completion now.

Signed-off-by: Fam Zheng <famz@redhat.com>
Tested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2014-06-17 14:32:09 +08:00 committed by Kevin Wolf
parent 4407c1c56a
commit b002254dbd
1 changed files with 19 additions and 164 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

183
hw/block/dataplane/virtio-blk.c
View File

@ -47,6 +47,8 @@ struct VirtIOBlockDataPlane {
/* Operation blocker on BDS */
Error *blocker;
void (*saved_complete_request)(struct VirtIOBlockReq *req,
unsigned char status);
};
/* Raise an interrupt to signal guest, if necessary */
@ -59,179 +61,27 @@ static void notify_guest(VirtIOBlockDataPlane *s)
event_notifier_set(s->guest_notifier);
}
static void complete_rdwr(void *opaque, int ret)
{
VirtIOBlockReq *req = opaque;
struct virtio_blk_inhdr hdr;
int len;
if (likely(ret == 0)) {
hdr.status = VIRTIO_BLK_S_OK;
len = req->qiov.size;
} else {
hdr.status = VIRTIO_BLK_S_IOERR;
len = 0;
}
trace_virtio_blk_data_plane_complete_request(req->dev->dataplane,
req->elem->index, ret);
stb_p(&req->in->status, hdr.status);
/* According to the virtio specification len should be the number of bytes
* written to, but for virtio-blk it seems to be the number of bytes
* transferred plus the status bytes.
*/
vring_push(&req->dev->dataplane->vring, req->elem, len + sizeof(hdr));
notify_guest(req->dev->dataplane);
g_slice_free(VirtIOBlockReq, req);
}
static void complete_request_early(VirtIOBlockReq *req, unsigned char status)
{
stb_p(&req->in->status, status);
vring_push(&req->dev->dataplane->vring, req->elem, sizeof(*req->in));
vring_push(&req->dev->dataplane->vring, req->elem,
req->qiov.size + sizeof(*req->in));
notify_guest(req->dev->dataplane);
g_slice_free(VirtIOBlockReq, req);
}
/* Get disk serial number */
static void do_get_id_cmd(VirtIOBlockReq *req,
struct iovec *iov, unsigned int iov_cnt)
{
char id[VIRTIO_BLK_ID_BYTES];
/* Serial number not NUL-terminated when longer than buffer */
strncpy(id, req->dev->blk.serial ? req->dev->blk.serial : "", sizeof(id));
iov_from_buf(iov, iov_cnt, 0, id, sizeof(id));
complete_request_early(req, VIRTIO_BLK_S_OK);
}
static void do_rdwr_cmd(bool read, VirtIOBlockReq *req,
struct iovec *iov, unsigned iov_cnt)
{
QEMUIOVector *qiov;
int nb_sectors;
int64_t sector_num;
qemu_iovec_init_external(&req->qiov, iov, iov_cnt);
qiov = &req->qiov;
sector_num = req->out.sector * 512 / BDRV_SECTOR_SIZE;
nb_sectors = qiov->size / BDRV_SECTOR_SIZE;
if (read) {
bdrv_aio_readv(req->dev->blk.conf.bs,
sector_num, qiov, nb_sectors,
complete_rdwr, req);
} else {
bdrv_aio_writev(req->dev->blk.conf.bs,
sector_num, qiov, nb_sectors,
complete_rdwr, req);
}
}
static void complete_flush(void *opaque, int ret)
{
VirtIOBlockReq *req = opaque;
unsigned char status;
if (ret == 0) {
status = VIRTIO_BLK_S_OK;
} else {
status = VIRTIO_BLK_S_IOERR;
}
complete_request_early(req, status);
}
static void do_flush_cmd(VirtIOBlockReq *req)
{
bdrv_aio_flush(req->dev->blk.conf.bs, complete_flush, req);
}
static void do_scsi_cmd(VirtIOBlockReq *req)
{
int status;
status = virtio_blk_handle_scsi_req(req->dev, req->elem);
complete_request_early(req, status);
}
static int process_request(VirtIOBlockDataPlane *s, VirtQueueElement *elem)
{
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;
VirtIOBlockReq *req;
req = g_slice_new(VirtIOBlockReq);
req->dev = VIRTIO_BLK(s->vdev);
req->elem = elem;
/* Copy in outhdr */
if (unlikely(iov_to_buf(iov, out_num, 0, &req->out,
sizeof(req->out)) != sizeof(req->out))) {
error_report("virtio-blk request outhdr too short");
g_slice_free(VirtIOBlockReq, req);
return -EFAULT;
}
iov_discard_front(&iov, &out_num, sizeof(req->out));
/* We are likely safe with the iov_len check, because inhdr is only 1 byte,
* but checking here in case the header gets bigger in the future. */
if (in_num < 1 || in_iov[in_num - 1].iov_len < sizeof(*req->in)) {
error_report("virtio-blk request inhdr too short");
return -EFAULT;
}
/* Grab inhdr for later */
req->in = (void *)in_iov[in_num - 1].iov_base
+ in_iov[in_num - 1].iov_len - sizeof(*req->in);
iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr));
/* TODO Linux sets the barrier bit even when not advertised! */
req->out.type &= ~VIRTIO_BLK_T_BARRIER;
switch (req->out.type) {
case VIRTIO_BLK_T_IN:
do_rdwr_cmd(true, req, in_iov, in_num);
return 0;
case VIRTIO_BLK_T_OUT:
do_rdwr_cmd(false, req, iov, out_num);
return 0;
case VIRTIO_BLK_T_SCSI_CMD:
do_scsi_cmd(req);
return 0;
case VIRTIO_BLK_T_FLUSH:
do_flush_cmd(req);
return 0;
case VIRTIO_BLK_T_GET_ID:
do_get_id_cmd(req, in_iov, in_num);
return 0;
default:
error_report("virtio-blk unsupported request type %#x", req->out.type);
g_slice_free(VirtIOBlockReq, req);
return -EFAULT;
}
}
static void handle_notify(EventNotifier *e)
{
VirtIOBlockDataPlane *s = container_of(e, VirtIOBlockDataPlane,
host_notifier);
VirtQueueElement *elem;
VirtIOBlockReq *req;
int ret;
MultiReqBuffer mrb = {
.num_writes = 0,
};
event_notifier_test_and_clear(&s->host_notifier);
for (;;) {
@ -248,14 +98,14 @@ static void handle_notify(EventNotifier *e)
trace_virtio_blk_data_plane_process_request(s, elem->out_num,
elem->in_num, elem->index);
if (process_request(s, elem) < 0) {
vring_set_broken(&s->vring);
vring_free_element(elem);
ret = -EFAULT;
break;
}
req = g_slice_new(VirtIOBlockReq);
req->dev = VIRTIO_BLK(s->vdev);
req->elem = elem;
virtio_blk_handle_request(req, &mrb);
}
virtio_submit_multiwrite(s->blk->conf.bs, &mrb);
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.
@ -275,6 +125,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
Error **errp)
{
VirtIOBlockDataPlane *s;
VirtIOBlock *vblk = VIRTIO_BLK(vdev);
Error *local_err = NULL;
*dataplane = NULL;
@ -317,6 +168,8 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
bdrv_op_block_all(blk->conf.bs, s->blocker);
*dataplane = s;
s->saved_complete_request = vblk->complete_request;
vblk->complete_request = complete_request_early;
}
/* Context: QEMU global mutex held */
@ -391,10 +244,12 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s->vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
if (!s->started || s->stopping) {
return;
}
s->stopping = true;
vblk->complete_request = s->saved_complete_request;
trace_virtio_blk_data_plane_stop(s);
aio_context_acquire(s->ctx);