Re: [Qemu-devel] [PATCHv5 3/3] iscsi: add .bdrv_co_discard

[Peter Lieven]

On 19.07.2013 11:18, Paolo Bonzini wrote:
> Il 19/07/2013 09:19, Peter Lieven ha scritto:
> > Signed-off-by: Peter Lieven <address@hidden>
> > ---
> >   block/iscsi.c |  156 +++++++++++++++++++++++++++------------------------------
> >   1 file changed, 73 insertions(+), 83 deletions(-)
> >
> > diff --git a/block/iscsi.c b/block/iscsi.c
> > index 19afd6c..cb44fb1 100644
> > --- a/block/iscsi.c
> > +++ b/block/iscsi.c
> > @@ -85,6 +85,7 @@ typedef struct IscsiAIOCB {
> >   #define NOP_INTERVAL 5000
> >   #define MAX_NOP_FAILURES 3
> >   #define ISCSI_CMD_RETRIES 5
> > +#define ISCSI_MAX_UNMAP 131072
> >   
> >   static void
> >   iscsi_bh_cb(void *p)
> > @@ -622,88 +623,6 @@ iscsi_aio_flush(BlockDriverState *bs,
> >       return &acb->common;
> >   }
> >   
> > -static int iscsi_aio_discard_acb(IscsiAIOCB *acb);
> > -
> > -static void
> > -iscsi_unmap_cb(struct iscsi_context *iscsi, int status,
> > -                     void *command_data, void *opaque)
> > -{
> > -    IscsiAIOCB *acb = opaque;
> > -
> > -    if (acb->canceled != 0) {
> > -        return;
> > -    }
> > -
> > -    acb->status = 0;
> > -    if (status != 0) {
> > -        if (status == SCSI_STATUS_CHECK_CONDITION
> > -            && acb->task->sense.key == SCSI_SENSE_UNIT_ATTENTION
> > -            && acb->retries-- > 0) {
> > -            scsi_free_scsi_task(acb->task);
> > -            acb->task = NULL;
> > -            if (iscsi_aio_discard_acb(acb) == 0) {
> > -                iscsi_set_events(acb->iscsilun);
> > -                return;
> > -            }
> > -        }
> > -        error_report("Failed to unmap data on iSCSI lun. %s",
> > -                     iscsi_get_error(iscsi));
> > -        acb->status = -EIO;
> > -    }
> > -
> > -    iscsi_schedule_bh(acb);
> > -}
> > -
> > -static int iscsi_aio_discard_acb(IscsiAIOCB *acb) {
> > -    struct iscsi_context *iscsi = acb->iscsilun->iscsi;
> > -    struct unmap_list list[1];
> > -
> > -    acb->canceled   = 0;
> > -    acb->bh         = NULL;
> > -    acb->status     = -EINPROGRESS;
> > -    acb->buf        = NULL;
> > -
> > -    list[0].lba = sector_qemu2lun(acb->sector_num, acb->iscsilun);
> > -    list[0].num = acb->nb_sectors * BDRV_SECTOR_SIZE / 
> > acb->iscsilun->block_size;
> > -
> > -    acb->task = iscsi_unmap_task(iscsi, acb->iscsilun->lun,
> > -                                 0, 0, &list[0], 1,
> > -                                 iscsi_unmap_cb,
> > -                                 acb);
> > -    if (acb->task == NULL) {
> > -        error_report("iSCSI: Failed to send unmap command. %s",
> > -                     iscsi_get_error(iscsi));
> > -        return -1;
> > -    }
> > -
> > -    return 0;
> > -}
> > -
> > -static BlockDriverAIOCB *
> > -iscsi_aio_discard(BlockDriverState *bs,
> > -                  int64_t sector_num, int nb_sectors,
> > -                  BlockDriverCompletionFunc *cb, void *opaque)
> > -{
> > -    IscsiLun *iscsilun = bs->opaque;
> > -    IscsiAIOCB *acb;
> > -
> > -    acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
> > -
> > -    acb->iscsilun    = iscsilun;
> > -    acb->nb_sectors  = nb_sectors;
> > -    acb->sector_num  = sector_num;
> > -    acb->retries     = ISCSI_CMD_RETRIES;
> > -
> > -    if (iscsi_aio_discard_acb(acb) != 0) {
> > -        qemu_aio_release(acb);
> > -        return NULL;
> > -    }
> > -
> > -    iscsi_set_events(iscsilun);
> > -
> > -    return &acb->common;
> > -}
> > -
> >   #ifdef __linux__
> >   static void
> >   iscsi_aio_ioctl_cb(struct iscsi_context *iscsi, int status,
> > @@ -985,6 +904,77 @@ out:
> >       return ret;
> >   }
> >   
> > +static int
> > +coroutine_fn iscsi_co_discard(BlockDriverState *bs, int64_t sector_num,
> > +                                   int nb_sectors)
> > +{
> > +    IscsiLun *iscsilun = bs->opaque;
> > +    struct IscsiTask iTask;
> > +    struct unmap_list list;
> > +    uint32_t nb_blocks;
> > +    uint32_t max_unmap;
> > +
> > +    if (!is_request_lun_aligned(sector_num, nb_sectors, iscsilun)) {
> > +        return -EINVAL;
> > +    }
> > +
> > +    if (!iscsilun->lbp.lbpu) {
> > +        /* UNMAP is not supported by the target */
> > +        return 0;
> > +    }
> I guess you'll later add support for lbpws.
It depends: I think almost all targets will support both. I would use unmap for 
discard and write_same for write_zeroes.

Peter
> Anyway, series looks fine.
Thanks. Feel free to pull it once the get_lba_status thing is upstream.

Peter