Chandra Seetharaman wrote:
On Wed, 2008-05-14 at 16:43 +0200, Hannes Reinecke wrote:
Implement a 'dh_state' sdev attribute for dynamic device handler
manipulation. A read on the attribute will return the name of
the currently attached device handler or 'detached' if no handler
is attached.
The attribute allows the following strings to be written:
- The name of the device handler to be attached if the state is
'detached'.
- 'activate' to trigger path activation if a device handler
is attached.
- 'detach' to detach the currently attached device handler.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
All the sysfs functions can be grouped together. Helps in readability.
?? But I did ... Or thought so, anyway. Checking.
drivers/scsi/device_handler/scsi_dh.c | 88 +++++++++++++++++++++++++++++++++
1 files changed, 88 insertions(+), 0 deletions(-)
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index 55e5fd2..2dbf84b 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -54,6 +54,55 @@ static struct scsi_device_handler *get_device_handler(const char *name)
return found;
}
+static ssize_t
+store_dh_state(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct scsi_device *sdev = to_scsi_device(dev);
+ struct scsi_device_handler *scsi_dh;
+ int err = -EINVAL;
+
+ if (!sdev->scsi_dh_data) {
+ /*
+ * Attach to a device handler
+ */
+ if (!(scsi_dh = get_device_handler(buf)))
+ return err;
+ err = scsi_dh_handler_attach(sdev, scsi_dh);
+ } else {
+ /*
+ * Detach from a device handler
+ */
+ if (!strncmp(buf, "detach", 6)) {
+ err = scsi_dh_handler_detach(sdev);
+ } else if (!strncmp(buf, "activate", 8)) {
+ scsi_dh = sdev->scsi_dh_data->scsi_dh;
+
+ err = scsi_dh->activate(sdev);
+ }
+ }
+
+ return err<0?err:count;
+}
+
+static ssize_t
+show_dh_state(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct scsi_device *sdev = to_scsi_device(dev);
+ struct scsi_device_handler *scsi_dh;
+
+ if (!sdev->scsi_dh_data)
+ return snprintf(buf, 20, "detached\n");
+
+ scsi_dh = sdev->scsi_dh_data->scsi_dh;
we can use it directly instead of this variable ?
Yes.
+
+ return snprintf(buf, 20, "%s\n", scsi_dh->name);
+}
+
+static struct device_attribute scsi_dh_state_attr =
+ __ATTR(dh_state, S_IRUGO | S_IWUSR, show_dh_state,
+ store_dh_state);
+
/*
* scsi_dh_handler_attach - Attach a device handler to a device
* @sdev - SCSI device the device handler should attach to
@@ -115,9 +164,11 @@ static int scsi_dh_notifier(struct notifier_block *nb,
if (action == BUS_NOTIFY_ADD_DEVICE) {
scsi_dh_handler_attach(sdev, devinfo->handler);
+ device_create_file(dev, &scsi_dh_state_attr);
A later patch checks for the return status of scsi_dh_handler_attach(),
should be moved here.
Ok.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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