[Qemu-devel] [PATCH v3 16/16] block: Remove bdrv_swap()

[Kevin Wolf <kwolf@redhat.com>]

bdrv_swap() is unused now. Remove it and all functions that have
no other users than bdrv_swap(). In particular, this removes the
.bdrv_rebind callbacks from block drivers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
---
 block.c                   | 155 +---------------------------------------------
 block/qed.c               |   7 ---
 block/vvfat.c             |   7 ---
 include/block/block_int.h |   1 -
 include/qemu/queue.h      |   6 --
 5 files changed, 1 insertion(+), 175 deletions(-)

diff --git a/block.c b/block.c
index 7c66d3e..f38146e 100644
--- a/block.c
+++ b/block.c
@@ -1981,15 +1981,7 @@ void bdrv_make_anon(BlockDriverState *bs)
     bs->node_name[0] = '\0';
 }
 
-static void bdrv_rebind(BlockDriverState *bs)
-{
-    if (bs->drv && bs->drv->bdrv_rebind) {
-        bs->drv->bdrv_rebind(bs);
-    }
-}
-
-/* Fields that need to stay with the top-level BDS, no matter whether the
- * address of the top-level BDS stays the same or not. */
+/* Fields that need to stay with the top-level BDS */
 static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
                                      BlockDriverState *bs_src)
 {
@@ -2013,151 +2005,6 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
     bs_dest->dirty_bitmaps      = bs_src->dirty_bitmaps;
 }
 
-/* Fields that only need to be swapped if the contents of BDSes is swapped
- * rather than pointers being changed in the parents, and throttling fields
- * because only bdrv_swap() messes with internals of throttling. */
-static void bdrv_move_reference_fields(BlockDriverState *bs_dest,
-                                       BlockDriverState *bs_src)
-{
-    /* i/o throttled req */
-    bs_dest->throttle_state     = bs_src->throttle_state,
-    bs_dest->io_limits_enabled  = bs_src->io_limits_enabled;
-    bs_dest->pending_reqs[0]    = bs_src->pending_reqs[0];
-    bs_dest->pending_reqs[1]    = bs_src->pending_reqs[1];
-    bs_dest->throttled_reqs[0]  = bs_src->throttled_reqs[0];
-    bs_dest->throttled_reqs[1]  = bs_src->throttled_reqs[1];
-    memcpy(&bs_dest->round_robin,
-           &bs_src->round_robin,
-           sizeof(bs_dest->round_robin));
-    memcpy(&bs_dest->throttle_timers,
-           &bs_src->throttle_timers,
-           sizeof(ThrottleTimers));
-
-    /* reference count */
-    bs_dest->refcnt             = bs_src->refcnt;
-
-    /* job */
-    bs_dest->job                = bs_src->job;
-
-    /* keep the same entry in bdrv_states */
-    bs_dest->device_list = bs_src->device_list;
-    bs_dest->blk = bs_src->blk;
-    bs_dest->parents = bs_src->parents;
-
-    memcpy(bs_dest->op_blockers, bs_src->op_blockers,
-           sizeof(bs_dest->op_blockers));
-}
-
-/*
- * Swap bs contents for two image chains while they are live,
- * while keeping required fields on the BlockDriverState that is
- * actually attached to a device.
- *
- * This will modify the BlockDriverState fields, and swap contents
- * between bs_new and bs_old. Both bs_new and bs_old are modified.
- *
- * bs_new must not be attached to a BlockBackend.
- *
- * This function does not create any image files.
- */
-void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old)
-{
-    BlockDriverState tmp;
-    BdrvChild *child;
-
-    bdrv_drain(bs_new);
-    bdrv_drain(bs_old);
-
-    /* The code needs to swap the node_name but simply swapping node_list won't
-     * work so first remove the nodes from the graph list, do the swap then
-     * insert them back if needed.
-     */
-    if (bs_new->node_name[0] != '\0') {
-        QTAILQ_REMOVE(&graph_bdrv_states, bs_new, node_list);
-    }
-    if (bs_old->node_name[0] != '\0') {
-        QTAILQ_REMOVE(&graph_bdrv_states, bs_old, node_list);
-    }
-
-    /* If the BlockDriverState is part of a throttling group acquire
-     * its lock since we're going to mess with the protected fields.
-     * Otherwise there's no need to worry since no one else can touch
-     * them. */
-    if (bs_old->throttle_state) {
-        throttle_group_lock(bs_old);
-    }
-
-    /* bs_new must be unattached and shouldn't have anything fancy enabled */
-    assert(!bs_new->blk);
-    assert(QLIST_EMPTY(&bs_new->dirty_bitmaps));
-    assert(bs_new->job == NULL);
-    assert(bs_new->io_limits_enabled == false);
-    assert(bs_new->throttle_state == NULL);
-    assert(!throttle_timers_are_initialized(&bs_new->throttle_timers));
-
-    tmp = *bs_new;
-    *bs_new = *bs_old;
-    *bs_old = tmp;
-
-    /* there are some fields that should not be swapped, move them back */
-    bdrv_move_feature_fields(&tmp, bs_old);
-    bdrv_move_feature_fields(bs_old, bs_new);
-    bdrv_move_feature_fields(bs_new, &tmp);
-
-    bdrv_move_reference_fields(&tmp, bs_old);
-    bdrv_move_reference_fields(bs_old, bs_new);
-    bdrv_move_reference_fields(bs_new, &tmp);
-
-    /* bs_new must remain unattached */
-    assert(!bs_new->blk);
-
-    /* Check a few fields that should remain attached to the device */
-    assert(bs_new->job == NULL);
-    assert(bs_new->io_limits_enabled == false);
-    assert(bs_new->throttle_state == NULL);
-    assert(!throttle_timers_are_initialized(&bs_new->throttle_timers));
-
-    /* Release the ThrottleGroup lock */
-    if (bs_old->throttle_state) {
-        throttle_group_unlock(bs_old);
-    }
-
-    /* insert the nodes back into the graph node list if needed */
-    if (bs_new->node_name[0] != '\0') {
-        QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs_new, node_list);
-    }
-    if (bs_old->node_name[0] != '\0') {
-        QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs_old, node_list);
-    }
-
-    /*
-     * Update lh_first.le_prev for non-empty lists.
-     *
-     * The head of the op blocker list doesn't change because it is moved back
-     * in bdrv_move_feature_fields().
-     */
-    assert(QLIST_EMPTY(&bs_old->tracked_requests));
-    assert(QLIST_EMPTY(&bs_new->tracked_requests));
-
-    QLIST_FIX_HEAD_PTR(&bs_new->children, next);
-    QLIST_FIX_HEAD_PTR(&bs_old->children, next);
-
-    /* Update references in bs->opaque and children */
-    QLIST_FOREACH(child, &bs_old->children, next) {
-        if (child->bs->inherits_from == bs_new) {
-            child->bs->inherits_from = bs_old;
-        }
-    }
-    QLIST_FOREACH(child, &bs_new->children, next) {
-        if (child->bs->inherits_from == bs_old) {
-            child->bs->inherits_from = bs_new;
-        }
-    }
-
-    bdrv_rebind(bs_new);
-    bdrv_rebind(bs_old);
-}
-
 static void change_parent_backing_link(BlockDriverState *from,
                                        BlockDriverState *to)
 {
diff --git a/block/qed.c b/block/qed.c
index 0af81dc..5ea05d4 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -354,12 +354,6 @@ static void qed_cancel_need_check_timer(BDRVQEDState *s)
     timer_del(s->need_check_timer);
 }
 
-static void bdrv_qed_rebind(BlockDriverState *bs)
-{
-    BDRVQEDState *s = bs->opaque;
-    s->bs = bs;
-}
-
 static void bdrv_qed_detach_aio_context(BlockDriverState *bs)
 {
     BDRVQEDState *s = bs->opaque;
@@ -1664,7 +1658,6 @@ static BlockDriver bdrv_qed = {
     .supports_backing         = true,
 
     .bdrv_probe               = bdrv_qed_probe,
-    .bdrv_rebind              = bdrv_qed_rebind,
     .bdrv_open                = bdrv_qed_open,
     .bdrv_close               = bdrv_qed_close,
     .bdrv_reopen_prepare      = bdrv_qed_reopen_prepare,
diff --git a/block/vvfat.c b/block/vvfat.c
index b41055a..b184eca 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -985,12 +985,6 @@ static BDRVVVFATState *vvv = NULL;
 static int enable_write_target(BDRVVVFATState *s, Error **errp);
 static int is_consistent(BDRVVVFATState *s);
 
-static void vvfat_rebind(BlockDriverState *bs)
-{
-    BDRVVVFATState *s = bs->opaque;
-    s->bs = bs;
-}
-
 static QemuOptsList runtime_opts = {
     .name = "vvfat",
     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
@@ -3012,7 +3006,6 @@ static BlockDriver bdrv_vvfat = {
     .bdrv_parse_filename    = vvfat_parse_filename,
     .bdrv_file_open         = vvfat_open,
     .bdrv_close             = vvfat_close,
-    .bdrv_rebind            = vvfat_rebind,
 
     .bdrv_read              = vvfat_co_read,
     .bdrv_write             = vvfat_co_write,
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 52ea7c0..c0e6513 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -122,7 +122,6 @@ struct BlockDriver {
     int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num,
                       const uint8_t *buf, int nb_sectors);
     void (*bdrv_close)(BlockDriverState *bs);
-    void (*bdrv_rebind)(BlockDriverState *bs);
     int (*bdrv_create)(const char *filename, QemuOpts *opts, Error **errp);
     int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
     int (*bdrv_make_empty)(BlockDriverState *bs);
diff --git a/include/qemu/queue.h b/include/qemu/queue.h
index a8d3cb8..f781aa2 100644
--- a/include/qemu/queue.h
+++ b/include/qemu/queue.h
@@ -117,12 +117,6 @@ struct {                                                                \
         }                                                               \
 } while (/*CONSTCOND*/0)
 
-#define QLIST_FIX_HEAD_PTR(head, field) do {                            \
-        if ((head)->lh_first != NULL) {                                 \
-            (head)->lh_first->field.le_prev = &(head)->lh_first;        \
-        }                                                               \
-} while (/*CONSTCOND*/0)
-
 #define QLIST_INSERT_AFTER(listelm, elm, field) do {                    \
         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
                 (listelm)->field.le_next->field.le_prev =               \
-- 
1.8.3.1