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authorChandra Seetharaman <sekharan@us.ibm.com>2009-08-03 12:42:33 -0700
committerJames Bottomley <James.Bottomley@suse.de>2009-08-22 17:52:14 -0500
commit18ee70c9d7b2dcd312a1f8c6536841e7c0fea5ca (patch)
treefc147f1704a72f2e79b4b2b4e3aedee95b26f601 /drivers/scsi/device_handler
parent21fab1d0595eacf781705ec3509012a28f298245 (diff)
[SCSI] scsi_dh: add the interface scsi_dh_set_params()
When we moved the device handler functionality from dm layer to SCSI layer we dropped the parameter functionality. This path adds an interface to scsi dh layer to set device handler parameters. Basically, multipath layer need to create a string with all the parameters and call scsi_dh_set_params() after it called scsi_dh_attach() on a device. If a device handler provides such an interface it will handle the parameters as it expects them. Reported-by: Eddie Williams <Eddie.Williams@steeleye.com> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Tested-by: Eddie Williams <Eddie.Williams@steeleye.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/device_handler')
-rw-r--r--drivers/scsi/device_handler/scsi_dh.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index 53a7385e1b4..3ee1cbc8947 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -452,6 +452,39 @@ int scsi_dh_activate(struct request_queue *q)
EXPORT_SYMBOL_GPL(scsi_dh_activate);
/*
+ * scsi_dh_set_params - set the parameters for the device as per the
+ * string specified in params.
+ * @q - Request queue that is associated with the scsi_device for
+ * which the parameters to be set.
+ * @params - parameters in the following format
+ * "no_of_params\0param1\0param2\0param3\0...\0"
+ * for example, string for 2 parameters with value 10 and 21
+ * is specified as "2\010\021\0".
+ */
+int scsi_dh_set_params(struct request_queue *q, const char *params)
+{
+ int err = -SCSI_DH_NOSYS;
+ unsigned long flags;
+ struct scsi_device *sdev;
+ struct scsi_device_handler *scsi_dh = NULL;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ sdev = q->queuedata;
+ if (sdev && sdev->scsi_dh_data)
+ scsi_dh = sdev->scsi_dh_data->scsi_dh;
+ if (scsi_dh && scsi_dh->set_params && get_device(&sdev->sdev_gendev))
+ err = 0;
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ if (err)
+ return err;
+ err = scsi_dh->set_params(sdev, params);
+ put_device(&sdev->sdev_gendev);
+ return err;
+}
+EXPORT_SYMBOL_GPL(scsi_dh_set_params);
+
+/*
* scsi_dh_handler_exist - Return TRUE(1) if a device handler exists for
* the given name. FALSE(0) otherwise.
* @name - name of the device handler.