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         struct mapped_device *md;
  20         void *context;
  21 };
  22
  23 /*
  24  * Constructs a hardware handler object, takes custom arguments
  25  */
  26 /* Information about a hardware handler type */
  27 struct hw_handler_type {
  28         char *name;
  29         struct module *module;
  30
  31         int (*create) (struct hw_handler *handler, unsigned int argc,
  32                        char **argv);
  33         void (*destroy) (struct hw_handler *hwh);
  34
  35         void (*pg_init) (struct hw_handler *hwh, unsigned bypassed,
  36                          struct dm_path *path);
  37         unsigned (*error) (struct hw_handler *hwh, struct bio *bio);
  38         int (*status) (struct hw_handler *hwh, status_type_t type,
  39                        char *result, unsigned int maxlen);
  40 };
  41
  42 /* Register a hardware handler */
  43 int dm_register_hw_handler(struct hw_handler_type *type);
  44
  45 /* Unregister a hardware handler */
  46 int dm_unregister_hw_handler(struct hw_handler_type *type);
  47
  48 /* Returns a registered hardware handler type */
  49 struct hw_handler_type *dm_get_hw_handler(const char *name);
  50
  51 /* Releases a hardware handler  */
  52 void dm_put_hw_handler(struct hw_handler_type *hwht);
  53
  54 /* Default err function */
  55 unsigned dm_scsi_err_handler(struct hw_handler *hwh, struct bio *bio);
  56
  57 /* Error flags for err and dm_pg_init_complete */
  58 #define MP_FAIL_PATH 1
  59 #define MP_BYPASS_PG 2
  60 #define MP_ERROR_IO  4  /* Don't retry this I/O */
  61 #define MP_RETRY 8
  62
  63 #endif