src/patches/suse-2.6.27.31/patches.fixes/scsi-ibmvscsi-can_queue_fix.patch

   1 Subject: Make max_requests module parameter more accurate
   2 From: Brian King <brking@linux.vnet.ibm.com>
   3 References: 458499 - LTC50637
   4
   5 In a previous patch to fix an issue with error recovery,
   6 the behavior of the max_requests module paramater was also
   7 changed. If, for some reason, max_requests is set to one by
   8 the user, we will end up with a negative number for can_queue.
   9 Fix this by making max_requests not include the two event structs
  10 needed to do error recovery.
  11
  12 Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
  13 Signed-off-by: Olaf Hering <olh@suse.de>
  14
  15 ---
  16  drivers/scsi/ibmvscsi/ibmvscsi.c |   17 +++++++++++------
  17  1 file changed, 11 insertions(+), 6 deletions(-)
  18
  19 --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
  20 +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
  21 @@ -89,6 +89,8 @@ static int max_id = 64;
  22  static int max_channel = 3;
  23  static int init_timeout = 5;
  24  static int max_requests = IBMVSCSI_MAX_REQUESTS_DEFAULT;
  25 +static int max_events = IBMVSCSI_MAX_REQUESTS_DEFAULT + 2;
  26 +
  27  /*host data buffer size*/
  28  #define buff_size 4096
  29
  30 @@ -1635,7 +1637,7 @@ static struct scsi_host_template driver_
  31  static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
  32  {
  33         /* iu_storage data allocated in initialize_event_pool */
  34 -       unsigned long desired_io = max_requests * sizeof(union viosrp_iu);
  35 +       unsigned long desired_io = max_events * sizeof(union viosrp_iu);
  36
  37         /* add io space for sg data */
  38         desired_io += (IBMVSCSI_MAX_SECTORS_DEFAULT * 512 *
  39 @@ -1659,7 +1661,6 @@ static int ibmvscsi_probe(struct vio_dev
  40
  41         vdev->dev.driver_data = NULL;
  42
  43 -       driver_template.can_queue = max_requests;
  44         host = scsi_host_alloc(&driver_template, sizeof(*hostdata));
  45         if (!host) {
  46                 dev_err(&vdev->dev, "couldn't allocate host data\n");
  47 @@ -1675,12 +1676,12 @@ static int ibmvscsi_probe(struct vio_dev
  48         atomic_set(&hostdata->request_limit, -1);
  49         hostdata->host->max_sectors = IBMVSCSI_MAX_SECTORS_DEFAULT;
  50
  51 -       rc = ibmvscsi_ops->init_crq_queue(&hostdata->queue, hostdata, max_requests);
  52 +       rc = ibmvscsi_ops->init_crq_queue(&hostdata->queue, hostdata, max_events);
  53         if (rc != 0 && rc != H_RESOURCE) {
  54                 dev_err(&vdev->dev, "couldn't initialize crq. rc=%d\n", rc);
  55                 goto init_crq_failed;
  56         }
  57 -       if (initialize_event_pool(&hostdata->pool, max_requests, hostdata) != 0) {
  58 +       if (initialize_event_pool(&hostdata->pool, max_events, hostdata) != 0) {
  59                 dev_err(&vdev->dev, "couldn't initialize event pool\n");
  60                 goto init_pool_failed;
  61         }
  62 @@ -1732,7 +1733,7 @@ static int ibmvscsi_probe(struct vio_dev
  63        add_host_failed:
  64         release_event_pool(&hostdata->pool, hostdata);
  65        init_pool_failed:
  66 -       ibmvscsi_ops->release_crq_queue(&hostdata->queue, hostdata, max_requests);
  67 +       ibmvscsi_ops->release_crq_queue(&hostdata->queue, hostdata, max_events);
  68        init_crq_failed:
  69         scsi_host_put(host);
  70        scsi_host_alloc_failed:
  71 @@ -1744,7 +1745,7 @@ static int ibmvscsi_remove(struct vio_de
  72         struct ibmvscsi_host_data *hostdata = vdev->dev.driver_data;
  73         release_event_pool(&hostdata->pool, hostdata);
  74         ibmvscsi_ops->release_crq_queue(&hostdata->queue, hostdata,
  75 -                                       max_requests);
  76 +                                       max_events);
  77
  78         srp_remove_host(hostdata->host);
  79         scsi_remove_host(hostdata->host);
  80 @@ -1781,6 +1782,10 @@ int __init ibmvscsi_module_init(void)
  81  {
  82         int ret;
  83
  84 +       /* Ensure we have two requests to do error recovery */
  85 +       driver_template.can_queue = max_requests;
  86 +       max_events = max_requests + 2;
  87 +
  88         if (firmware_has_feature(FW_FEATURE_ISERIES))
  89                 ibmvscsi_ops = &iseriesvscsi_ops;
  90         else if (firmware_has_feature(FW_FEATURE_VIO))