linux/include/scsi/scsi_dh.h
Chandra Seetharaman 18ee70c9d7 [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>
2009-08-22 17:52:14 -05:00

85 lines
2.5 KiB
C

/*
* Header file for SCSI device handler infrastruture.
*
* Modified version of patches posted by Mike Christie <michaelc@cs.wisc.edu>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright IBM Corporation, 2007
* Authors:
* Chandra Seetharaman <sekharan@us.ibm.com>
* Mike Anderson <andmike@linux.vnet.ibm.com>
*/
#include <scsi/scsi_device.h>
enum {
SCSI_DH_OK = 0,
/*
* device errors
*/
SCSI_DH_DEV_FAILED, /* generic device error */
SCSI_DH_DEV_TEMP_BUSY,
SCSI_DH_DEV_UNSUPP, /* device handler not supported */
SCSI_DH_DEVICE_MAX, /* max device blkerr definition */
/*
* transport errors
*/
SCSI_DH_NOTCONN = SCSI_DH_DEVICE_MAX + 1,
SCSI_DH_CONN_FAILURE,
SCSI_DH_TRANSPORT_MAX, /* max transport blkerr definition */
/*
* driver and generic errors
*/
SCSI_DH_IO = SCSI_DH_TRANSPORT_MAX + 1, /* generic error */
SCSI_DH_INVALID_IO,
SCSI_DH_RETRY, /* retry the req, but not immediately */
SCSI_DH_IMM_RETRY, /* immediately retry the req */
SCSI_DH_TIMED_OUT,
SCSI_DH_RES_TEMP_UNAVAIL,
SCSI_DH_DEV_OFFLINED,
SCSI_DH_NOSYS,
SCSI_DH_DRIVER_MAX,
};
#if defined(CONFIG_SCSI_DH) || defined(CONFIG_SCSI_DH_MODULE)
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)
{
return 0;
}
static inline int scsi_dh_handler_exist(const char *name)
{
return 0;
}
static inline int scsi_dh_attach(struct request_queue *req, const char *name)
{
return SCSI_DH_NOSYS;
}
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