pm80xx: NCQ error handling changes

Hello Sakthivel K,

This is a semi-automatic email about new static checker warnings.

The patch 1cde970c1025: "[SCSI] pm80xx: NCQ error handling changes" from Mar 19, 2013, leads to the following Smatch complaint:

drivers/scsi/pm8001/pm8001_hwi.c:4393 pm8001_chip_sata_req()
warn: variable dereferenced before check 'pm8001_ha_dev' (see line 4362)

drivers/scsi/pm8001/pm8001_hwi.c
4361 sata_cmd.tag = cpu_to_le32(tag);

  4362		sata_cmd.device_id = cpu_to_le32(pm8001_ha_dev->device_id);
                                                 ^^^^^^^^^^^^^

Old dereference.

4363 sata_cmd.data_len = cpu_to_le32(task->total_xfer_len);
4364 sata_cmd.ncqtag_atap_dir_m =
4365 cpu_to_le32(((ncg_tag & 0xff)<<16)|((ATAP & 0x3f) << 10) | dir);
4366 sata_cmd.sata_fis = task->ata_task.fis;
4367 if (likely(!task->ata_task.device_control_reg_update))
4368 sata_cmd.sata_fis.flags |= 0x80;/* C=1: update ATA cmd reg */
4369 sata_cmd.sata_fis.flags &= 0xF0;/* PM_PORT field shall be 0 */
4370 /* fill in PRD (scatter/gather) table, if any */
4371 if (task->num_scatter > 1) {
4372 pm8001_chip_make_sg(task->scatter, ccb->n_elem, ccb->buf_prd);
4373 phys_addr = ccb->ccb_dma_handle +
4374 offsetof(struct pm8001_ccb_info, buf_prd[0]);
4375 sata_cmd.addr_low = lower_32_bits(phys_addr);
4376 sata_cmd.addr_high = upper_32_bits(phys_addr);
4377 sata_cmd.esgl = cpu_to_le32(1 << 31);
4378 } else if (task->num_scatter == 1) {
4379 u64 dma_addr = sg_dma_address(task->scatter);
4380 sata_cmd.addr_low = lower_32_bits(dma_addr);
4381 sata_cmd.addr_high = upper_32_bits(dma_addr);
4382 sata_cmd.len = cpu_to_le32(task->total_xfer_len);
4383 sata_cmd.esgl = 0;
4384 } else if (task->num_scatter == 0) {
4385 sata_cmd.addr_low = 0;
4386 sata_cmd.addr_high = 0;
4387 sata_cmd.len = cpu_to_le32(task->total_xfer_len);
4388 sata_cmd.esgl = 0;
4389 }
4390
4391 /* Check for read log for failed drive and return */
4392 if (sata_cmd.sata_fis.command == 0x2f) {
4393 if (pm8001_ha_dev && ((pm8001_ha_dev->id & NCQ_READ_LOG_FLAG) ||

                            ^^^^^^^^^^^^^

New check. Probably this check is unneeded and can be removed.

  4394				(pm8001_ha_dev->id & NCQ_ABORT_ALL_FLAG) ||
  4395				(pm8001_ha_dev->id & NCQ_2ND_RLE_FLAG))) {

regards,
dan carpenter