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
  21 typedef struct PRManagerData {
  22     PRManager *pr_mgr;
  23     struct sg_io_hdr *hdr;
  24     int fd;
  25 } PRManagerData;
  26
  27 static int pr_manager_worker(void *opaque)
  28 {
  29     PRManagerData *data = opaque;
  30     PRManager *pr_mgr = data->pr_mgr;
  31     PRManagerClass *pr_mgr_class =
  32         PR_MANAGER_GET_CLASS(pr_mgr);
  33     struct sg_io_hdr *hdr = data->hdr;
  34     int fd = data->fd;
  35     int r;
  36
  37     g_free(data);
  38     trace_pr_manager_run(fd, hdr->cmdp[0], hdr->cmdp[1]);
  39
  40     /* The reference was taken in pr_manager_execute.  */
  41     r = pr_mgr_class->run(pr_mgr, fd, hdr);
  42     object_unref(OBJECT(pr_mgr));
  43     return r;
  44 }
  45
  46
  47 BlockAIOCB *pr_manager_execute(PRManager *pr_mgr,
  48                                AioContext *ctx, int fd,
  49                                struct sg_io_hdr *hdr,
  50                                BlockCompletionFunc *complete,
  51                                void *opaque)
  52 {
  53     PRManagerData *data = g_new(PRManagerData, 1);
  54     ThreadPool *pool = aio_get_thread_pool(ctx);
  55
  56     trace_pr_manager_execute(fd, hdr->cmdp[0], hdr->cmdp[1], opaque);
  57     data->pr_mgr = pr_mgr;
  58     data->fd = fd;
  59     data->hdr = hdr;
  60
  61     /* The matching object_unref is in pr_manager_worker.  */
  62     object_ref(OBJECT(pr_mgr));
  63     return thread_pool_submit_aio(pool, pr_manager_worker,
  64                                   data, complete, opaque);
  65 }
  66
  67 static const TypeInfo pr_manager_info = {
  68     .parent = TYPE_OBJECT,
  69     .name = TYPE_PR_MANAGER,
  70     .class_size = sizeof(PRManagerClass),
  71     .abstract = true,
  72     .interfaces = (InterfaceInfo[]) {
  73         { TYPE_USER_CREATABLE },
  74         { }
  75     }
  76 };
  77
  78 PRManager *pr_manager_lookup(const char *id, Error **errp)
  79 {
  80     Object *obj;
  81     PRManager *pr_mgr;
  82
  83     obj = object_resolve_path_component(object_get_objects_root(), id);
  84     if (!obj) {
  85         error_setg(errp, "No persistent reservation manager with id '%s'", id);
  86         return NULL;
  87     }
  88
  89     pr_mgr = (PRManager *)
  90         object_dynamic_cast(obj,
  91                             TYPE_PR_MANAGER);
  92     if (!pr_mgr) {
  93         error_setg(errp,
  94                    "Object with id '%s' is not a persistent reservation manager",
  95                    id);
  96         return NULL;
  97     }
  98
  99     return pr_mgr;
 100 }
 101
 102 static void
 103 pr_manager_register_types(void)
 104 {
 105     type_register_static(&pr_manager_info);
 106 }
 107
 108
 109 type_init(pr_manager_register_types);