drivers/md/dm-hw-handler.h

   1 /*
   2  * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
   3  *
   4  * This file is released under the GPL.
   5  *
   6  * Multipath hardware handler registration.
   7  */
   8
   9 #ifndef DM_HW_HANDLER_H
  10 #define DM_HW_HANDLER_H
  11
  12 #include <linux/device-mapper.h>
  13
  14 #include "dm-mpath.h"
  15
  16 struct hw_handler_type;
  17 struct hw_handler {
  18         struct hw_handler_type *type;
  19         void *context;
  20 };
  21
  22 /*
  23  * Constructs a hardware handler object, takes custom arguments
  24  */
  25 /* Information about a hardware handler type */
  26 struct hw_handler_type {
  27         char *name;
  28         struct module *module;
  29
  30         int (*create) (struct hw_handler *handler, unsigned int argc,
  31                        char **argv);
  32         void (*destroy) (struct hw_handler *hwh);
  33
  34         void (*pg_init) (struct hw_handler *hwh, unsigned bypassed,
  35                          struct path *path);
  36         unsigned (*error) (struct hw_handler *hwh, struct bio *bio);
  37         int (*status) (struct hw_handler *hwh, status_type_t type,
  38                        char *result, unsigned int maxlen);
  39 };
  40
  41 /* Register a hardware handler */
  42 int dm_register_hw_handler(struct hw_handler_type *type);
  43
  44 /* Unregister a hardware handler */
  45 int dm_unregister_hw_handler(struct hw_handler_type *type);
  46
  47 /* Returns a registered hardware handler type */
  48 struct hw_handler_type *dm_get_hw_handler(const char *name);
  49
  50 /* Releases a hardware handler  */
  51 void dm_put_hw_handler(struct hw_handler_type *hwht);
  52
  53 /* Default err function */
  54 unsigned dm_scsi_err_handler(struct hw_handler *hwh, struct bio *bio);
  55
  56 /* Error flags for err and dm_pg_init_complete */
  57 #define MP_FAIL_PATH 1
  58 #define MP_BYPASS_PG 2
  59 #define MP_ERROR_IO  4  /* Don't retry this I/O */
  60
  61 #endif