src/patches/suse-2.6.27.31/patches.fixes/scsi-dh-queuedata-accessors

   1 From: Hannes Reinecke <hare@suse.de>
   2 Subject: Kernel bug triggered in multipath
   3 References: bnc#486001
   4
   5 Starting multipath on a cciss device will cause a kernel
   6 warning to be triggered. Problem is that we're using the
   7 ->queuedata field of the request_queue to derefence the
   8 scsi device; however, for other (non-SCSI) devices this
   9 points to a totally different structure.
  10 So we should rather be using accessors here which make
  11 sure we're only returning valid SCSI device structures.
  12
  13 Signed-off-by: Hannes Reinecke <hare@suse.de>
  14
  15 ---
  16  drivers/scsi/device_handler/scsi_dh.c |   10 +++++-----
  17  drivers/scsi/scsi_lib.c               |   11 +++++++++++
  18  include/scsi/scsi_device.h            |    1 +
  19  3 files changed, 17 insertions(+), 5 deletions(-)
  20
  21 --- a/drivers/scsi/device_handler/scsi_dh.c
  22 +++ b/drivers/scsi/device_handler/scsi_dh.c
  23 @@ -427,7 +427,7 @@ int scsi_dh_activate(struct request_queu
  24         struct scsi_device_handler *scsi_dh = NULL;
  25
  26         spin_lock_irqsave(q->queue_lock, flags);
  27 -       sdev = q->queuedata;
  28 +       sdev = scsi_device_from_queue(q);
  29         if (sdev && sdev->scsi_dh_data)
  30                 scsi_dh = sdev->scsi_dh_data->scsi_dh;
  31         if (!scsi_dh || !get_device(&sdev->sdev_gendev))
  32 @@ -456,7 +456,7 @@ int scsi_dh_handler_exist(const char *na
  33  EXPORT_SYMBOL_GPL(scsi_dh_handler_exist);
  34
  35  /*
  36 - * scsi_dh_handler_attach - Attach device handler
  37 + * scsi_dh_attach - Attach device handler
  38   * @sdev - sdev the handler should be attached to
  39   * @name - name of the handler to attach
  40   */
  41 @@ -472,7 +472,7 @@ int scsi_dh_attach(struct request_queue
  42                 return -EINVAL;
  43
  44         spin_lock_irqsave(q->queue_lock, flags);
  45 -       sdev = q->queuedata;
  46 +       sdev = scsi_device_from_queue(q);
  47         if (!sdev || !get_device(&sdev->sdev_gendev))
  48                 err = -ENODEV;
  49         spin_unlock_irqrestore(q->queue_lock, flags);
  50 @@ -487,7 +487,7 @@ int scsi_dh_attach(struct request_queue
  51  EXPORT_SYMBOL_GPL(scsi_dh_attach);
  52
  53  /*
  54 - * scsi_dh_handler_detach - Detach device handler
  55 + * scsi_dh_detach - Detach device handler
  56   * @sdev - sdev the handler should be detached from
  57   *
  58   * This function will detach the device handler only
  59 @@ -501,7 +501,7 @@ void scsi_dh_detach(struct request_queue
  60         struct scsi_device_handler *scsi_dh = NULL;
  61
  62         spin_lock_irqsave(q->queue_lock, flags);
  63 -       sdev = q->queuedata;
  64 +       sdev = scsi_device_from_queue(q);
  65         if (!sdev || !get_device(&sdev->sdev_gendev))
  66                 sdev = NULL;
  67         spin_unlock_irqrestore(q->queue_lock, flags);
  68 --- a/drivers/scsi/scsi_lib.c
  69 +++ b/drivers/scsi/scsi_lib.c
  70 @@ -1696,6 +1696,17 @@ static void scsi_request_fn(struct reque
  71         spin_lock_irq(q->queue_lock);
  72  }
  73
  74 +struct scsi_device *scsi_device_from_queue(struct request_queue *q)
  75 +{
  76 +       struct scsi_device *sdev = NULL;
  77 +
  78 +       if (q->request_fn == scsi_request_fn)
  79 +               sdev = q->queuedata;
  80 +
  81 +       return sdev;
  82 +}
  83 +EXPORT_SYMBOL_GPL(scsi_device_from_queue);
  84 +
  85  u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
  86  {
  87         struct device *host_dev;
  88 --- a/include/scsi/scsi_device.h
  89 +++ b/include/scsi/scsi_device.h
  90 @@ -291,6 +291,7 @@ extern void starget_for_each_device(stru
  91  extern void __starget_for_each_device(struct scsi_target *, void *,
  92                                       void (*fn)(struct scsi_device *,
  93                                                  void *));
  94 +extern struct scsi_device *scsi_device_from_queue(struct request_queue *);
  95
  96  /* only exposed to implement shost_for_each_device */
  97  extern struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *,