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

[Martin K. Petersen]

>>>>> "Sagi" == Sagi Grimberg <sa...@mellanox.com> 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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