[SCSI] libosd: osd_dev_info: Unique Identification of an OSD device
Define an osd_dev_info structure that Uniquely identifies an OSD
device lun on the network. The identification is built from unique
target attributes and is the same for all network/SAN machines.
osduld_info_lookup() - NEW
New API that will lookup an osd_dev by its osd_dev_info.
This is used by pNFS-objects for cross network global device
identification. And by exofs multy-device support, the device
info is specified in the on-disk exofs device table.
osduld_device_info() - NEW
Given an osd_dev handle returns its associated osd_dev_info.
The ULD fetches this information at startup and hangs it on
each OSD device. (This is a fast operation that can be called
at any condition)
osduld_device_same() - NEW
With a given osd_dev at one hand and an osd_dev_info
at another, we would like to know if they are the same
device.
Two osd_dev handles can be checked by:
osduld_device_same(od1, osduld_device_info(od2));
osd_auto_detect_ver() - REVISED
Now returns an osd_dev_info structure. Is only called once
by ULD as before. See added comments for how to use.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/include/scsi/osd_initiator.h b/include/scsi/osd_initiator.h
index 589e5f0..3ec346e 100644
--- a/include/scsi/osd_initiator.h
+++ b/include/scsi/osd_initiator.h
@@ -55,10 +55,24 @@
#endif
};
-/* Retrieve/return osd_dev(s) for use by Kernel clients */
-struct osd_dev *osduld_path_lookup(const char *dev_name); /*Use IS_ERR/ERR_PTR*/
+/* Unique Identification of an OSD device */
+struct osd_dev_info {
+ unsigned systemid_len;
+ u8 systemid[OSD_SYSTEMID_LEN];
+ unsigned osdname_len;
+ u8 *osdname;
+};
+
+/* Retrieve/return osd_dev(s) for use by Kernel clients
+ * Use IS_ERR/ERR_PTR on returned "osd_dev *".
+ */
+struct osd_dev *osduld_path_lookup(const char *dev_name);
+struct osd_dev *osduld_info_lookup(const struct osd_dev_info *odi);
void osduld_put_device(struct osd_dev *od);
+const struct osd_dev_info *osduld_device_info(struct osd_dev *od);
+bool osduld_device_same(struct osd_dev *od, const struct osd_dev_info *odi);
+
/* Add/remove test ioctls from external modules */
typedef int (do_test_fn)(struct osd_dev *od, unsigned cmd, unsigned long arg);
int osduld_register_test(unsigned ioctl, do_test_fn *do_test);
@@ -68,8 +82,24 @@
void osd_dev_init(struct osd_dev *od, struct scsi_device *scsi_device);
void osd_dev_fini(struct osd_dev *od);
-/* some hi level device operations */
-int osd_auto_detect_ver(struct osd_dev *od, void *caps); /* GFP_KERNEL */
+/**
+ * osd_auto_detect_ver - Detect the OSD version, return Unique Identification
+ *
+ * @od: OSD target lun handle
+ * @caps: Capabilities authorizing OSD root read attributes access
+ * @odi: Retrieved information uniquely identifying the osd target lun
+ * Note: odi->osdname must be kfreed by caller.
+ *
+ * Auto detects the OSD version of the OSD target and sets the @od
+ * accordingly. Meanwhile also returns the "system id" and "osd name" root
+ * attributes which uniquely identify the OSD target. This member is usually
+ * called by the ULD. ULD users should call osduld_device_info().
+ * This rutine allocates osd requests and memory at GFP_KERNEL level and might
+ * sleep.
+ */
+int osd_auto_detect_ver(struct osd_dev *od,
+ void *caps, struct osd_dev_info *odi);
+
static inline struct request_queue *osd_request_queue(struct osd_dev *od)
{
return od->scsi_device->request_queue;