snic: Fix for missing interrupts

- On posting an IO to the firmware, adapter generates an interrupt.
  Due to hardware issues, sometimes the adapter fails to generate
  the interrupt. This behavior skips updating transmit queue-
  counters, which in turn causes the queue full condition. The fix
  addresses the queue full condition.

- The fix also reserves a slot in transmit queue for hba reset.
  when queue full is observed during IO, there will always be room
  to post hba reset command.

Signed-off-by: Narsimhulu Musini <nmusini@cisco.com>
Signed-off-by: Sesidhar Baddela <sebaddel@cisco.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/snic/snic_fwint.h b/drivers/scsi/snic/snic_fwint.h
index 2cfaf2d..c5f9e19 100644 (file)
--- a/drivers/scsi/snic/snic_fwint.h
+++ b/drivers/scsi/snic/snic_fwint.h
@@ -414,7 +414,7 @@ enum snic_ev_type {
 /* Payload 88 bytes = 128 - 24 - 16 */
 #define SNIC_HOST_REQ_PAYLOAD  ((int)(SNIC_HOST_REQ_LEN -              \
                                        sizeof(struct snic_io_hdr) -    \
-                                       (2 * sizeof(u64))))
+                                       (2 * sizeof(u64)) - sizeof(ulong)))
 
 /*
  * snic_host_req: host -> firmware request
@@ -448,6 +448,8 @@ struct snic_host_req {
                /* hba reset */
                struct snic_hba_reset           reset;
        } u;
+
+       ulong req_pa;
 }; /* end of snic_host_req structure */
 
 

diff --git a/drivers/scsi/snic/snic_io.c b/drivers/scsi/snic/snic_io.c
index 993db7d..8e69548 100644 (file)
--- a/drivers/scsi/snic/snic_io.c
+++ b/drivers/scsi/snic/snic_io.c
@@ -48,7 +48,7 @@ snic_wq_cmpl_frame_send(struct vnic_wq *wq,
        SNIC_TRC(snic->shost->host_no, 0, 0,
                 ((ulong)(buf->os_buf) - sizeof(struct snic_req_info)), 0, 0,
                 0);
-       pci_unmap_single(snic->pdev, buf->dma_addr, buf->len, PCI_DMA_TODEVICE);
+
        buf->os_buf = NULL;
 }
 
@@ -137,13 +137,36 @@ snic_select_wq(struct snic *snic)
        return 0;
 }
 
+static int
+snic_wqdesc_avail(struct snic *snic, int q_num, int req_type)
+{
+       int nr_wqdesc = snic->config.wq_enet_desc_count;
+
+       if (q_num > 0) {
+               /*
+                * Multi Queue case, additional care is required.
+                * Per WQ active requests need to be maintained.
+                */
+               SNIC_HOST_INFO(snic->shost, "desc_avail: Multi Queue case.\n");
+               SNIC_BUG_ON(q_num > 0);
+
+               return -1;
+       }
+
+       nr_wqdesc -= atomic64_read(&snic->s_stats.fw.actv_reqs);
+
+       return ((req_type == SNIC_REQ_HBA_RESET) ? nr_wqdesc : nr_wqdesc - 1);
+}
+
 int
 snic_queue_wq_desc(struct snic *snic, void *os_buf, u16 len)
 {
        dma_addr_t pa = 0;
        unsigned long flags;
        struct snic_fw_stats *fwstats = &snic->s_stats.fw;
+       struct snic_host_req *req = (struct snic_host_req *) os_buf;
        long act_reqs;
+       long desc_avail = 0;
        int q_num = 0;
 
        snic_print_desc(__func__, os_buf, len);
@@ -156,11 +179,15 @@ snic_queue_wq_desc(struct snic *snic, void *os_buf, u16 len)
                return -ENOMEM;
        }
 
+       req->req_pa = (ulong)pa;
+
        q_num = snic_select_wq(snic);
 
        spin_lock_irqsave(&snic->wq_lock[q_num], flags);
-       if (!svnic_wq_desc_avail(snic->wq)) {
+       desc_avail = snic_wqdesc_avail(snic, q_num, req->hdr.type);
+       if (desc_avail <= 0) {
                pci_unmap_single(snic->pdev, pa, len, PCI_DMA_TODEVICE);
+               req->req_pa = 0;
                spin_unlock_irqrestore(&snic->wq_lock[q_num], flags);
                atomic64_inc(&snic->s_stats.misc.wq_alloc_fail);
                SNIC_DBG("host = %d, WQ is Full\n", snic->shost->host_no);
@@ -169,10 +196,13 @@ snic_queue_wq_desc(struct snic *snic, void *os_buf, u16 len)
        }
 
        snic_queue_wq_eth_desc(&snic->wq[q_num], os_buf, pa, len, 0, 0, 1);
+       /*
+        * Update stats
+        * note: when multi queue enabled, fw actv_reqs should be per queue.
+        */
+       act_reqs = atomic64_inc_return(&fwstats->actv_reqs);
        spin_unlock_irqrestore(&snic->wq_lock[q_num], flags);
 
-       /* Update stats */
-       act_reqs = atomic64_inc_return(&fwstats->actv_reqs);
        if (act_reqs > atomic64_read(&fwstats->max_actv_reqs))
                atomic64_set(&fwstats->max_actv_reqs, act_reqs);
 
@@ -318,11 +348,31 @@ snic_req_free(struct snic *snic, struct snic_req_info *rqi)
                      "Req_free:rqi %p:ioreq %p:abt %p:dr %p\n",
                      rqi, rqi->req, rqi->abort_req, rqi->dr_req);
 
-       if (rqi->abort_req)
+       if (rqi->abort_req) {
+               if (rqi->abort_req->req_pa)
+                       pci_unmap_single(snic->pdev,
+                                        rqi->abort_req->req_pa,
+                                        sizeof(struct snic_host_req),
+                                        PCI_DMA_TODEVICE);
+
                mempool_free(rqi->abort_req, snic->req_pool[SNIC_REQ_TM_CACHE]);
+       }
+
+       if (rqi->dr_req) {
+               if (rqi->dr_req->req_pa)
+                       pci_unmap_single(snic->pdev,
+                                        rqi->dr_req->req_pa,
+                                        sizeof(struct snic_host_req),
+                                        PCI_DMA_TODEVICE);
 
-       if (rqi->dr_req)
                mempool_free(rqi->dr_req, snic->req_pool[SNIC_REQ_TM_CACHE]);
+       }
+
+       if (rqi->req->req_pa)
+               pci_unmap_single(snic->pdev,
+                                rqi->req->req_pa,
+                                rqi->req_len,
+                                PCI_DMA_TODEVICE);
 
        mempool_free(rqi, snic->req_pool[rqi->rq_pool_type]);
 }