[SCSI] zfcp: Send ELS ADISC from workqueue

Issue ELS ADISC requests from workqueue. This allows the link test
request to be sent when the request queue is full due to I/O load for
other remote ports. It also simplifies request queue locking,
zfcp_fsf_send_fcp_command_task is now the only function that has
interrupts disabled from the caller. This is also a prereq for the FC
passthrough support that issues ELS requests from userspace.

Acked-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 6 insertions, 12 deletions

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index cc69db3b71e7..9c3f91a343f3 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -647,14 +647,6 @@ static void zfcp_fsf_exchange_port_data_handler(struct zfcp_fsf_req *req)
         }
 }
 
-static int zfcp_fsf_sbal_available(struct zfcp_adapter *adapter)
-{
-        if (atomic_read(&adapter->req_q.count) > 0)
-                return 1;
-        atomic_inc(&adapter->qdio_outb_full);
-        return 0;
-}
-
 static int zfcp_fsf_req_sbal_get(struct zfcp_adapter *adapter)
         __releases(&adapter->req_q_lock)
         __acquires(&adapter->req_q_lock)
@@ -1177,8 +1169,8 @@ int zfcp_fsf_send_els(struct zfcp_send_els *els)
                        ZFCP_STATUS_COMMON_UNBLOCKED)))
                 return -EBUSY;
 
-        spin_lock(&adapter->req_q_lock);
-        if (!zfcp_fsf_sbal_available(adapter))
+        spin_lock_bh(&adapter->req_q_lock);
+        if (zfcp_fsf_req_sbal_get(adapter))
                 goto out;
         req = zfcp_fsf_req_create(adapter, FSF_QTCB_SEND_ELS,
                                   ZFCP_REQ_AUTO_CLEANUP, NULL);
@@ -1211,7 +1203,7 @@ int zfcp_fsf_send_els(struct zfcp_send_els *els)
 failed_send:
         zfcp_fsf_req_free(req);
 out:
-        spin_unlock(&adapter->req_q_lock);
+        spin_unlock_bh(&adapter->req_q_lock);
         return ret;
 }
 
@@ -2324,8 +2316,10 @@ int zfcp_fsf_send_fcp_command_task(struct zfcp_unit *unit,
                 return -EBUSY;
 
         spin_lock(&adapter->req_q_lock);
-        if (!zfcp_fsf_sbal_available(adapter))
+        if (atomic_read(&adapter->req_q.count) <= 0) {
+                atomic_inc(&adapter->qdio_outb_full);
                 goto out;
+        }
         req = zfcp_fsf_req_create(adapter, FSF_QTCB_FCP_CMND,
                                   ZFCP_REQ_AUTO_CLEANUP,
                                   adapter->pool.fsf_req_scsi);