From: Mike Christie <michaelc@xxxxxxxxxxx>
In 2.6.25 we started using class_find_child instead of implementing
our own loop and lookup. The problem is that class_find_child would get a
reference to the host's device, then scsi_host_lookup would get an extra
reference to it when it called scsi_host_get().
In 2.6.26 we started using class_find_device, and this function also
gets a reference to the device, so we end up with an extra ref
and the host will not get released.
This patch is made against scsi-rc-fixes and adds a put_device to
balance the class_find_device() get. I kept the scsi_host_get in
scsi_host_lookup, because the target layer is using scsi_host_lookup
and it looks like it needs the SHOST_DEL check.
For 2.6.25 we need a similar patch, but instead of calling
put_device we have to call class_device_put() due to the differences
in the the driver model device/class_device between 2.6.25 and
2.6.26. I can send a patch for 2.6.25 in a seperate mail.
Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
---
drivers/scsi/hosts.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 3690360..c6457bf 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -456,6 +456,10 @@ static int __scsi_host_match(struct device *dev, void *data)
*
* Return value:
* A pointer to located Scsi_Host or NULL.
+ *
+ * The caller must do a scsi_host_put() to drop the reference
+ * that scsi_host_get() took. The put_device() below dropped
+ * the reference from class_find_device().
**/
struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
{
@@ -463,9 +467,10 @@ struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
struct Scsi_Host *shost = ERR_PTR(-ENXIO);
cdev = class_find_device(&shost_class, &hostnum, __scsi_host_match);
- if (cdev)
+ if (cdev) {
shost = scsi_host_get(class_to_shost(cdev));
-
+ put_device(cdev);
+ }
return shost;
}
EXPORT_SYMBOL(scsi_host_lookup);
--
1.5.4.1
--
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