1 files changed, 144 insertions, 144 deletions

diff --git a/block/throttle-groups.c b/block/throttle-groups.c
index 890bfded3f..c8ed16ddf8 100644
--- a/block/throttle-groups.c
+++ b/block/throttle-groups.c
@@ -30,7 +30,7 @@
 #include "sysemu/qtest.h"
 
 /* The ThrottleGroup structure (with its ThrottleState) is shared
- * among different BlockBackends and it's independent from
+ * among different ThrottleGroupMembers and it's independent from
  * AioContext, so in order to use it from different threads it needs
  * its own locking.
  *
@@ -40,26 +40,26 @@
  * The whole ThrottleGroup structure is private and invisible to
  * outside users, that only use it through its ThrottleState.
  *
- * In addition to the ThrottleGroup structure, BlockBackendPublic has
+ * In addition to the ThrottleGroup structure, ThrottleGroupMember has
  * fields that need to be accessed by other members of the group and
  * therefore also need to be protected by this lock. Once a
- * BlockBackend is registered in a group those fields can be accessed
+ * ThrottleGroupMember is registered in a group those fields can be accessed
  * by other threads any time.
  *
  * Again, all this is handled internally and is mostly transparent to
  * the outside. The 'throttle_timers' field however has an additional
  * constraint because it may be temporarily invalid (see for example
  * blk_set_aio_context()). Therefore in this file a thread will
- * access some other BlockBackend's timers only after verifying that
- * that BlockBackend has throttled requests in the queue.
+ * access some other ThrottleGroupMember's timers only after verifying that
+ * that ThrottleGroupMember has throttled requests in the queue.
  */
 typedef struct ThrottleGroup {
     char *name; /* This is constant during the lifetime of the group */
 
     QemuMutex lock; /* This lock protects the following four fields */
     ThrottleState ts;
-    QLIST_HEAD(, BlockBackendPublic) head;
-    BlockBackend *tokens[2];
+    QLIST_HEAD(, ThrottleGroupMember) head;
+    ThrottleGroupMember *tokens[2];
     bool any_timer_armed[2];
     QEMUClockType clock_type;
 
@@ -140,114 +140,112 @@ void throttle_group_unref(ThrottleState *ts)
     qemu_mutex_unlock(&throttle_groups_lock);
 }
 
-/* Get the name from a BlockBackend's ThrottleGroup. The name (and the pointer)
+/* Get the name from a ThrottleGroupMember's group. The name (and the pointer)
  * is guaranteed to remain constant during the lifetime of the group.
  *
- * @blk:  a BlockBackend that is member of a throttling group
+ * @tgm:  a ThrottleGroupMember
  * @ret:  the name of the group.
  */
-const char *throttle_group_get_name(BlockBackend *blk)
+const char *throttle_group_get_name(ThrottleGroupMember *tgm)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleGroup *tg = container_of(blkp->throttle_state, ThrottleGroup, ts);
+    ThrottleGroup *tg = container_of(tgm->throttle_state, ThrottleGroup, ts);
     return tg->name;
 }
 
-/* Return the next BlockBackend in the round-robin sequence, simulating a
- * circular list.
+/* Return the next ThrottleGroupMember in the round-robin sequence, simulating
+ * a circular list.
  *
  * This assumes that tg->lock is held.
  *
- * @blk: the current BlockBackend
- * @ret: the next BlockBackend in the sequence
+ * @tgm: the current ThrottleGroupMember
+ * @ret: the next ThrottleGroupMember in the sequence
  */
-static BlockBackend *throttle_group_next_blk(BlockBackend *blk)
+static ThrottleGroupMember *throttle_group_next_tgm(ThrottleGroupMember *tgm)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleState *ts = blkp->throttle_state;
+    ThrottleState *ts = tgm->throttle_state;
     ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
-    BlockBackendPublic *next = QLIST_NEXT(blkp, round_robin);
+    ThrottleGroupMember *next = QLIST_NEXT(tgm, round_robin);
 
     if (!next) {
         next = QLIST_FIRST(&tg->head);
     }
 
-    return blk_by_public(next);
+    return next;
 }
 
 /*
- * Return whether a BlockBackend has pending requests.
+ * Return whether a ThrottleGroupMember has pending requests.
  *
  * This assumes that tg->lock is held.
  *
- * @blk: the BlockBackend
- * @is_write:  the type of operation (read/write)
- * @ret:       whether the BlockBackend has pending requests.
+ * @tgm:        the ThrottleGroupMember
+ * @is_write:   the type of operation (read/write)
+ * @ret:        whether the ThrottleGroupMember has pending requests.
  */
-static inline bool blk_has_pending_reqs(BlockBackend *blk,
+static inline bool tgm_has_pending_reqs(ThrottleGroupMember *tgm,
                                         bool is_write)
 {
-    const BlockBackendPublic *blkp = blk_get_public(blk);
-    return blkp->pending_reqs[is_write];
+    return tgm->pending_reqs[is_write];
 }
 
-/* Return the next BlockBackend in the round-robin sequence with pending I/O
- * requests.
+/* Return the next ThrottleGroupMember in the round-robin sequence with pending
+ * I/O requests.
  *
  * This assumes that tg->lock is held.
  *
- * @blk:       the current BlockBackend
+ * @tgm:       the current ThrottleGroupMember
  * @is_write:  the type of operation (read/write)
- * @ret:       the next BlockBackend with pending requests, or blk if there is
- *             none.
+ * @ret:       the next ThrottleGroupMember with pending requests, or tgm if
+ *             there is none.
  */
-static BlockBackend *next_throttle_token(BlockBackend *blk, bool is_write)
+static ThrottleGroupMember *next_throttle_token(ThrottleGroupMember *tgm,
+                                                bool is_write)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleGroup *tg = container_of(blkp->throttle_state, ThrottleGroup, ts);
-    BlockBackend *token, *start;
+    ThrottleState *ts = tgm->throttle_state;
+    ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
+    ThrottleGroupMember *token, *start;
 
     start = token = tg->tokens[is_write];
 
     /* get next bs round in round robin style */
-    token = throttle_group_next_blk(token);
-    while (token != start && !blk_has_pending_reqs(token, is_write)) {
-        token = throttle_group_next_blk(token);
+    token = throttle_group_next_tgm(token);
+    while (token != start && !tgm_has_pending_reqs(token, is_write)) {
+        token = throttle_group_next_tgm(token);
     }
 
     /* If no IO are queued for scheduling on the next round robin token
-     * then decide the token is the current bs because chances are
-     * the current bs get the current request queued.
+     * then decide the token is the current tgm because chances are
+     * the current tgm got the current request queued.
      */
-    if (token == start && !blk_has_pending_reqs(token, is_write)) {
-        token = blk;
+    if (token == start && !tgm_has_pending_reqs(token, is_write)) {
+        token = tgm;
     }
 
-    /* Either we return the original BB, or one with pending requests */
-    assert(token == blk || blk_has_pending_reqs(token, is_write));
+    /* Either we return the original TGM, or one with pending requests */
+    assert(token == tgm || tgm_has_pending_reqs(token, is_write));
 
     return token;
 }
 
-/* Check if the next I/O request for a BlockBackend needs to be throttled or
- * not. If there's no timer set in this group, set one and update the token
- * accordingly.
+/* Check if the next I/O request for a ThrottleGroupMember needs to be
+ * throttled or not. If there's no timer set in this group, set one and update
+ * the token accordingly.
  *
  * This assumes that tg->lock is held.
  *
- * @blk:        the current BlockBackend
+ * @tgm:        the current ThrottleGroupMember
  * @is_write:   the type of operation (read/write)
  * @ret:        whether the I/O request needs to be throttled or not
  */
-static bool throttle_group_schedule_timer(BlockBackend *blk, bool is_write)
+static bool throttle_group_schedule_timer(ThrottleGroupMember *tgm,
+                                          bool is_write)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleState *ts = blkp->throttle_state;
-    ThrottleTimers *tt = &blkp->throttle_timers;
+    ThrottleState *ts = tgm->throttle_state;
     ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
+    ThrottleTimers *tt = &tgm->throttle_timers;
     bool must_wait;
 
-    if (atomic_read(&blkp->io_limits_disabled)) {
+    if (atomic_read(&tgm->io_limits_disabled)) {
         return false;
     }
 
@@ -258,30 +256,29 @@ static bool throttle_group_schedule_timer(BlockBackend *blk, bool is_write)
 
     must_wait = throttle_schedule_timer(ts, tt, is_write);
 
-    /* If a timer just got armed, set blk as the current token */
+    /* If a timer just got armed, set tgm as the current token */
     if (must_wait) {
-        tg->tokens[is_write] = blk;
+        tg->tokens[is_write] = tgm;
         tg->any_timer_armed[is_write] = true;
     }
 
     return must_wait;
 }
 
-/* Start the next pending I/O request for a BlockBackend.  Return whether
+/* Start the next pending I/O request for a ThrottleGroupMember. Return whether
  * any request was actually pending.
  *
- * @blk:       the current BlockBackend
+ * @tgm:       the current ThrottleGroupMember
  * @is_write:  the type of operation (read/write)
  */
-static bool coroutine_fn throttle_group_co_restart_queue(BlockBackend *blk,
+static bool coroutine_fn throttle_group_co_restart_queue(ThrottleGroupMember *tgm,
                                                          bool is_write)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
     bool ret;
 
-    qemu_co_mutex_lock(&blkp->throttled_reqs_lock);
-    ret = qemu_co_queue_next(&blkp->throttled_reqs[is_write]);
-    qemu_co_mutex_unlock(&blkp->throttled_reqs_lock);
+    qemu_co_mutex_lock(&tgm->throttled_reqs_lock);
+    ret = qemu_co_queue_next(&tgm->throttled_reqs[is_write]);
+    qemu_co_mutex_unlock(&tgm->throttled_reqs_lock);
 
     return ret;
 }
@@ -290,19 +287,19 @@ static bool coroutine_fn throttle_group_co_restart_queue(BlockBackend *blk,
  *
  * This assumes that tg->lock is held.
  *
- * @blk:       the current BlockBackend
+ * @tgm:       the current ThrottleGroupMember
  * @is_write:  the type of operation (read/write)
  */
-static void schedule_next_request(BlockBackend *blk, bool is_write)
+static void schedule_next_request(ThrottleGroupMember *tgm, bool is_write)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleGroup *tg = container_of(blkp->throttle_state, ThrottleGroup, ts);
+    ThrottleState *ts = tgm->throttle_state;
+    ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
     bool must_wait;
-    BlockBackend *token;
+    ThrottleGroupMember *token;
 
     /* Check if there's any pending request to schedule next */
-    token = next_throttle_token(blk, is_write);
-    if (!blk_has_pending_reqs(token, is_write)) {
+    token = next_throttle_token(tgm, is_write);
+    if (!tgm_has_pending_reqs(token, is_write)) {
         return;
     }
 
@@ -311,12 +308,12 @@ static void schedule_next_request(BlockBackend *blk, bool is_write)
 
     /* If it doesn't have to wait, queue it for immediate execution */
     if (!must_wait) {
-        /* Give preference to requests from the current blk */
+        /* Give preference to requests from the current tgm */
         if (qemu_in_coroutine() &&
-            throttle_group_co_restart_queue(blk, is_write)) {
-            token = blk;
+            throttle_group_co_restart_queue(tgm, is_write)) {
+            token = tgm;
         } else {
-            ThrottleTimers *tt = &blk_get_public(token)->throttle_timers;
+            ThrottleTimers *tt = &token->throttle_timers;
             int64_t now = qemu_clock_get_ns(tg->clock_type);
             timer_mod(tt->timers[is_write], now);
             tg->any_timer_armed[is_write] = true;
@@ -329,76 +326,77 @@ static void schedule_next_request(BlockBackend *blk, bool is_write)
  * if necessary, and schedule the next request using a round robin
  * algorithm.
  *
- * @blk:       the current BlockBackend
+ * @tgm:       the current ThrottleGroupMember
  * @bytes:     the number of bytes for this I/O
  * @is_write:  the type of operation (read/write)
  */
-void coroutine_fn throttle_group_co_io_limits_intercept(BlockBackend *blk,
+void coroutine_fn throttle_group_co_io_limits_intercept(ThrottleGroupMember *tgm,
                                                         unsigned int bytes,
                                                         bool is_write)
 {
     bool must_wait;
-    BlockBackend *token;
-
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleGroup *tg = container_of(blkp->throttle_state, ThrottleGroup, ts);
+    ThrottleGroupMember *token;
+    ThrottleGroup *tg = container_of(tgm->throttle_state, ThrottleGroup, ts);
     qemu_mutex_lock(&tg->lock);
 
     /* First we check if this I/O has to be throttled. */
-    token = next_throttle_token(blk, is_write);
+    token = next_throttle_token(tgm, is_write);
     must_wait = throttle_group_schedule_timer(token, is_write);
 
     /* Wait if there's a timer set or queued requests of this type */
-    if (must_wait || blkp->pending_reqs[is_write]) {
-        blkp->pending_reqs[is_write]++;
+    if (must_wait || tgm->pending_reqs[is_write]) {
+        tgm->pending_reqs[is_write]++;
         qemu_mutex_unlock(&tg->lock);
-        qemu_co_mutex_lock(&blkp->throttled_reqs_lock);
-        qemu_co_queue_wait(&blkp->throttled_reqs[is_write],
-                           &blkp->throttled_reqs_lock);
-        qemu_co_mutex_unlock(&blkp->throttled_reqs_lock);
+        qemu_co_mutex_lock(&tgm->throttled_reqs_lock);
+        qemu_co_queue_wait(&tgm->throttled_reqs[is_write],
+                           &tgm->throttled_reqs_lock);
+        qemu_co_mutex_unlock(&tgm->throttled_reqs_lock);
         qemu_mutex_lock(&tg->lock);
-        blkp->pending_reqs[is_write]--;
+        tgm->pending_reqs[is_write]--;
     }
 
     /* The I/O will be executed, so do the accounting */
-    throttle_account(blkp->throttle_state, is_write, bytes);
+    throttle_account(tgm->throttle_state, is_write, bytes);
 
     /* Schedule the next request */
-    schedule_next_request(blk, is_write);
+    schedule_next_request(tgm, is_write);
 
     qemu_mutex_unlock(&tg->lock);
 }
 
 typedef struct {
-    BlockBackend *blk;
+    ThrottleGroupMember *tgm;
     bool is_write;
 } RestartData;
 
 static void coroutine_fn throttle_group_restart_queue_entry(void *opaque)
 {
     RestartData *data = opaque;
-    BlockBackend *blk = data->blk;
+    ThrottleGroupMember *tgm = data->tgm;
+    ThrottleState *ts = tgm->throttle_state;
+    ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
     bool is_write = data->is_write;
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleGroup *tg = container_of(blkp->throttle_state, ThrottleGroup, ts);
     bool empty_queue;
 
-    empty_queue = !throttle_group_co_restart_queue(blk, is_write);
+    empty_queue = !throttle_group_co_restart_queue(tgm, is_write);
 
     /* If the request queue was empty then we have to take care of
      * scheduling the next one */
     if (empty_queue) {
         qemu_mutex_lock(&tg->lock);
-        schedule_next_request(blk, is_write);
+        schedule_next_request(tgm, is_write);
         qemu_mutex_unlock(&tg->lock);
     }
 }
 
-static void throttle_group_restart_queue(BlockBackend *blk, bool is_write)
+static void throttle_group_restart_queue(ThrottleGroupMember *tgm, bool is_write)
 {
+    BlockBackendPublic *blkp = container_of(tgm, BlockBackendPublic,
+            throttle_group_member);
+    BlockBackend *blk = blk_by_public(blkp);
     Coroutine *co;
     RestartData rd = {
-        .blk = blk,
+        .tgm = tgm,
         .is_write = is_write
     };
 
@@ -406,13 +404,11 @@ static void throttle_group_restart_queue(BlockBackend *blk, bool is_write)
     aio_co_enter(blk_get_aio_context(blk), co);
 }
 
-void throttle_group_restart_blk(BlockBackend *blk)
+void throttle_group_restart_tgm(ThrottleGroupMember *tgm)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-
-    if (blkp->throttle_state) {
-        throttle_group_restart_queue(blk, 0);
-        throttle_group_restart_queue(blk, 1);
+    if (tgm->throttle_state) {
+        throttle_group_restart_queue(tgm, 0);
+        throttle_group_restart_queue(tgm, 1);
     }
 }
 
@@ -420,32 +416,30 @@ void throttle_group_restart_blk(BlockBackend *blk)
  * to throttle_config(), but guarantees atomicity within the
  * throttling group.
  *
- * @blk: a BlockBackend that is a member of the group
+ * @tgm:    a ThrottleGroupMember that is a member of the group
  * @cfg: the configuration to set
  */
-void throttle_group_config(BlockBackend *blk, ThrottleConfig *cfg)
+void throttle_group_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleState *ts = blkp->throttle_state;
+    ThrottleState *ts = tgm->throttle_state;
     ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
     qemu_mutex_lock(&tg->lock);
     throttle_config(ts, tg->clock_type, cfg);
     qemu_mutex_unlock(&tg->lock);
 
-    throttle_group_restart_blk(blk);
+    throttle_group_restart_tgm(tgm);
 }
 
 /* Get the throttle configuration from a particular group. Similar to
  * throttle_get_config(), but guarantees atomicity within the
  * throttling group.
  *
- * @blk: a BlockBackend that is a member of the group
+ * @tgm:    a ThrottleGroupMember that is a member of the group
  * @cfg: the configuration will be written here
  */
-void throttle_group_get_config(BlockBackend *blk, ThrottleConfig *cfg)
+void throttle_group_get_config(ThrottleGroupMember *tgm, ThrottleConfig *cfg)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleState *ts = blkp->throttle_state;
+    ThrottleState *ts = tgm->throttle_state;
     ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
     qemu_mutex_lock(&tg->lock);
     throttle_get_config(ts, cfg);
@@ -461,7 +455,8 @@ void throttle_group_get_config(BlockBackend *blk, ThrottleConfig *cfg)
 static void timer_cb(BlockBackend *blk, bool is_write)
 {
     BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleState *ts = blkp->throttle_state;
+    ThrottleGroupMember *tgm = &blkp->throttle_group_member;
+    ThrottleState *ts = tgm->throttle_state;
     ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
 
     /* The timer has just been fired, so we can update the flag */
@@ -470,7 +465,7 @@ static void timer_cb(BlockBackend *blk, bool is_write)
     qemu_mutex_unlock(&tg->lock);
 
     /* Run the request that was waiting for this timer */
-    throttle_group_restart_queue(blk, is_write);
+    throttle_group_restart_queue(tgm, is_write);
 }
 
 static void read_timer_cb(void *opaque)
@@ -483,32 +478,36 @@ static void write_timer_cb(void *opaque)
     timer_cb(opaque, true);
 }
 
-/* Register a BlockBackend in the throttling group, also initializing its
- * timers and updating its throttle_state pointer to point to it. If a
+/* Register a ThrottleGroupMember from the throttling group, also initializing
+ * its timers and updating its throttle_state pointer to point to it. If a
  * throttling group with that name does not exist yet, it will be created.
  *
- * @blk:       the BlockBackend to insert
+ * @tgm:       the ThrottleGroupMember to insert
  * @groupname: the name of the group
  */
-void throttle_group_register_blk(BlockBackend *blk, const char *groupname)
+void throttle_group_register_tgm(ThrottleGroupMember *tgm,
+                                 const char *groupname)
 {
     int i;
-    BlockBackendPublic *blkp = blk_get_public(blk);
+    BlockBackendPublic *blkp = container_of(tgm, BlockBackendPublic,
+            throttle_group_member);
+    BlockBackend *blk = blk_by_public(blkp);
     ThrottleState *ts = throttle_group_incref(groupname);
     ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
-    blkp->throttle_state = ts;
+
+    tgm->throttle_state = ts;
 
     qemu_mutex_lock(&tg->lock);
-    /* If the ThrottleGroup is new set this BlockBackend as the token */
+    /* If the ThrottleGroup is new set this ThrottleGroupMember as the token */
     for (i = 0; i < 2; i++) {
         if (!tg->tokens[i]) {
-            tg->tokens[i] = blk;
+            tg->tokens[i] = tgm;
         }
     }
 
-    QLIST_INSERT_HEAD(&tg->head, blkp, round_robin);
+    QLIST_INSERT_HEAD(&tg->head, tgm, round_robin);
 
-    throttle_timers_init(&blkp->throttle_timers,
+    throttle_timers_init(&tgm->throttle_timers,
                          blk_get_aio_context(blk),
                          tg->clock_type,
                          read_timer_cb,
@@ -518,45 +517,46 @@ void throttle_group_register_blk(BlockBackend *blk, const char *groupname)
     qemu_mutex_unlock(&tg->lock);
 }
 
-/* Unregister a BlockBackend from its group, removing it from the list,
+/* Unregister a ThrottleGroupMember from its group, removing it from the list,
  * destroying the timers and setting the throttle_state pointer to NULL.
  *
- * The BlockBackend must not have pending throttled requests, so the caller has
- * to drain them first.
+ * The ThrottleGroupMember must not have pending throttled requests, so the
+ * caller has to drain them first.
  *
  * The group will be destroyed if it's empty after this operation.
  *
- * @blk: the BlockBackend to remove
+ * @tgm the ThrottleGroupMember to remove
  */
-void throttle_group_unregister_blk(BlockBackend *blk)
+void throttle_group_unregister_tgm(ThrottleGroupMember *tgm)
 {
-    BlockBackendPublic *blkp = blk_get_public(blk);
-    ThrottleGroup *tg = container_of(blkp->throttle_state, ThrottleGroup, ts);
+    ThrottleState *ts = tgm->throttle_state;
+    ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
+    ThrottleGroupMember *token;
     int i;
 
-    assert(blkp->pending_reqs[0] == 0 && blkp->pending_reqs[1] == 0);
-    assert(qemu_co_queue_empty(&blkp->throttled_reqs[0]));
-    assert(qemu_co_queue_empty(&blkp->throttled_reqs[1]));
+    assert(tgm->pending_reqs[0] == 0 && tgm->pending_reqs[1] == 0);
+    assert(qemu_co_queue_empty(&tgm->throttled_reqs[0]));
+    assert(qemu_co_queue_empty(&tgm->throttled_reqs[1]));
 
     qemu_mutex_lock(&tg->lock);
     for (i = 0; i < 2; i++) {
-        if (tg->tokens[i] == blk) {
-            BlockBackend *token = throttle_group_next_blk(blk);
-            /* Take care of the case where this is the last blk in the group */
-            if (token == blk) {
+        if (tg->tokens[i] == tgm) {
+            token = throttle_group_next_tgm(tgm);
+            /* Take care of the case where this is the last tgm in the group */
+            if (token == tgm) {
                 token = NULL;
             }
             tg->tokens[i] = token;
         }
     }
 
-    /* remove the current blk from the list */
-    QLIST_REMOVE(blkp, round_robin);
-    throttle_timers_destroy(&blkp->throttle_timers);
+    /* remove the current tgm from the list */
+    QLIST_REMOVE(tgm, round_robin);
+    throttle_timers_destroy(&tgm->throttle_timers);
     qemu_mutex_unlock(&tg->lock);
 
     throttle_group_unref(&tg->ts);
-    blkp->throttle_state = NULL;
+    tgm->throttle_state = NULL;
 }
 
 static void throttle_groups_init(void)