[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

[dm-devel] Re: [PATCH 2/7] scsi_dh: Add 'dh_state' sysfs attribute



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 suse de>
---

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 suse de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]