[SCSI] qla4xxx: Remove hiwat code so scsi eh does not get escalated when we can make progress

Removed unnecessary hiwat code to free up the number available IOCBs.
Eliminates unnecessary eh_ escalations due to inability to obtain IOCB
pkt for marker.

v2.
- Remove define not used anymore and fix req_q_coun accounting.

Signed-off-by: Karen Higgins <karen.higgins@qlogic.com>
[michaelc: ported patch from qlogic.com driver to upstream]
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

3 files changed, 60 insertions, 85 deletions

diff --git a/drivers/scsi/qla4xxx/ql4_def.h b/drivers/scsi/qla4xxx/ql4_def.h
index 963e8553d210..81b5f29254e2 100644
--- a/drivers/scsi/qla4xxx/ql4_def.h
+++ b/drivers/scsi/qla4xxx/ql4_def.h
@@ -100,7 +100,6 @@
 #define MAX_SRBS                MAX_CMDS_TO_RISC
 #define MBOX_AEN_REG_COUNT      5
 #define MAX_INIT_RETRIES        5
-#define IOCB_HIWAT_CUSHION      16
 
 /*
  * Buffer sizes
@@ -307,7 +306,6 @@ struct scsi_qla_host {
         uint32_t tot_ddbs;
 
         uint16_t        iocb_cnt;
-        uint16_t        iocb_hiwat;
 
         /* SRB cache. */
 #define SRB_MIN_REQ     128
diff --git a/drivers/scsi/qla4xxx/ql4_iocb.c b/drivers/scsi/qla4xxx/ql4_iocb.c
index 912a67494adf..e0c32159749c 100644
--- a/drivers/scsi/qla4xxx/ql4_iocb.c
+++ b/drivers/scsi/qla4xxx/ql4_iocb.c
@@ -10,9 +10,42 @@
 #include "ql4_dbg.h"
 #include "ql4_inline.h"
 
-
 #include <scsi/scsi_tcq.h>
 
+static int
+qla4xxx_space_in_req_ring(struct scsi_qla_host *ha, uint16_t req_cnt)
+{
+        uint16_t cnt;
+
+        /* Calculate number of free request entries. */
+        if ((req_cnt + 2) >= ha->req_q_count) {
+                cnt = (uint16_t) le32_to_cpu(ha->shadow_regs->req_q_out);
+                if (ha->request_in < cnt)
+                        ha->req_q_count = cnt - ha->request_in;
+                else
+                        ha->req_q_count = REQUEST_QUEUE_DEPTH -
+                                                (ha->request_in - cnt);
+        }
+
+        /* Check if room for request in request ring. */
+        if ((req_cnt + 2) < ha->req_q_count)
+                return 1;
+        else
+                return 0;
+}
+
+static void qla4xxx_advance_req_ring_ptr(struct scsi_qla_host *ha)
+{
+        /* Advance request queue pointer */
+        if (ha->request_in == (REQUEST_QUEUE_DEPTH - 1)) {
+                ha->request_in = 0;
+                ha->request_ptr = ha->request_ring;
+        } else {
+                ha->request_in++;
+                ha->request_ptr++;
+        }
+}
+
 /**
  * qla4xxx_get_req_pkt - returns a valid entry in request queue.
  * @ha: Pointer to host adapter structure.
@@ -26,35 +59,18 @@
 static int qla4xxx_get_req_pkt(struct scsi_qla_host *ha,
                                struct queue_entry **queue_entry)
 {
-        uint16_t request_in;
-        uint8_t status = QLA_SUCCESS;
-
-        *queue_entry = ha->request_ptr;
+        uint16_t req_cnt = 1;
 
-        /* get the latest request_in and request_out index */
-        request_in = ha->request_in;
-        ha->request_out = (uint16_t) le32_to_cpu(ha->shadow_regs->req_q_out);
-
-        /* Advance request queue pointer and check for queue full */
-        if (request_in == (REQUEST_QUEUE_DEPTH - 1)) {
-                request_in = 0;
-                ha->request_ptr = ha->request_ring;
-        } else {
-                request_in++;
-                ha->request_ptr++;
-        }
-
-        /* request queue is full, try again later */
-        if ((ha->iocb_cnt + 1) >= ha->iocb_hiwat) {
-                /* restore request pointer */
-                ha->request_ptr = *queue_entry;
-                status = QLA_ERROR;
-        } else {
-                ha->request_in = request_in;
+        if (qla4xxx_space_in_req_ring(ha, req_cnt)) {
+                *queue_entry = ha->request_ptr;
                 memset(*queue_entry, 0, sizeof(**queue_entry));
+
+                qla4xxx_advance_req_ring_ptr(ha);
+                ha->req_q_count -= req_cnt;
+                return QLA_SUCCESS;
         }
 
-        return status;
+        return QLA_ERROR;
 }
 
 /**
@@ -100,21 +116,14 @@ exit_send_marker:
         return status;
 }
 
-static struct continuation_t1_entry* qla4xxx_alloc_cont_entry(
-        struct scsi_qla_host *ha)
+static struct continuation_t1_entry *
+qla4xxx_alloc_cont_entry(struct scsi_qla_host *ha)
 {
         struct continuation_t1_entry *cont_entry;
 
         cont_entry = (struct continuation_t1_entry *)ha->request_ptr;
 
-        /* Advance request queue pointer */
-        if (ha->request_in == (REQUEST_QUEUE_DEPTH - 1)) {
-                ha->request_in = 0;
-                ha->request_ptr = ha->request_ring;
-        } else {
-                ha->request_in++;
-                ha->request_ptr++;
-        }
+        qla4xxx_advance_req_ring_ptr(ha);
 
         /* Load packet defaults */
         cont_entry->hdr.entryType = ET_CONTINUE;
@@ -197,13 +206,10 @@ int qla4xxx_send_command_to_isp(struct scsi_qla_host *ha, struct srb * srb)
         struct scsi_cmnd *cmd = srb->cmd;
         struct ddb_entry *ddb_entry;
         struct command_t3_entry *cmd_entry;
-
         int nseg;
         uint16_t tot_dsds;
         uint16_t req_cnt;
-
         unsigned long flags;
-        uint16_t cnt;
         uint32_t index;
         char tag[2];
 
@@ -217,6 +223,19 @@ int qla4xxx_send_command_to_isp(struct scsi_qla_host *ha, struct srb * srb)
 
         index = (uint32_t)cmd->request->tag;
 
+        /*
+         * Check to see if adapter is online before placing request on
+         * request queue.  If a reset occurs and a request is in the queue,
+         * the firmware will still attempt to process the request, retrieving
+         * garbage for pointers.
+         */
+        if (!test_bit(AF_ONLINE, &ha->flags)) {
+                DEBUG2(printk("scsi%ld: %s: Adapter OFFLINE! "
+                              "Do not issue command.\n",
+                              ha->host_no, __func__));
+                goto queuing_error;
+        }
+
         /* Calculate the number of request entries needed. */
         nseg = scsi_dma_map(cmd);
         if (nseg < 0)
@@ -224,17 +243,7 @@ int qla4xxx_send_command_to_isp(struct scsi_qla_host *ha, struct srb * srb)
         tot_dsds = nseg;
 
         req_cnt = qla4xxx_calc_request_entries(tot_dsds);
-
-        if (ha->req_q_count < (req_cnt + 2)) {
-                cnt = (uint16_t) le32_to_cpu(ha->shadow_regs->req_q_out);
-                if (ha->request_in < cnt)
-                        ha->req_q_count = cnt - ha->request_in;
-                else
-                        ha->req_q_count = REQUEST_QUEUE_DEPTH -
-                                (ha->request_in - cnt);
-        }
-
-        if (ha->req_q_count < (req_cnt + 2))
+        if (!qla4xxx_space_in_req_ring(ha, req_cnt))
                 goto queuing_error;
 
         /* total iocbs active */
@@ -286,32 +295,10 @@ int qla4xxx_send_command_to_isp(struct scsi_qla_host *ha, struct srb * srb)
                         break;
                 }
 
-
-        /* Advance request queue pointer */
-        ha->request_in++;
-        if (ha->request_in == REQUEST_QUEUE_DEPTH) {
-                ha->request_in = 0;
-                ha->request_ptr = ha->request_ring;
-        } else
-                ha->request_ptr++;
-
-
+        qla4xxx_advance_req_ring_ptr(ha);
         qla4xxx_build_scsi_iocbs(srb, cmd_entry, tot_dsds);
         wmb();
 
-        /*
-         * Check to see if adapter is online before placing request on
-         * request queue.  If a reset occurs and a request is in the queue,
-         * the firmware will still attempt to process the request, retrieving
-         * garbage for pointers.
-         */
-        if (!test_bit(AF_ONLINE, &ha->flags)) {
-                DEBUG2(printk("scsi%ld: %s: Adapter OFFLINE! "
-                              "Do not issue command.\n",
-                              ha->host_no, __func__));
-                goto queuing_error;
-        }
-
         srb->cmd->host_scribble = (unsigned char *)srb;
 
         /* update counters */
diff --git a/drivers/scsi/qla4xxx/ql4_mbx.c b/drivers/scsi/qla4xxx/ql4_mbx.c
index 051b0f5e8c8e..09d6d4b76f39 100644
--- a/drivers/scsi/qla4xxx/ql4_mbx.c
+++ b/drivers/scsi/qla4xxx/ql4_mbx.c
@@ -385,16 +385,6 @@ int qla4xxx_get_firmware_status(struct scsi_qla_host * ha)
                               mbox_sts[0]));
                 return QLA_ERROR;
         }
-
-        /* High-water mark of IOCBs */
-        ha->iocb_hiwat = mbox_sts[2];
-        if (ha->iocb_hiwat > IOCB_HIWAT_CUSHION)
-                ha->iocb_hiwat -= IOCB_HIWAT_CUSHION;
-        else
-                dev_info(&ha->pdev->dev, "WARNING!!!  You have less than %d "
-                           "firmware IOCBs available (%d).\n",
-                           IOCB_HIWAT_CUSHION, ha->iocb_hiwat);
-
         return QLA_SUCCESS;
 }