[Qemu-devel] [PATCHv5 3/6] block/iscsi: set max_transfer_length

[Peter Lieven <pl@kamp.de>]

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

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/iscsi.c |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 233f462..1ae4add 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -297,6 +297,11 @@ static int64_t sector_lun2qemu(int64_t sector, IscsiLun *iscsilun)
     return sector * iscsilun->block_size / BDRV_SECTOR_SIZE;
 }
 
+static int nb_sectors_lun2qemu(int64_t sector, IscsiLun *iscsilun)
+{
+    return MIN(sector_lun2qemu(sector, iscsilun), INT_MAX);
+}
+
 static int64_t sector_qemu2lun(int64_t sector, IscsiLun *iscsilun)
 {
     return sector * BDRV_SECTOR_SIZE / iscsilun->block_size;
@@ -1449,10 +1454,18 @@ static void iscsi_close(BlockDriverState *bs)
 
 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 = nb_sectors_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,
-- 
1.7.9.5