block/iscsi: set max_transfer_length

Copy the max_xfer_len from the BlockLimits VPD or use the
maximum value fitting in the CDB.

The helper function sector_limits_lun2qemu is introduced to convert
and cap the limits from the VPD to the maximum power of two fitting
in an integer; integer is the range for nb_sectors throughout
the block layer.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Peter Lieven 2014-10-27 10:18:45 +01:00 committed by Stefan Hajnoczi
parent 2647fab57d
commit 52f6fa1430

View File

@ -1447,12 +1447,25 @@ static void iscsi_close(BlockDriverState *bs)
memset(iscsilun, 0, sizeof(IscsiLun));
}
static int sector_limits_lun2qemu(int64_t sector, IscsiLun *iscsilun)
{
return MIN(sector_lun2qemu(sector, iscsilun), INT_MAX / 2 + 1);
}
static void iscsi_refresh_limits(BlockDriverState *bs, Error **errp)
{
IscsiLun *iscsilun = bs->opaque;
/* We don't actually refresh here, but just return data queried in
* iscsi_open(): iscsi targets don't change their limits. */
IscsiLun *iscsilun = bs->opaque;
uint32_t max_xfer_len = iscsilun->use_16_for_rw ? 0xffffffff : 0xffff;
if (iscsilun->bl.max_xfer_len) {
max_xfer_len = MIN(max_xfer_len, iscsilun->bl.max_xfer_len);
}
bs->bl.max_transfer_length = sector_limits_lun2qemu(max_xfer_len, iscsilun);
if (iscsilun->lbp.lbpu) {
if (iscsilun->bl.max_unmap < 0xffffffff) {
bs->bl.max_discard = sector_lun2qemu(iscsilun->bl.max_unmap,