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Re: [Qemu-devel] [PATCH] iSCSI: Add support for SG_IO in bdrv_ioctl()
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] iSCSI: Add support for SG_IO in bdrv_ioctl() |
Date: |
Tue, 21 Aug 2012 09:00:15 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 |
Il 21/08/2012 01:59, Ronnie Sahlberg ha scritto:
> We need to support SG_IO in the synchronous bdrv_ioctl() since this
> is used by scsi-block
>
> Signed-off-by: Ronnie Sahlberg <address@hidden>
> ---
> block/iscsi.c | 109
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 108 insertions(+), 1 deletions(-)
>
> diff --git a/block/iscsi.c b/block/iscsi.c
> index 993a86d..9e98bfe 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -548,7 +548,8 @@ iscsi_aio_ioctl_cb(struct iscsi_context *iscsi, int
> status,
>
> #define SG_ERR_DRIVER_SENSE 0x08
>
> - if (status == SCSI_STATUS_CHECK_CONDITION && acb->task->datain.size >=
> 2) {
> + if (status == SCSI_STATUS_CHECK_CONDITION
> + && acb->task->datain.size >= 2) {
> int ss;
>
> acb->ioh->driver_status |= SG_ERR_DRIVER_SENSE;
> @@ -633,9 +634,53 @@ static BlockDriverAIOCB
> *iscsi_aio_ioctl(BlockDriverState *bs,
> return &acb->common;
> }
>
> +struct IoctlTask {
> + int status;
> + int complete;
> + sg_io_hdr_t *ioh;
> + struct scsi_task *task;
> +};
> +
> +static void
> +iscsi_ioctl_cb(struct iscsi_context *iscsi, int status,
> + void *command_data, void *opaque)
> +{
> + struct IoctlTask *itask = opaque;
> +
> + if (status < 0) {
> + error_report("Failed to ioctl(SG_IO) to iSCSI lun. %s",
> + iscsi_get_error(iscsi));
> + itask->status = -EIO;
> + }
> +
> + itask->ioh->driver_status = 0;
> + itask->ioh->host_status = 0;
> + itask->ioh->resid = 0;
> +
> +#define SG_ERR_DRIVER_SENSE 0x08
> +
> + if (status == SCSI_STATUS_CHECK_CONDITION
> + && itask->task->datain.size >= 2) {
> + int ss;
> +
> + itask->ioh->driver_status |= SG_ERR_DRIVER_SENSE;
> +
> + itask->ioh->sb_len_wr = itask->task->datain.size - 2;
> + ss = (itask->ioh->mx_sb_len >= itask->ioh->sb_len_wr) ?
> + itask->ioh->mx_sb_len : itask->ioh->sb_len_wr;
> + memcpy(itask->ioh->sbp, &itask->task->datain.data[2], ss);
> + }
> +
> + itask->complete = 1;
> +}
> +
> static int iscsi_ioctl(BlockDriverState *bs, unsigned long int req, void
> *buf)
> {
> IscsiLun *iscsilun = bs->opaque;
> + struct iscsi_context *iscsi = iscsilun->iscsi;
> + struct IoctlTask itask;
> + struct scsi_task *task;
> + struct iscsi_data data;
>
> switch (req) {
> case SG_GET_VERSION_NUM:
> @@ -644,6 +689,68 @@ static int iscsi_ioctl(BlockDriverState *bs, unsigned
> long int req, void *buf)
> case SG_GET_SCSI_ID:
> ((struct sg_scsi_id *)buf)->scsi_type = iscsilun->type;
> break;
> + case SG_IO:
> + itask.ioh = buf;
> + task = malloc(sizeof(struct scsi_task));
> + if (task == NULL) {
> + error_report("iSCSI: Failed to allocate task for scsi command.
> %s",
> + iscsi_get_error(iscsi));
> + return -1;
> + }
> + memset(task, 0, sizeof(struct scsi_task));
> +
> + switch (itask.ioh->dxfer_direction) {
> + case SG_DXFER_TO_DEV:
> + task->xfer_dir = SCSI_XFER_WRITE;
> + break;
> + case SG_DXFER_FROM_DEV:
> + task->xfer_dir = SCSI_XFER_READ;
> + break;
> + default:
> + task->xfer_dir = SCSI_XFER_NONE;
> + break;
> + }
> + task->cdb_size = itask.ioh->cmd_len;
> + memcpy(&task->cdb[0], itask.ioh->cmdp, itask.ioh->cmd_len);
> + task->expxferlen = itask.ioh->dxfer_len;
> +
> + if (task->xfer_dir == SCSI_XFER_WRITE) {
> + data.data = itask.ioh->dxferp;
> + data.size = itask.ioh->dxfer_len;
> + }
> +
> + if (iscsi_scsi_command_async(iscsi, iscsilun->lun, task,
> + iscsi_ioctl_cb,
> + (task->xfer_dir == SCSI_XFER_WRITE) ?
> + &data : NULL,
> + &itask) != 0) {
> + scsi_free_scsi_task(task);
> + return -1;
> + }
> +
> + /* tell libiscsi to read straight into the buffer we got from ioctl
> */
> + if (task->xfer_dir == SCSI_XFER_READ) {
> + scsi_task_add_data_in_buffer(task,
> + itask.ioh->dxfer_len,
> + itask.ioh->dxferp);
> + }
> +
> + itask.complete = 0;
> + itask.status = 0;
> + itask.task = task;
> + while (!itask.complete) {
> + iscsi_set_events(iscsilun);
> + qemu_aio_wait();
> + }
> + scsi_free_scsi_task(task);
> +
> + if (itask.status != 0) {
> + error_report("iSCSI: Failed to send async command to target :
> %s",
> + iscsi_get_error(iscsi));
> + return -1;
> + }
> +
> + return 0;
> default:
> return -1;
> }
>
Lots of duplicate code, can you just call bdrv_aio_ioctl with a callback
that is as simple as
int *p_status = opaque;
*p_status = status;
and then
status = -EINPROGRESS;
bdrv_aio_ioctl(..., ioctl_cb, &status);
while (status == -EINPROGRESS) {
qemu_aio_wait();
}
?
The iscsi_set_events should not be needed because bdrv_aio_ioctl calls it.
Paolo