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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
parent21fab1d0595eacf781705ec3509012a28f298245 (diff)
downloadop-kernel-dev-18ee70c9d7b2dcd312a1f8c6536841e7c0fea5ca.zip
op-kernel-dev-18ee70c9d7b2dcd312a1f8c6536841e7c0fea5ca.tar.gz
[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>
-rw-r--r--drivers/scsi/device_handler/scsi_dh.c33
-rw-r--r--include/scsi/scsi_device.h1
-rw-r--r--include/scsi/scsi_dh.h5
3 files changed, 39 insertions, 0 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index 53a7385..3ee1cbc 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.
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 1f3a4c8..9af48cb 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -187,6 +187,7 @@ struct scsi_device_handler {
void (*detach)(struct scsi_device *);
int (*activate)(struct scsi_device *);
int (*prep_fn)(struct scsi_device *, struct request *);
+ int (*set_params)(struct scsi_device *, const char *);
};
struct scsi_dh_data {
diff --git a/include/scsi/scsi_dh.h b/include/scsi/scsi_dh.h
index 33efce2..ff24074 100644
--- a/include/scsi/scsi_dh.h
+++ b/include/scsi/scsi_dh.h
@@ -60,6 +60,7 @@ extern int scsi_dh_activate(struct request_queue *);
extern int scsi_dh_handler_exist(const char *);
extern int scsi_dh_attach(struct request_queue *, const char *);
extern void scsi_dh_detach(struct request_queue *);
+extern int scsi_dh_set_params(struct request_queue *, const char *);
#else
static inline int scsi_dh_activate(struct request_queue *req)
{
@@ -77,4 +78,8 @@ static inline void scsi_dh_detach(struct request_queue *q)
{
return;
}
+static inline int scsi_dh_set_params(struct request_queue *req, const char *params)
+{
+ return -SCSI_DH_NOSYS;
+}
#endif
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