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authorAlexey Makhalov <amakhalov@vmware.com>2021-12-20 11:05:14 -0800
committerMartin K. Petersen <martin.petersen@oracle.com>2021-12-22 23:17:27 -0500
commit142c779d05d1fef75134c3cb63f52ccbc96d9e1f (patch)
tree41ce85b080b383015bd2ff5dd5c9798b251ec5d3
parent1b8d0300a3e9f216ae4901bab886db7299899ec6 (diff)
scsi: vmw_pvscsi: Set residual data length conditionally
The PVSCSI implementation in the VMware hypervisor under specific configuration ("SCSI Bus Sharing" set to "Physical") returns zero dataLen in the completion descriptor for READ CAPACITY(16). As a result, the kernel can not detect proper disk geometry. This can be recognized by the kernel message: [ 0.776588] sd 1:0:0:0: [sdb] Sector size 0 reported, assuming 512. The PVSCSI implementation in QEMU does not set dataLen at all, keeping it zeroed. This leads to a boot hang as was reported by Shmulik Ladkani. It is likely that the controller returns the garbage at the end of the buffer. Residual length should be set by the driver in that case. The SCSI layer will erase corresponding data. See commit bdb2b8cab439 ("[SCSI] erase invalid data returned by device") for details. Commit e662502b3a78 ("scsi: vmw_pvscsi: Set correct residual data length") introduced the issue by setting residual length unconditionally, causing the SCSI layer to erase the useful payload beyond dataLen when this value is returned as 0. As a result, considering existing issues in implementations of PVSCSI controllers, we do not want to call scsi_set_resid() when dataLen == 0. Calling scsi_set_resid() has no effect if dataLen equals buffer length. Link: https://lore.kernel.org/lkml/20210824120028.30d9c071@blondie/ Link: https://lore.kernel.org/r/20211220190514.55935-1-amakhalov@vmware.com Fixes: e662502b3a78 ("scsi: vmw_pvscsi: Set correct residual data length") Cc: Matt Wang <wwentao@vmware.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Vishal Bhakta <vbhakta@vmware.com> Cc: VMware PV-Drivers <pv-drivers@vmware.com> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: linux-scsi@vger.kernel.org Cc: stable@vger.kernel.org Reported-and-suggested-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Signed-off-by: Alexey Makhalov <amakhalov@vmware.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
-rw-r--r--drivers/scsi/vmw_pvscsi.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/scsi/vmw_pvscsi.c b/drivers/scsi/vmw_pvscsi.c
index c2ba65224633..1f037b8ab904 100644
--- a/drivers/scsi/vmw_pvscsi.c
+++ b/drivers/scsi/vmw_pvscsi.c
@@ -586,9 +586,12 @@ static void pvscsi_complete_request(struct pvscsi_adapter *adapter,
* Commands like INQUIRY may transfer less data than
* requested by the initiator via bufflen. Set residual
* count to make upper layer aware of the actual amount
- * of data returned.
+ * of data returned. There are cases when controller
+ * returns zero dataLen with non zero data - do not set
+ * residual count in that case.
*/
- scsi_set_resid(cmd, scsi_bufflen(cmd) - e->dataLen);
+ if (e->dataLen && (e->dataLen < scsi_bufflen(cmd)))
+ scsi_set_resid(cmd, scsi_bufflen(cmd) - e->dataLen);
cmd->result = (DID_OK << 16);
break;