[SCSI] qla2xxx: Properly handle UNDERRUN completion statuses.

Correct issues where the lower scsi-status would be improperly
cleared, instead, allow the midlayer to process the status after
the proper residual-count checks are performed.  Finally,
validate firmware status flags prior to assigning values from the
FCP_RSP frame.

Signed-off-by: Lalit Chandivade <lalit.chandivade@qlogic.com>
Signed-off-by: Michael Hernandez <michael.hernandez@qlogic.com>
Signed-off-by: Ravi Anand <ravi.anand@qlogic.com>
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 57 insertions, 63 deletions

diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index 4d758d29523c..804987397b77 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -1353,16 +1353,22 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
 
         sense_len = rsp_info_len = resid_len = fw_resid_len = 0;
         if (IS_FWI2_CAPABLE(ha)) {
-                sense_len = le32_to_cpu(sts24->sense_len);
-                rsp_info_len = le32_to_cpu(sts24->rsp_data_len);
-                resid_len = le32_to_cpu(sts24->rsp_residual_count);
-                fw_resid_len = le32_to_cpu(sts24->residual_len);
+                if (scsi_status & SS_SENSE_LEN_VALID)
+                        sense_len = le32_to_cpu(sts24->sense_len);
+                if (scsi_status & SS_RESPONSE_INFO_LEN_VALID)
+                        rsp_info_len = le32_to_cpu(sts24->rsp_data_len);
+                if (scsi_status & (SS_RESIDUAL_UNDER | SS_RESIDUAL_OVER))
+                        resid_len = le32_to_cpu(sts24->rsp_residual_count);
+                if (comp_status == CS_DATA_UNDERRUN)
+                        fw_resid_len = le32_to_cpu(sts24->residual_len);
                 rsp_info = sts24->data;
                 sense_data = sts24->data;
                 host_to_fcp_swap(sts24->data, sizeof(sts24->data));
         } else {
-                sense_len = le16_to_cpu(sts->req_sense_length);
-                rsp_info_len = le16_to_cpu(sts->rsp_info_len);
+                if (scsi_status & SS_SENSE_LEN_VALID)
+                        sense_len = le16_to_cpu(sts->req_sense_length);
+                if (scsi_status & SS_RESPONSE_INFO_LEN_VALID)
+                        rsp_info_len = le16_to_cpu(sts->rsp_info_len);
                 resid_len = le32_to_cpu(sts->residual_length);
                 rsp_info = sts->rsp_info;
                 sense_data = sts->req_sense_data;
@@ -1449,38 +1455,62 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
                 break;
 
         case CS_DATA_UNDERRUN:
-                resid = resid_len;
+                DEBUG2(printk(KERN_INFO
+                    "scsi(%ld:%d:%d) UNDERRUN status detected 0x%x-0x%x. "
+                    "resid=0x%x fw_resid=0x%x cdb=0x%x os_underflow=0x%x\n",
+                    vha->host_no, cp->device->id, cp->device->lun, comp_status,
+                    scsi_status, resid_len, fw_resid_len, cp->cmnd[0],
+                    cp->underflow));
+
                 /* Use F/W calculated residual length. */
-                if (IS_FWI2_CAPABLE(ha)) {
-                        if (!(scsi_status & SS_RESIDUAL_UNDER)) {
-                                lscsi_status = 0;
-                        } else if (resid != fw_resid_len) {
-                                scsi_status &= ~SS_RESIDUAL_UNDER;
-                                lscsi_status = 0;
+                resid = IS_FWI2_CAPABLE(ha) ? fw_resid_len : resid_len;
+                scsi_set_resid(cp, resid);
+                if (scsi_status & SS_RESIDUAL_UNDER) {
+                        if (IS_FWI2_CAPABLE(ha) && fw_resid_len != resid_len) {
+                                DEBUG2(printk(
+                                    "scsi(%ld:%d:%d:%d) Dropped frame(s) "
+                                    "detected (%x of %x bytes)...residual "
+                                    "length mismatch...retrying command.\n",
+                                    vha->host_no, cp->device->channel,
+                                    cp->device->id, cp->device->lun, resid,
+                                    scsi_bufflen(cp)));
+
+                                cp->result = DID_ERROR << 16 | lscsi_status;
+                                break;
                         }
-                        resid = fw_resid_len;
-                }
 
-                if (scsi_status & SS_RESIDUAL_UNDER) {
-                        scsi_set_resid(cp, resid);
-                } else {
-                        DEBUG2(printk(KERN_INFO
-                            "scsi(%ld:%d:%d) UNDERRUN status detected "
-                            "0x%x-0x%x. resid=0x%x fw_resid=0x%x cdb=0x%x "
-                            "os_underflow=0x%x\n", vha->host_no,
-                            cp->device->id, cp->device->lun, comp_status,
-                            scsi_status, resid_len, resid, cp->cmnd[0],
-                            cp->underflow));
+                        if (!lscsi_status &&
+                            ((unsigned)(scsi_bufflen(cp) - resid) <
+                            cp->underflow)) {
+                                qla_printk(KERN_INFO, ha,
+                                    "scsi(%ld:%d:%d:%d): Mid-layer underflow "
+                                    "detected (%x of %x bytes)...returning "
+                                    "error status.\n", vha->host_no,
+                                    cp->device->channel, cp->device->id,
+                                    cp->device->lun, resid, scsi_bufflen(cp));
 
+                                cp->result = DID_ERROR << 16;
+                                break;
+                        }
+                } else if (!lscsi_status) {
+                        DEBUG2(printk(
+                            "scsi(%ld:%d:%d:%d) Dropped frame(s) detected "
+                            "(%x of %x bytes)...firmware reported underrun..."
+                            "retrying command.\n", vha->host_no,
+                            cp->device->channel, cp->device->id,
+                            cp->device->lun, resid, scsi_bufflen(cp)));
+
+                        cp->result = DID_ERROR << 16;
+                        break;
                 }
 
+                cp->result = DID_OK << 16 | lscsi_status;
+
                 /*
                  * Check to see if SCSI Status is non zero. If so report SCSI
                  * Status.
                  */
                 if (lscsi_status != 0) {
-                        cp->result = DID_OK << 16 | lscsi_status;
-
                         if (lscsi_status == SAM_STAT_TASK_SET_FULL) {
                                 DEBUG2(printk(KERN_INFO
                                     "scsi(%ld): QUEUE FULL status detected "
@@ -1507,42 +1537,6 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
                                 break;
 
                         qla2x00_handle_sense(sp, sense_data, sense_len, rsp);
-                } else {
-                        /*
-                         * If RISC reports underrun and target does not report
-                         * it then we must have a lost frame, so tell upper
-                         * layer to retry it by reporting an error.
-                         */
-                        if (!(scsi_status & SS_RESIDUAL_UNDER)) {
-                                DEBUG2(printk("scsi(%ld:%d:%d:%d) Dropped "
-                                              "frame(s) detected (%x of %x bytes)..."
-                                              "retrying command.\n",
-                                        vha->host_no, cp->device->channel,
-                                        cp->device->id, cp->device->lun, resid,
-                                        scsi_bufflen(cp)));
-
-                                scsi_set_resid(cp, resid);
-                                cp->result = DID_ERROR << 16;
-                                break;
-                        }
-
-                        /* Handle mid-layer underflow */
-                        if ((unsigned)(scsi_bufflen(cp) - resid) <
-                            cp->underflow) {
-                                qla_printk(KERN_INFO, ha,
-                                           "scsi(%ld:%d:%d:%d): Mid-layer underflow "
-                                           "detected (%x of %x bytes)...returning "
-                                           "error status.\n", vha->host_no,
-                                           cp->device->channel, cp->device->id,
-                                           cp->device->lun, resid,
-                                           scsi_bufflen(cp));
-
-                                cp->result = DID_ERROR << 16;
-                                break;
-                        }
-
-                        /* Everybody online, looking good... */
-                        cp->result = DID_OK << 16;
                 }
                 break;