scsi/pr-manager.c

   1 /*
   2  * Persistent reservation manager abstract class
   3  *
   4  * Copyright (c) 2017 Red Hat, Inc.
   5  *
   6  * Author: Paolo Bonzini <pbonzini@redhat.com>
   7  *
   8  * This code is licensed under the LGPL.
   9  *
  10  */
  11
  12 #include "qemu/osdep.h"
  13 #include <scsi/sg.h>
  14
  15 #include "qapi/error.h"
  16 #include "block/aio.h"
  17 #include "block/thread-pool.h"
  18 #include "scsi/pr-manager.h"
  19 #include "trace.h"
  20 #include "qapi/qapi-types-block.h"
  21 #include "qapi/qapi-commands-block.h"
  22
  23 #define PR_MANAGER_PATH     "/objects"
  24
  25 typedef struct PRManagerData {
  26     PRManager *pr_mgr;
  27     struct sg_io_hdr *hdr;
  28     int fd;
  29 } PRManagerData;
  30
  31 static int pr_manager_worker(void *opaque)
  32 {
  33     PRManagerData *data = opaque;
  34     PRManager *pr_mgr = data->pr_mgr;
  35     PRManagerClass *pr_mgr_class =
  36         PR_MANAGER_GET_CLASS(pr_mgr);
  37     struct sg_io_hdr *hdr = data->hdr;
  38     int fd = data->fd;
  39     int r;
  40
  41     g_free(data);
  42     trace_pr_manager_run(fd, hdr->cmdp[0], hdr->cmdp[1]);
  43
  44     /* The reference was taken in pr_manager_execute.  */
  45     r = pr_mgr_class->run(pr_mgr, fd, hdr);
  46     object_unref(OBJECT(pr_mgr));
  47     return r;
  48 }
  49
  50
  51 BlockAIOCB *pr_manager_execute(PRManager *pr_mgr,
  52                                AioContext *ctx, int fd,
  53                                struct sg_io_hdr *hdr,
  54                                BlockCompletionFunc *complete,
  55                                void *opaque)
  56 {
  57     PRManagerData *data = g_new(PRManagerData, 1);
  58     ThreadPool *pool = aio_get_thread_pool(ctx);
  59
  60     trace_pr_manager_execute(fd, hdr->cmdp[0], hdr->cmdp[1], opaque);
  61     data->pr_mgr = pr_mgr;
  62     data->fd = fd;
  63     data->hdr = hdr;
  64
  65     /* The matching object_unref is in pr_manager_worker.  */
  66     object_ref(OBJECT(pr_mgr));
  67     return thread_pool_submit_aio(pool, pr_manager_worker,
  68                                   data, complete, opaque);
  69 }
  70
  71 bool pr_manager_is_connected(PRManager *pr_mgr)
  72 {
  73     PRManagerClass *pr_mgr_class =
  74         PR_MANAGER_GET_CLASS(pr_mgr);
  75
  76     return !pr_mgr_class->is_connected || pr_mgr_class->is_connected(pr_mgr);
  77 }
  78
  79 static const TypeInfo pr_manager_info = {
  80     .parent = TYPE_OBJECT,
  81     .name = TYPE_PR_MANAGER,
  82     .class_size = sizeof(PRManagerClass),
  83     .abstract = true,
  84     .interfaces = (InterfaceInfo[]) {
  85         { TYPE_USER_CREATABLE },
  86         { }
  87     }
  88 };
  89
  90 PRManager *pr_manager_lookup(const char *id, Error **errp)
  91 {
  92     Object *obj;
  93     PRManager *pr_mgr;
  94
  95     obj = object_resolve_path_component(object_get_objects_root(), id);
  96     if (!obj) {
  97         error_setg(errp, "No persistent reservation manager with id '%s'", id);
  98         return NULL;
  99     }
 100
 101     pr_mgr = (PRManager *)
 102         object_dynamic_cast(obj,
 103                             TYPE_PR_MANAGER);
 104     if (!pr_mgr) {
 105         error_setg(errp,
 106                    "Object with id '%s' is not a persistent reservation manager",
 107                    id);
 108         return NULL;
 109     }
 110
 111     return pr_mgr;
 112 }
 113
 114 static void
 115 pr_manager_register_types(void)
 116 {
 117     type_register_static(&pr_manager_info);
 118 }
 119
 120 static int query_one_pr_manager(Object *object, void *opaque)
 121 {
 122     PRManagerInfoList ***prev = opaque;
 123     PRManagerInfoList *elem;
 124     PRManagerInfo *info;
 125     PRManager *pr_mgr;
 126
 127     pr_mgr = (PRManager *)object_dynamic_cast(object, TYPE_PR_MANAGER);
 128     if (!pr_mgr) {
 129         return 0;
 130     }
 131
 132     elem = g_new0(PRManagerInfoList, 1);
 133     info = g_new0(PRManagerInfo, 1);
 134     info->id = object_get_canonical_path_component(object);
 135     info->connected = pr_manager_is_connected(pr_mgr);
 136     elem->value = info;
 137     elem->next = NULL;
 138
 139     **prev = elem;
 140     *prev = &elem->next;
 141     return 0;
 142 }
 143
 144 PRManagerInfoList *qmp_query_pr_managers(Error **errp)
 145 {
 146     PRManagerInfoList *head = NULL;
 147     PRManagerInfoList **prev = &head;
 148     Object *container = container_get(object_get_root(), PR_MANAGER_PATH);
 149
 150     object_child_foreach(container, query_one_pr_manager, &prev);
 151     return head;
 152 }
 153
 154 type_init(pr_manager_register_types);