Re: [PATCH v1 1/3] scsi_cmnd: Introduce scsi_transfer_length helper

["Martin K. Petersen" <martin.petersen-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>]

>>>>> "Sagi" == Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> writes:

+static inline unsigned scsi_prot_length(unsigned data_length,
+					unsigned sector_size)
+{
+	switch (sector_size) {
+	case 512:
+		return (data_length >> 9) * 8;
+	case 1024:
+		return (data_length >> 10) * 8;
+	case 2048:
+		return (data_length >> 11) * 8;
+	case 4096:
+		return (data_length >> 12) * 8;
+	default:
+		return (data_length >> ilog2(sector_size)) * 8;
+	}
+}
+
+static inline unsigned scsi_transfer_length(struct scsi_cmnd *cmd)
+{
+	unsigned data_length;
+
+	if (cmd->sc_data_direction == DMA_FROM_DEVICE) {
+		data_length = scsi_in(cmd)->length;
+		if (scsi_get_prot_op(cmd) ==  SCSI_PROT_NORMAL ||
+		    scsi_get_prot_op(cmd) ==  SCSI_PROT_READ_INSERT)
+			return data_length;
+	} else {
+		data_length = scsi_out(cmd)->length;
+		if (scsi_get_prot_op(cmd) ==  SCSI_PROT_NORMAL ||
+		    scsi_get_prot_op(cmd) ==  SCSI_PROT_WRITE_STRIP)
+			return data_length;
+	}
+
+	/* Protection information exists on the wire */
+	return data_length + scsi_prot_length(data_length,
+					      cmd->device->sector_size);
+}

Let's do this for 3.16:

static inline unsigned int scsi_transfer_length(struct scsi_cmnd *scmd)
{
        unsigned int xfer_len = blk_rq_bytes(scmd->request);
        unsigned int prot_op = scsi_get_prot_op(scmd);

        switch (prot_op) {
        case SCSI_PROT_NORMAL:
        case SCSI_PROT_WRITE_STRIP:
        case SCSI_PROT_READ_INSERT:
             return xfer_len;
        }

        return xfer_len + (xfer_len >> ilog2(sector_size)) * 8;
}

And then in 3.17 we'll have:

static inline unsigned int scsi_transfer_length(struct scsi_cmnd *scmd)
{
        unsigned int xfer_len = blk_rq_bytes(scmd->request);
 
        if (scsi_prot_flagged(SCSI_PROT_TRANSFER_PI))
           xfer_len += (xfer_len >> ilog2(scsi_prot_interval(scmd))) * 8;

        return xfer_len;
}

-- 
Martin K. Petersen	Oracle Linux Engineering
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