be2iscsi: Fix soft lockup in mgmt_get_all_if_id path using bmbx

We are taking mbox_lock spinlock which disables pre-emption before we
poll for mbox completion. Waiting there with spinlock held in excess of
20s will cause soft lockup.

Actual fix is to change mbox_lock to mutex. The changes are done in
phases. This is the first part.

1. Changed mgmt_get_all_if_id to use MCC where after posting lock is
released.

2. Changed be_mbox_db_ready_wait to busy wait for 12s max and removed
wait_event_timeout. Added error handling code for IO reads.
OPCODE_COMMON_QUERY_FIRMWARE_CONFIG mbox command takes 8s time when
unreachable boot targets configured.

Signed-off-by: Jitendra Bhivare <jitendra.bhivare@avagotech.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/be2iscsi/be_cmds.c b/drivers/scsi/be2iscsi/be_cmds.c
index 2778089b01a578c5954686218c69b07b368e94cd..cd50e3ce35a662bd72b9fda33ba8511bf56af138 100644 (file)
--- a/drivers/scsi/be2iscsi/be_cmds.c
+++ b/drivers/scsi/be2iscsi/be_cmds.c
@@ -587,47 +587,42 @@ int be_mcc_notify_wait(struct beiscsi_hba *phba)
  **/
 static int be_mbox_db_ready_wait(struct be_ctrl_info *ctrl)
 {
-#define BEISCSI_MBX_RDY_BIT_TIMEOUT    4000    /* 4sec */
+#define BEISCSI_MBX_RDY_BIT_TIMEOUT    12000   /* 12sec */
        void __iomem *db = ctrl->db + MPU_MAILBOX_DB_OFFSET;
        struct beiscsi_hba *phba = pci_get_drvdata(ctrl->pdev);
        unsigned long timeout;
-       bool read_flag = false;
-       int ret = 0, i;
        u32 ready;
-       DECLARE_WAIT_QUEUE_HEAD_ONSTACK(rdybit_check_q);
 
-       if (beiscsi_error(phba))
-               return -EIO;
+       /*
+        * This BMBX busy wait path is used during init only.
+        * For the commands executed during init, 5s should suffice.
+        */
+       timeout = jiffies + msecs_to_jiffies(BEISCSI_MBX_RDY_BIT_TIMEOUT);
+       do {
+               if (beiscsi_error(phba))
+                       return -EIO;
 
-       timeout = jiffies + (HZ * 110);
+               ready = ioread32(db);
+               if (ready == 0xffffffff)
+                       return -EIO;
 
-       do {
-               for (i = 0; i < BEISCSI_MBX_RDY_BIT_TIMEOUT; i++) {
-                       ready = ioread32(db) & MPU_MAILBOX_DB_RDY_MASK;
-                       if (ready) {
-                               read_flag = true;
-                               break;
-                       }
-                       mdelay(1);
-               }
+               ready &= MPU_MAILBOX_DB_RDY_MASK;
+               if (ready)
+                       return 0;
 
-               if (!read_flag) {
-                       wait_event_timeout(rdybit_check_q,
-                                         (read_flag != true),
-                                          HZ * 5);
-               }
-       } while ((time_before(jiffies, timeout)) && !read_flag);
+               if (time_after(jiffies, timeout))
+                       break;
+               mdelay(1);
+       } while (!ready);
 
-       if (!read_flag) {
-               beiscsi_log(phba, KERN_ERR,
-                           BEISCSI_LOG_CONFIG | BEISCSI_LOG_MBOX,
-                           "BC_%d : FW Timed Out\n");
-                       phba->fw_timeout = true;
-                       beiscsi_ue_detect(phba);
-                       ret = -EBUSY;
-       }
+       beiscsi_log(phba, KERN_ERR,
+                       BEISCSI_LOG_CONFIG | BEISCSI_LOG_MBOX,
+                       "BC_%d : FW Timed Out\n");
 
-       return ret;
+       phba->fw_timeout = true;
+       beiscsi_ue_detect(phba);
+
+       return -EBUSY;
 }
 
 /*
@@ -674,6 +669,9 @@ int be_mbox_notify(struct be_ctrl_info *ctrl)
        if (status)
                return status;
 
+       /* RDY is set; small delay before CQE read. */
+       udelay(1);
+
        if (be_mcc_compl_is_new(compl)) {
                status = be_mcc_compl_process(ctrl, &mbox->compl);
                be_mcc_compl_use(compl);

diff --git a/drivers/scsi/be2iscsi/be_mgmt.c b/drivers/scsi/be2iscsi/be_mgmt.c
index aea3e6b9477dcc73df18b263365609a93abd3758..7b54b23e756e5df8b03082748335a4cf4734c452 100644 (file)
--- a/drivers/scsi/be2iscsi/be_mgmt.c
+++ b/drivers/scsi/be2iscsi/be_mgmt.c
@@ -809,27 +809,39 @@ int mgmt_open_connection(struct beiscsi_hba *phba,
 unsigned int mgmt_get_all_if_id(struct beiscsi_hba *phba)
 {
        struct be_ctrl_info *ctrl = &phba->ctrl;
-       struct be_mcc_wrb *wrb = wrb_from_mbox(&ctrl->mbox_mem);
-       struct be_cmd_get_all_if_id_req *req = embedded_payload(wrb);
-       struct be_cmd_get_all_if_id_req *pbe_allid = req;
+       struct be_mcc_wrb *wrb;
+       struct be_cmd_get_all_if_id_req *req;
+       struct be_cmd_get_all_if_id_req *pbe_allid;
+       unsigned int tag;
        int status = 0;
 
-       memset(wrb, 0, sizeof(*wrb));
-
        spin_lock(&ctrl->mbox_lock);
+       tag = alloc_mcc_tag(phba);
+       if (!tag) {
+               spin_unlock(&ctrl->mbox_lock);
+               return -ENOMEM;
+       }
+
+       wrb = wrb_from_mccq(phba);
+       req = embedded_payload(wrb);
+       wrb->tag0 |= tag;
 
        be_wrb_hdr_prepare(wrb, sizeof(*req), true, 0);
        be_cmd_hdr_prepare(&req->hdr, CMD_SUBSYSTEM_ISCSI,
                           OPCODE_COMMON_ISCSI_NTWK_GET_ALL_IF_ID,
                           sizeof(*req));
-       status = be_mbox_notify(ctrl);
-       if (!status)
-               phba->interface_handle = pbe_allid->if_hndl_list[0];
-       else {
+       be_mcc_notify(phba);
+       spin_unlock(&ctrl->mbox_lock);
+
+       status = beiscsi_mccq_compl(phba, tag, &wrb, NULL);
+       if (status) {
                beiscsi_log(phba, KERN_WARNING, BEISCSI_LOG_CONFIG,
                            "BG_%d : Failed in mgmt_get_all_if_id\n");
+               return -EBUSY;
        }
-       spin_unlock(&ctrl->mbox_lock);
+
+       pbe_allid = embedded_payload(wrb);
+       phba->interface_handle = pbe_allid->if_hndl_list[0];
 
        return status;
 }