src/patches/suse-2.6.27.25/patches.arch/s390-10-03-zfcp_els_thread_context.patch

   1 From: Gerald Schaefer <geraldsc@de.ibm.com>
   2 Subject: zfcp: Send ELS ADISC from workqueue
   3 References: bnc#482818,LTC#51958
   4
   5 Symptom:     Remote port status change not handled
   6              with high I/O load on other ports.
   7 Problem:     The ELS ADISC command used for checking
   8              the remote port status could not be sent
   9              because of a full request queue.
  10 Solution:    Move issing the ELS ADISC request to
  11              a workqueue that can wait for a slot
  12              in the request queue to become free.
  13
  14 Acked-by: John Jolly <jjolly@suse.de>
  15 ---
  16  drivers/s390/scsi/zfcp_aux.c |    1 +
  17  drivers/s390/scsi/zfcp_def.h |    1 +
  18  drivers/s390/scsi/zfcp_ext.h |    1 +
  19  drivers/s390/scsi/zfcp_fc.c  |   28 ++++++++++++++++++----------
  20  drivers/s390/scsi/zfcp_fsf.c |   18 ++++++------------
  21  5 files changed, 27 insertions(+), 22 deletions(-)
  22
  23 --- a/drivers/s390/scsi/zfcp_aux.c
  24 +++ b/drivers/s390/scsi/zfcp_aux.c
  25 @@ -611,6 +611,7 @@ struct zfcp_port *zfcp_port_enqueue(stru
  26         init_waitqueue_head(&port->remove_wq);
  27         INIT_LIST_HEAD(&port->unit_list_head);
  28         INIT_WORK(&port->gid_pn_work, zfcp_erp_port_strategy_open_lookup);
  29 +       INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
  30
  31         port->adapter = adapter;
  32         port->d_id = d_id;
  33 --- a/drivers/s390/scsi/zfcp_def.h
  34 +++ b/drivers/s390/scsi/zfcp_def.h
  35 @@ -539,6 +539,7 @@ struct zfcp_port {
  36         u32                    maxframe_size;
  37         u32                    supported_classes;
  38         struct work_struct     gid_pn_work;
  39 +       struct work_struct     test_link_work;
  40  };
  41
  42  struct zfcp_unit {
  43 --- a/drivers/s390/scsi/zfcp_ext.h
  44 +++ b/drivers/s390/scsi/zfcp_ext.h
  45 @@ -101,6 +101,7 @@ extern void zfcp_fc_incoming_els(struct
  46  extern int zfcp_fc_ns_gid_pn(struct zfcp_erp_action *);
  47  extern void zfcp_fc_plogi_evaluate(struct zfcp_port *, struct fsf_plogi *);
  48  extern void zfcp_test_link(struct zfcp_port *);
  49 +extern void zfcp_fc_link_test_work(struct work_struct *);
  50  extern void zfcp_fc_nameserver_init(struct zfcp_adapter *);
  51
  52  /* zfcp_fsf.c */
  53 --- a/drivers/s390/scsi/zfcp_fc.c
  54 +++ b/drivers/s390/scsi/zfcp_fc.c
  55 @@ -415,19 +415,12 @@ static int zfcp_fc_adisc(struct zfcp_por
  56         return zfcp_fsf_send_els(&adisc->els);
  57  }
  58
  59 -/**
  60 - * zfcp_test_link - lightweight link test procedure
  61 - * @port: port to be tested
  62 - *
  63 - * Test status of a link to a remote port using the ELS command ADISC.
  64 - * If there is a problem with the remote port, error recovery steps
  65 - * will be triggered.
  66 - */
  67 -void zfcp_test_link(struct zfcp_port *port)
  68 +void zfcp_fc_link_test_work(struct work_struct *work)
  69  {
  70 +       struct zfcp_port *port =
  71 +               container_of(work, struct zfcp_port, test_link_work);
  72         int retval;
  73
  74 -       zfcp_port_get(port);
  75         retval = zfcp_fc_adisc(port);
  76         if (retval == 0)
  77                 return;
  78 @@ -438,6 +431,21 @@ void zfcp_test_link(struct zfcp_port *po
  79                 zfcp_erp_port_forced_reopen(port, 0, 65, NULL);
  80  }
  81
  82 +/**
  83 + * zfcp_test_link - lightweight link test procedure
  84 + * @port: port to be tested
  85 + *
  86 + * Test status of a link to a remote port using the ELS command ADISC.
  87 + * If there is a problem with the remote port, error recovery steps
  88 + * will be triggered.
  89 + */
  90 +void zfcp_test_link(struct zfcp_port *port)
  91 +{
  92 +       zfcp_port_get(port);
  93 +       if (!queue_work(zfcp_data.work_queue, &port->test_link_work))
  94 +               zfcp_port_put(port);
  95 +}
  96 +
  97  static void zfcp_free_sg_env(struct zfcp_gpn_ft *gpn_ft, int buf_num)
  98  {
  99         struct scatterlist *sg = &gpn_ft->sg_req;
 100 --- a/drivers/s390/scsi/zfcp_fsf.c
 101 +++ b/drivers/s390/scsi/zfcp_fsf.c
 102 @@ -654,14 +654,6 @@ static int zfcp_fsf_sbal_check(struct zf
 103         return 0;
 104  }
 105
 106 -static int zfcp_fsf_sbal_available(struct zfcp_adapter *adapter)
 107 -{
 108 -       unsigned int count = atomic_read(&adapter->req_q.count);
 109 -       if (!count)
 110 -               atomic_inc(&adapter->qdio_outb_full);
 111 -       return count > 0;
 112 -}
 113 -
 114  static int zfcp_fsf_req_sbal_get(struct zfcp_adapter *adapter)
 115  {
 116         long ret;
 117 @@ -1177,8 +1169,8 @@ int zfcp_fsf_send_els(struct zfcp_send_e
 118                        ZFCP_STATUS_COMMON_UNBLOCKED)))
 119                 return -EBUSY;
 120
 121 -       spin_lock(&adapter->req_q_lock);
 122 -       if (!zfcp_fsf_sbal_available(adapter))
 123 +       spin_lock_bh(&adapter->req_q_lock);
 124 +       if (zfcp_fsf_req_sbal_get(adapter))
 125                 goto out;
 126         req = zfcp_fsf_req_create(adapter, FSF_QTCB_SEND_ELS,
 127                                   ZFCP_REQ_AUTO_CLEANUP, NULL);
 128 @@ -1211,7 +1203,7 @@ int zfcp_fsf_send_els(struct zfcp_send_e
 129  failed_send:
 130         zfcp_fsf_req_free(req);
 131  out:
 132 -       spin_unlock(&adapter->req_q_lock);
 133 +       spin_unlock_bh(&adapter->req_q_lock);
 134         return ret;
 135  }
 136
 137 @@ -2336,8 +2328,10 @@ int zfcp_fsf_send_fcp_command_task(struc
 138                 return -EBUSY;
 139
 140         spin_lock(&adapter->req_q_lock);
 141 -       if (!zfcp_fsf_sbal_available(adapter))
 142 +       if (atomic_read(&adapter->req_q.count) <= 0) {
 143 +               atomic_inc(&adapter->qdio_outb_full);
 144                 goto out;
 145 +       }
 146         req = zfcp_fsf_req_create(adapter, FSF_QTCB_FCP_CMND, req_flags,
 147                                   adapter->pool.fsf_req_scsi);
 148         if (IS_ERR(req)) {