mvsas: ATAPI LUN issue

I found that sending REPORT_LUNS command to some DVD device will
cause fis error and controller error record. As a result, scsi mid layer get some wrong LUNs. Also I can get some queer messages.

scsi: host 12 channel 0 id 2 lun 0x30302e302f686f73 has a LUN larger than currently supported.
scsi: host 12 channel 0 id 2 lun 0x7431322f706f7274 has a LUN larger than currently supported.
scsi: host 12 channel 0 id 2 lun 0x2d31323a322f656e has a LUN larger than currently supported.
...

The patch forced to clear the sg buffer of SATA response if FIS is
error. But I suggest these codes should remove to the libsas module.

---
drivers/scsi/mvsas.c | 8 +++++++-

1 files changed, 7 insertions(+), 1 deletions(-)

index e55b903..42f3e90 100644
@@ -1263,8 +1263,14 @@ static int mvs_sata_done(struct mvs_info *mvi, struct sas_task *task,
           SATA_RECEIVED_D2H_FIS(port->taskfileset),
           sizeof(struct dev_to_host_fis));
    tstat->buf_valid_size = sizeof(*resp);
-    if (unlikely(err))
+    if (unlikely(err)) {
+        struct scatterlist *sg = task->scatter;
+        u8 *buf;
        stat = SAS_PROTO_RESPONSE;
+        buf = kmap_atomic(sg_page(sg), KM_IRQ0) + sg->offset;
+        memset(buf, 0, sg->length);
+        kunmap_atomic(buf - sg->offset, KM_IRQ0);
+    }
    return stat;

}

1.5.4

My first observation is that this isn't the correct approach: Most of the CD/DVD simply respond with an error or the correct information. The odd media changer will actually respond with real LUNs. Doing a blanket erase of the REPORT LUN information will cause problems for media changers.

I think the correct way to fix your problem is to blacklist the particular CD. We have a BLIST_NOREPORTLUN for devices which behave like this ... what are the INQUIRY strings?

James