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virtio-blk: Use blk_aio_ioctl 

Use the asynchronous interface of ioctl. This will not make the VM
unresponsive if the ioctl takes a long time.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2015-01-20 11:28:47 +08:00 committed by Kevin Wolf
parent 75344fa4c5
commit 1dc936aa84
1 changed files with 79 additions and 46 deletions
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125
hw/block/virtio-blk.c
View File

@ -115,6 +115,56 @@ static void virtio_blk_flush_complete(void *opaque, int ret)
virtio_blk_free_request(req);
}
#ifdef __linux__
typedef struct {
VirtIOBlockReq *req;
struct sg_io_hdr hdr;
} VirtIOBlockIoctlReq;
static void virtio_blk_ioctl_complete(void *opaque, int status)
{
VirtIOBlockIoctlReq *ioctl_req = opaque;
VirtIOBlockReq *req = ioctl_req->req;
VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
struct virtio_scsi_inhdr *scsi;
struct sg_io_hdr *hdr;
scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base;
if (status) {
status = VIRTIO_BLK_S_UNSUPP;
virtio_stl_p(vdev, &scsi->errors, 255);
goto out;
}
hdr = &ioctl_req->hdr;
/*
* From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)
* clear the masked_status field [hence status gets cleared too, see
* block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED
* status has occurred. However they do set DRIVER_SENSE in driver_status
* field. Also a (sb_len_wr > 0) indicates there is a sense buffer.
*/
if (hdr->status == 0 && hdr->sb_len_wr > 0) {
hdr->status = CHECK_CONDITION;
}
virtio_stl_p(vdev, &scsi->errors,
hdr->status | (hdr->msg_status << 8) |
(hdr->host_status << 16) | (hdr->driver_status << 24));
virtio_stl_p(vdev, &scsi->residual, hdr->resid);
virtio_stl_p(vdev, &scsi->sense_len, hdr->sb_len_wr);
virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len);
out:
virtio_blk_req_complete(req, status);
virtio_blk_free_request(req);
g_free(ioctl_req);
}
#endif
static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
{
VirtIOBlockReq *req = virtio_blk_alloc_request(s);
@ -137,7 +187,7 @@ static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req)
#ifdef __linux__
int i;
struct sg_io_hdr hdr;
VirtIOBlockIoctlReq *ioctl_req;
#endif
/*
@ -172,71 +222,52 @@ static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req)
}
#ifdef __linux__
memset(&hdr, 0, sizeof(struct sg_io_hdr));
hdr.interface_id = 'S';
hdr.cmd_len = elem->out_sg[1].iov_len;
hdr.cmdp = elem->out_sg[1].iov_base;
hdr.dxfer_len = 0;
ioctl_req = g_new0(VirtIOBlockIoctlReq, 1);
ioctl_req->req = req;
ioctl_req->hdr.interface_id = 'S';
ioctl_req->hdr.cmd_len = elem->out_sg[1].iov_len;
ioctl_req->hdr.cmdp = elem->out_sg[1].iov_base;
ioctl_req->hdr.dxfer_len = 0;
if (elem->out_num > 2) {
/*
* If there are more than the minimally required 2 output segments
* there is write payload starting from the third iovec.
*/
hdr.dxfer_direction = SG_DXFER_TO_DEV;
hdr.iovec_count = elem->out_num - 2;
ioctl_req->hdr.dxfer_direction = SG_DXFER_TO_DEV;
ioctl_req->hdr.iovec_count = elem->out_num - 2;
for (i = 0; i < hdr.iovec_count; i++)
hdr.dxfer_len += elem->out_sg[i + 2].iov_len;
for (i = 0; i < ioctl_req->hdr.iovec_count; i++) {
ioctl_req->hdr.dxfer_len += elem->out_sg[i + 2].iov_len;
}
hdr.dxferp = elem->out_sg + 2;
ioctl_req->hdr.dxferp = elem->out_sg + 2;
} else if (elem->in_num > 3) {
/*
* If we have more than 3 input segments the guest wants to actually
* read data.
*/
hdr.dxfer_direction = SG_DXFER_FROM_DEV;
hdr.iovec_count = elem->in_num - 3;
for (i = 0; i < hdr.iovec_count; i++)
hdr.dxfer_len += elem->in_sg[i].iov_len;
ioctl_req->hdr.dxfer_direction = SG_DXFER_FROM_DEV;
ioctl_req->hdr.iovec_count = elem->in_num - 3;
for (i = 0; i < ioctl_req->hdr.iovec_count; i++) {
ioctl_req->hdr.dxfer_len += elem->in_sg[i].iov_len;
}
hdr.dxferp = elem->in_sg;
ioctl_req->hdr.dxferp = elem->in_sg;
} else {
/*
* Some SCSI commands don't actually transfer any data.
*/
hdr.dxfer_direction = SG_DXFER_NONE;
ioctl_req->hdr.dxfer_direction = SG_DXFER_NONE;
}
hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base;
hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len;
ioctl_req->hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base;
ioctl_req->hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len;
status = blk_ioctl(blk->blk, SG_IO, &hdr);
if (status) {
status = VIRTIO_BLK_S_UNSUPP;
goto fail;
}
/*
* From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)
* clear the masked_status field [hence status gets cleared too, see
* block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED
* status has occurred. However they do set DRIVER_SENSE in driver_status
* field. Also a (sb_len_wr > 0) indicates there is a sense buffer.
*/
if (hdr.status == 0 && hdr.sb_len_wr > 0) {
hdr.status = CHECK_CONDITION;
}
virtio_stl_p(vdev, &scsi->errors,
hdr.status | (hdr.msg_status << 8) |
(hdr.host_status << 16) | (hdr.driver_status << 24));
virtio_stl_p(vdev, &scsi->residual, hdr.resid);
virtio_stl_p(vdev, &scsi->sense_len, hdr.sb_len_wr);
virtio_stl_p(vdev, &scsi->data_len, hdr.dxfer_len);
return status;
blk_aio_ioctl(blk->blk, SG_IO, &ioctl_req->hdr,
virtio_blk_ioctl_complete, ioctl_req);
return -EINPROGRESS;
#else
abort();
#endif
@ -254,8 +285,10 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
int status;
status = virtio_blk_handle_scsi_req(req);
virtio_blk_req_complete(req, status);
virtio_blk_free_request(req);
if (status != -EINPROGRESS) {
virtio_blk_req_complete(req, status);
virtio_blk_free_request(req);
}
}
void virtio_submit_multiwrite(BlockBackend *blk, MultiReqBuffer *mrb)