src/patches/suse-2.6.27.31/patches.arch/s390-16-01-zfcp-link-test.patch

   1 From: Gerald Schaefer <geraldsc@de.ibm.com>
   2 Subject: zfcp: Only issue one test link command per port
   3 References: bnc#529188,LTC#55337
   4
   5 Symptom:     During error recovery, the SAN trace shows a long series
   6              of els adisc commands being issued to the same remote port.
   7 Problem:     When the FCP channel returns a series of failed commands,
   8              a els adisc test link command is issued for each failed
   9              command.
  10 Solution:    Introduce a flag to ensure only one els adisc is pending
  11              at one time. This is enough to trigger follow-on actions.
  12
  13 Acked-by: John Jolly <jjolly@suse.de>
  14 ---
  15  drivers/s390/scsi/zfcp_def.h |    1 +
  16  drivers/s390/scsi/zfcp_fc.c  |    9 +++++++++
  17  2 files changed, 10 insertions(+)
  18
  19 --- a/drivers/s390/scsi/zfcp_def.h      2009-07-16 12:20:57.000000000 +0200
  20 +++ b/drivers/s390/scsi/zfcp_def.h      2009-07-16 12:22:20.000000000 +0200
  21 @@ -260,6 +260,7 @@ struct zfcp_ls_adisc {
  22  #define ZFCP_STATUS_PORT_PHYS_CLOSING          0x00000004
  23  #define ZFCP_STATUS_PORT_NO_WWPN               0x00000008
  24  #define ZFCP_STATUS_PORT_INVALID_WWPN          0x00000020
  25 +#define ZFCP_STATUS_PORT_LINK_TEST             0x00000040
  26
  27  /* well known address (WKA) port status*/
  28  enum zfcp_wka_status {
  29 --- a/drivers/s390/scsi/zfcp_fc.c       2009-07-16 12:20:57.000000000 +0200
  30 +++ b/drivers/s390/scsi/zfcp_fc.c       2009-07-16 12:23:15.000000000 +0200
  31 @@ -389,6 +389,7 @@ static void zfcp_fc_adisc_handler(unsign
  32         zfcp_scsi_schedule_rport_register(port);
  33
  34   out:
  35 +       atomic_clear_mask(ZFCP_STATUS_PORT_LINK_TEST, &port->status);
  36         zfcp_port_put(port);
  37         kfree(adisc);
  38  }
  39 @@ -435,13 +436,21 @@ void zfcp_fc_link_test_work(struct work_
  40         port->rport_task = RPORT_DEL;
  41         zfcp_scsi_rport_work(&port->rport_work);
  42
  43 +       /* only issue one test command at one time per port */
  44 +       if (atomic_read(&port->status) & ZFCP_STATUS_PORT_LINK_TEST)
  45 +               goto out;
  46 +
  47 +       atomic_set_mask(ZFCP_STATUS_PORT_LINK_TEST, &port->status);
  48 +
  49         retval = zfcp_fc_adisc(port);
  50         if (retval == 0)
  51                 return;
  52
  53         /* send of ADISC was not possible */
  54 +       atomic_clear_mask(ZFCP_STATUS_PORT_LINK_TEST, &port->status);
  55         zfcp_erp_port_forced_reopen(port, 0, 65, NULL);
  56
  57 +out:
  58         zfcp_port_put(port);
  59  }
  60