On 10/28/19 3:57 AM, Damien Le Moal wrote:
struct scsi_cmnd cmd->req.resid_len which is returned and set
respectively by the helper functions scsi_get_resid() and
scsi_set_resid() is an unsigned int. Reflect this fact in the interface
of these helper functions.
[ ... ]
-static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
+static inline void scsi_set_resid(struct scsi_cmnd *cmd, unsigned int resid)
{
cmd->req.resid_len = resid;
}
-static inline int scsi_get_resid(struct scsi_cmnd *cmd)
+static inline unsigned int scsi_get_resid(struct scsi_cmnd *cmd)
{
return cmd->req.resid_len;
}
From the iSCSI RFC:
SCSI-Presented Data Transfer Length (SPDTL) is the term this document
uses (see Section 1.1 for definition) to represent the aggregate data
length that the target SCSI layer attempts to transfer using the
local iSCSI layer for a task. Expected Data Transfer Length (EDTL)
is the iSCSI term that represents the length of data that the iSCSI
layer expects to transfer for a task. EDTL is specified in the SCSI
Command PDU.
When SPDTL = EDTL for a task, the target iSCSI layer completes the
task with no residuals. Whenever SPDTL differs from EDTL for a task,
that task is said to have a residual.
If SPDTL > EDTL for a task, iSCSI Overflow MUST be signaled in the
SCSI Response PDU as specified in [RFC3720]. The Residual Count MUST
be set to the numerical value of (SPDTL - EDTL).
If SPDTL < EDTL for a task, iSCSI Underflow MUST be signaled in the
SCSI Response PDU as specified in [RFC3720]. The Residual Count MUST
be set to the numerical value of (EDTL - SPDTL).
Note that the Overflow and Underflow scenarios are independent of
Data-In and Data-Out. Either scenario is logically possible in
either direction of data transfer.
If the residual is changed from signed into unsigned, how is a SCSI LLD
expected to report the difference between residual overflow and residual
underflow to the SCSI core?
Thanks,
Bart.
