From: Matt Wang wwentao@vmware.com
[ Upstream commit e662502b3a782d479e67736a5a1c169a703d853a ]
Some commands (such as INQUIRY) may return less data than the initiator requested. To avoid conducting useless information, set the right residual count to make upper layer aware of this.
Before (INQUIRY PAGE 0xB0 with 128B buffer):
$ sg_raw -r 128 /dev/sda 12 01 B0 00 80 00 SCSI Status: Good
Received 128 bytes of data: 00 00 b0 00 3c 01 00 00 00 00 00 00 00 00 00 00 00 ...<............ 10 00 00 00 00 00 01 00 00 00 00 00 40 00 00 08 00 ...........@.... 20 80 00 00 00 00 00 00 00 00 00 20 00 00 00 00 00 .......... ..... 30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
After:
$ sg_raw -r 128 /dev/sda 12 01 B0 00 80 00 SCSI Status: Good
Received 64 bytes of data: 00 00 b0 00 3c 01 00 00 00 00 00 00 00 00 00 00 00 ...<............ 10 00 00 00 00 00 01 00 00 00 00 00 40 00 00 08 00 ...........@.... 20 80 00 00 00 00 00 00 00 00 00 20 00 00 00 00 00 .......... ..... 30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
[mkp: clarified description]
Link: https://lore.kernel.org/r/03C41093-B62E-43A2-913E-CFC92F1C70C3@vmware.com Signed-off-by: Matt Wang wwentao@vmware.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/vmw_pvscsi.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/vmw_pvscsi.c b/drivers/scsi/vmw_pvscsi.c index df6fabcce4f7..4d2172c115c6 100644 --- a/drivers/scsi/vmw_pvscsi.c +++ b/drivers/scsi/vmw_pvscsi.c @@ -577,7 +577,13 @@ static void pvscsi_complete_request(struct pvscsi_adapter *adapter, case BTSTAT_SUCCESS: case BTSTAT_LINKED_COMMAND_COMPLETED: case BTSTAT_LINKED_COMMAND_COMPLETED_WITH_FLAG: - /* If everything went fine, let's move on.. */ + /* + * 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. + */ + scsi_set_resid(cmd, scsi_bufflen(cmd) - e->dataLen); cmd->result = (DID_OK << 16); break;