Hello Johannes Thumshirn,
The patch 68c59fcea1f2: "scsi: sg: fix SG_DXFER_FROM_DEV transfers"
from Jul 7, 2017, leads to the following static checker warning:
drivers/scsi/sg.c:762 sg_is_valid_dxfer()
warn: unsigned 'hp->dxfer_len' is never less than zero.
drivers/scsi/sg.c
754 static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
755 {
756 switch (hp->dxfer_direction) {
757 case SG_DXFER_NONE:
758 if (hp->dxferp || hp->dxfer_len > 0)
759 return false;
760 return true;
761 case SG_DXFER_FROM_DEV:
762 if (hp->dxfer_len < 0)
^^^^^^^^^^^^^^^^^
Not possible.
763 return false;
764 return true;
765 case SG_DXFER_TO_DEV:
766 case SG_DXFER_TO_FROM_DEV:
767 if (!hp->dxferp || hp->dxfer_len == 0)
768 return false;
769 return true;
770 case SG_DXFER_UNKNOWN:
771 if ((!hp->dxferp && hp->dxfer_len) ||
772 (hp->dxferp && hp->dxfer_len == 0))
773 return false;
774 return true;
775 default:
776 return false;
777 }
778 }
Btw, I was looking up the type of hp->dxfer_len and I noticed that the
documentation for hp->resid is wrong. It says:
int resid; /* [o] dxfer_len - actual_transferred */
My guess is that resid stands for Response ID but I'm not positive.
regards,
dan carpenter
