src/patches/suse-2.6.27.39/patches.fixes/scsi-ses-hotplug-fix

   1 From: James Bottomley <James.Bottomley@HansenPartnership.com>
   2 Date: Sat, 1 Aug 2009 00:39:36 +0000
   3 Subject: [PATCH] [SCSI] ses: fix hotplug with multiple devices and expanders
   4 X-Git: 163f52b6cf3a639df6a72c7937e0eb88b20f1ef3
   5 References: bnc#549751
   6
   7 In a situation either with expanders or with multiple enclosure
   8 devices, hot add doesn't always work.  This is because we try to find
   9 a single enclosure device attached to the host.  Fix this by looping
  10 over all enclosure devices attached to the host and also by making the
  11 find loop recognise that the enclosure devices may be expander remote
  12 (i.e. not parented by the host).
  13
  14 Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
  15 Signed-off-by: James Bottomley <James.Bottomley@suse.de>
  16
  17 diff --git a/drivers/misc/enclosure.c b/drivers/misc/enclosure.c
  18 index 348443b..789d121 100644
  19 --- a/drivers/misc/enclosure.c
  20 +++ b/drivers/misc/enclosure.c
  21 @@ -33,24 +33,44 @@ static DEFINE_MUTEX(container_list_lock);
  22  static struct class enclosure_class;
  23
  24  /**
  25 - * enclosure_find - find an enclosure given a device
  26 - * @dev:       the device to find for
  27 + * enclosure_find - find an enclosure given a parent device
  28 + * @dev:       the parent to match against
  29 + * @start:     Optional enclosure device to start from (NULL if none)
  30   *
  31 - * Looks through the list of registered enclosures to see
  32 - * if it can find a match for a device.  Returns NULL if no
  33 - * enclosure is found. Obtains a reference to the enclosure class
  34 - * device which must be released with device_put().
  35 + * Looks through the list of registered enclosures to find all those
  36 + * with @dev as a parent.  Returns NULL if no enclosure is
  37 + * found. @start can be used as a starting point to obtain multiple
  38 + * enclosures per parent (should begin with NULL and then be set to
  39 + * each returned enclosure device). Obtains a reference to the
  40 + * enclosure class device which must be released with device_put().
  41 + * If @start is not NULL, a reference must be taken on it which is
  42 + * released before returning (this allows a loop through all
  43 + * enclosures to exit with only the reference on the enclosure of
  44 + * interest held).  Note that the @dev may correspond to the actual
  45 + * device housing the enclosure, in which case no iteration via @start
  46 + * is required.
  47   */
  48 -struct enclosure_device *enclosure_find(struct device *dev)
  49 +struct enclosure_device *enclosure_find(struct device *dev,
  50 +                                       struct enclosure_device *start)
  51  {
  52         struct enclosure_device *edev;
  53
  54         mutex_lock(&container_list_lock);
  55 -       list_for_each_entry(edev, &container_list, node) {
  56 -               if (edev->edev.parent == dev) {
  57 -                       get_device(&edev->edev);
  58 -                       mutex_unlock(&container_list_lock);
  59 -                       return edev;
  60 +       edev = list_prepare_entry(start, &container_list, node);
  61 +       if (start)
  62 +               put_device(&start->edev);
  63 +
  64 +       list_for_each_entry_continue(edev, &container_list, node) {
  65 +               struct device *parent = edev->edev.parent;
  66 +               /* parent might not be immediate, so iterate up to
  67 +                * the root of the tree if necessary */
  68 +               while (parent) {
  69 +                       if (parent == dev) {
  70 +                               get_device(&edev->edev);
  71 +                               mutex_unlock(&container_list_lock);
  72 +                               return edev;
  73 +                       }
  74 +                       parent = parent->parent;
  75                 }
  76         }
  77         mutex_unlock(&container_list_lock);
  78 diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
  79 index 4f618f4..e1b8c82 100644
  80 --- a/drivers/scsi/ses.c
  81 +++ b/drivers/scsi/ses.c
  82 @@ -413,10 +413,11 @@ static int ses_intf_add(struct device *cdev,
  83
  84         if (!scsi_device_enclosure(sdev)) {
  85                 /* not an enclosure, but might be in one */
  86 -               edev = enclosure_find(&sdev->host->shost_gendev);
  87 -               if (edev) {
  88 +               struct enclosure_device *prev = NULL;
  89 +
  90 +               while ((edev = enclosure_find(&sdev->host->shost_gendev, prev)) != NULL) {
  91                         ses_match_to_enclosure(edev, sdev);
  92 -                       put_device(&edev->edev);
  93 +                       prev = edev;
  94                 }
  95                 return -ENODEV;
  96         }
  97 @@ -625,7 +626,8 @@ static void ses_intf_remove(struct device *cdev,
  98         if (!scsi_device_enclosure(sdev))
  99                 return;
 100
 101 -       edev = enclosure_find(cdev->parent);
 102 +       /*  exact match to this enclosure */
 103 +       edev = enclosure_find(cdev->parent, NULL);
 104         if (!edev)
 105                 return;
 106
 107 diff --git a/include/linux/enclosure.h b/include/linux/enclosure.h
 108 index 4332442..d77811e 100644
 109 --- a/include/linux/enclosure.h
 110 +++ b/include/linux/enclosure.h
 111 @@ -123,7 +123,8 @@ enclosure_component_register(struct enclosure_device *, unsigned int,
 112  int enclosure_add_device(struct enclosure_device *enclosure, int component,
 113                          struct device *dev);
 114  int enclosure_remove_device(struct enclosure_device *enclosure, int component);
 115 -struct enclosure_device *enclosure_find(struct device *dev);
 116 +struct enclosure_device *enclosure_find(struct device *dev,
 117 +                                       struct enclosure_device *start);
 118  int enclosure_for_each_device(int (*fn)(struct enclosure_device *, void *),
 119                               void *data);
 120