[3/4] block/dirty-bitmap: drop BdrvDirtyBitmap.mutex

mutex field is just a pointer to bs->dirty_bitmap_mutex, so no needs
to store it in BdrvDirtyBitmap when we have bs pointer in it (since
previous patch).

Drop mutex field. Constantly use bdrv_dirty_bitmaps_lock/unlock in
block/dirty-bitmap.c to make it more obvious that it's not per-bitmap
lock. Still, for simplicity, leave bdrv_dirty_bitmap_lock/unlock
functions as an external API.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/dirty-bitmap.c | 84 +++++++++++++++++++++-----------------------
 1 file changed, 41 insertions(+), 43 deletions(-)

On 9/16/19 10:19 AM, Vladimir Sementsov-Ogievskiy wrote:
> mutex field is just a pointer to bs->dirty_bitmap_mutex, so no needs
> to store it in BdrvDirtyBitmap when we have bs pointer in it (since
> previous patch).
> 
> Drop mutex field. Constantly use bdrv_dirty_bitmaps_lock/unlock in
> block/dirty-bitmap.c to make it more obvious that it's not per-bitmap
> lock. Still, for simplicity, leave bdrv_dirty_bitmap_lock/unlock
> functions as an external API.
> 

It's convenient, but I wish it had a better name because it still
implies a per-bitmap lock, which we've never had.

It's fine for now, this patch doesn't make it worse, of course.

> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Reviewed-by: John Snow <jsnow@redhat.com>

> ---
>  block/dirty-bitmap.c | 84 +++++++++++++++++++++-----------------------
>  1 file changed, 41 insertions(+), 43 deletions(-)
> 
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index f3dc7b3ca5..76a8e59e61 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -28,7 +28,6 @@
>  #include "block/blockjob.h"
>  
>  struct BdrvDirtyBitmap {
> -    QemuMutex *mutex;
>      BlockDriverState *bs;
>      HBitmap *bitmap;            /* Dirty bitmap implementation */
>      bool busy;                  /* Bitmap is busy, it can't be used via QMP */
> @@ -71,12 +70,12 @@ static inline void bdrv_dirty_bitmaps_unlock(BlockDriverState *bs)
>  
>  void bdrv_dirty_bitmap_lock(BdrvDirtyBitmap *bitmap)
>  {
> -    qemu_mutex_lock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>  }
>  
>  void bdrv_dirty_bitmap_unlock(BdrvDirtyBitmap *bitmap)
>  {
> -    qemu_mutex_unlock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  /* Called with BQL or dirty_bitmap lock taken.  */
> @@ -116,7 +115,6 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
>      }
>      bitmap = g_new0(BdrvDirtyBitmap, 1);
>      bitmap->bs = bs;
> -    bitmap->mutex = &bs->dirty_bitmap_mutex;
>      bitmap->bitmap = hbitmap_alloc(bitmap_size, ctz32(granularity));
>      bitmap->size = bitmap_size;
>      bitmap->name = g_strdup(name);
> @@ -150,9 +148,9 @@ static bool bdrv_dirty_bitmap_busy(const BdrvDirtyBitmap *bitmap)
>  
>  void bdrv_dirty_bitmap_set_busy(BdrvDirtyBitmap *bitmap, bool busy)
>  {
> -    qemu_mutex_lock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bitmap->busy = busy;
> -    qemu_mutex_unlock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  /* Called with BQL taken.  */
> @@ -277,10 +275,10 @@ void bdrv_enable_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap)
>  /* Called with BQL taken. */
>  void bdrv_dirty_bitmap_enable_successor(BdrvDirtyBitmap *bitmap)
>  {
> -    assert(bitmap->mutex == bitmap->successor->mutex);
> -    qemu_mutex_lock(bitmap->mutex);
> +    assert(bitmap->bs == bitmap->successor->bs);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bdrv_enable_dirty_bitmap_locked(bitmap->successor);
> -    qemu_mutex_unlock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  /* Called within bdrv_dirty_bitmap_lock..unlock and with BQL taken.  */
> @@ -360,9 +358,9 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BdrvDirtyBitmap *parent,
>  {
>      BdrvDirtyBitmap *ret;
>  
> -    qemu_mutex_lock(parent->mutex);
> +    bdrv_dirty_bitmaps_lock(parent->bs);
>      ret = bdrv_reclaim_dirty_bitmap_locked(parent, errp);
> -    qemu_mutex_unlock(parent->mutex);
> +    bdrv_dirty_bitmaps_unlock(parent->bs);
>  
>      return ret;
>  }
> @@ -434,16 +432,16 @@ void bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs,
>  
>  void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
>  {
> -    bdrv_dirty_bitmap_lock(bitmap);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bitmap->disabled = true;
> -    bdrv_dirty_bitmap_unlock(bitmap);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
>  {
> -    bdrv_dirty_bitmap_lock(bitmap);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bdrv_enable_dirty_bitmap_locked(bitmap);
> -    bdrv_dirty_bitmap_unlock(bitmap);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
> @@ -484,9 +482,9 @@ bool bdrv_dirty_bitmap_get_locked(BdrvDirtyBitmap *bitmap, int64_t offset)
>  bool bdrv_dirty_bitmap_get(BdrvDirtyBitmap *bitmap, int64_t offset)
>  {
>      bool ret;
> -    bdrv_dirty_bitmap_lock(bitmap);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      ret = bdrv_dirty_bitmap_get_locked(bitmap, offset);
> -    bdrv_dirty_bitmap_unlock(bitmap);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  
>      return ret;
>  }
> @@ -551,9 +549,9 @@ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
>  void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>                             int64_t offset, int64_t bytes)
>  {
> -    bdrv_dirty_bitmap_lock(bitmap);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bdrv_set_dirty_bitmap_locked(bitmap, offset, bytes);
> -    bdrv_dirty_bitmap_unlock(bitmap);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  /* Called within bdrv_dirty_bitmap_lock..unlock */
> @@ -567,15 +565,15 @@ void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
>  void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
>                               int64_t offset, int64_t bytes)
>  {
> -    bdrv_dirty_bitmap_lock(bitmap);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bdrv_reset_dirty_bitmap_locked(bitmap, offset, bytes);
> -    bdrv_dirty_bitmap_unlock(bitmap);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
>  {
>      assert(!bdrv_dirty_bitmap_readonly(bitmap));
> -    bdrv_dirty_bitmap_lock(bitmap);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      if (!out) {
>          hbitmap_reset_all(bitmap->bitmap);
>      } else {
> @@ -584,7 +582,7 @@ void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
>                                         hbitmap_granularity(backup));
>          *out = backup;
>      }
> -    bdrv_dirty_bitmap_unlock(bitmap);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup)
> @@ -679,9 +677,9 @@ bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap)
>  /* Called with BQL taken. */
>  void bdrv_dirty_bitmap_set_readonly(BdrvDirtyBitmap *bitmap, bool value)
>  {
> -    qemu_mutex_lock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bitmap->readonly = value;
> -    qemu_mutex_unlock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  bool bdrv_has_readonly_bitmaps(BlockDriverState *bs)
> @@ -699,27 +697,27 @@ bool bdrv_has_readonly_bitmaps(BlockDriverState *bs)
>  /* Called with BQL taken. */
>  void bdrv_dirty_bitmap_set_persistence(BdrvDirtyBitmap *bitmap, bool persistent)
>  {
> -    qemu_mutex_lock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bitmap->persistent = persistent;
> -    qemu_mutex_unlock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  /* Called with BQL taken. */
>  void bdrv_dirty_bitmap_set_inconsistent(BdrvDirtyBitmap *bitmap)
>  {
> -    qemu_mutex_lock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      assert(bitmap->persistent == true);
>      bitmap->inconsistent = true;
>      bitmap->disabled = true;
> -    qemu_mutex_unlock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  /* Called with BQL taken. */
>  void bdrv_dirty_bitmap_skip_store(BdrvDirtyBitmap *bitmap, bool skip)
>  {
> -    qemu_mutex_lock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_lock(bitmap->bs);
>      bitmap->skip_store = skip;
> -    qemu_mutex_unlock(bitmap->mutex);
> +    bdrv_dirty_bitmaps_unlock(bitmap->bs);
>  }
>  
>  bool bdrv_dirty_bitmap_get_persistence(BdrvDirtyBitmap *bitmap)
> @@ -779,9 +777,9 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
>  {
>      bool ret;
>  
> -    qemu_mutex_lock(dest->mutex);
> -    if (src->mutex != dest->mutex) {
> -        qemu_mutex_lock(src->mutex);
> +    bdrv_dirty_bitmaps_lock(dest->bs);
> +    if (src->bs != dest->bs) {
> +        bdrv_dirty_bitmaps_lock(src->bs);
>      }
>  
>      if (bdrv_dirty_bitmap_check(dest, BDRV_BITMAP_DEFAULT, errp)) {
> @@ -801,9 +799,9 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
>      assert(ret);
>  
>  out:
> -    qemu_mutex_unlock(dest->mutex);
> -    if (src->mutex != dest->mutex) {
> -        qemu_mutex_unlock(src->mutex);
> +    bdrv_dirty_bitmaps_unlock(dest->bs);
> +    if (src->bs != dest->bs) {
> +        bdrv_dirty_bitmaps_unlock(src->bs);
>      }
>  }
>  
> @@ -827,9 +825,9 @@ bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
>      assert(!bdrv_dirty_bitmap_inconsistent(src));
>  
>      if (lock) {
> -        qemu_mutex_lock(dest->mutex);
> -        if (src->mutex != dest->mutex) {
> -            qemu_mutex_lock(src->mutex);
> +        bdrv_dirty_bitmaps_lock(dest->bs);
> +        if (src->bs != dest->bs) {
> +            bdrv_dirty_bitmaps_lock(src->bs);
>          }
>      }
>  
> @@ -842,9 +840,9 @@ bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
>      }
>  
>      if (lock) {
> -        qemu_mutex_unlock(dest->mutex);
> -        if (src->mutex != dest->mutex) {
> -            qemu_mutex_unlock(src->mutex);
> +        bdrv_dirty_bitmaps_unlock(dest->bs);
> +        if (src->bs != dest->bs) {
> +            bdrv_dirty_bitmaps_unlock(src->bs);
>          }
>      }
>  
>