Re: [Qemu-block] [Qemu-devel] [PATCH v2] qcow2: Replace align_offset() with ROUND_UP()

[Philippe Mathieu-Daudé]

On 01/31/2018 07:21 AM, Alberto Garcia wrote:
> The align_offset() function is equivalent to the ROUND_UP() macro so
> there's no need to use the former. The ROUND_UP() name is also a bit
> more explicit.
> 
> This patch uses ROUND_UP() instead of the slower QEMU_ALIGN_UP()
> because align_offset() already requires that the second parameter is a
> power of two.
> 
> Signed-off-by: Alberto Garcia <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  block/qcow2-bitmap.c   |  4 ++--
>  block/qcow2-cluster.c  |  4 ++--
>  block/qcow2-refcount.c |  4 ++--
>  block/qcow2-snapshot.c | 10 +++++-----
>  block/qcow2.c          | 14 +++++++-------
>  block/qcow2.h          |  6 ------
>  6 files changed, 18 insertions(+), 24 deletions(-)
> 
> diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
> index efa10c6663..0a3803aa34 100644
> --- a/block/qcow2-bitmap.c
> +++ b/block/qcow2-bitmap.c
> @@ -413,8 +413,8 @@ static inline void 
> bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry)
>  
>  static inline int calc_dir_entry_size(size_t name_size, size_t 
> extra_data_size)
>  {
> -    return align_offset(sizeof(Qcow2BitmapDirEntry) +
> -                        name_size + extra_data_size, 8);
> +    int size = sizeof(Qcow2BitmapDirEntry) + name_size + extra_data_size;
> +    return ROUND_UP(size, 8);
>  }
>  
>  static inline int dir_entry_size(Qcow2BitmapDirEntry *entry)
> diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
> index a3fec27bf9..29d70e1f3e 100644
> --- a/block/qcow2-cluster.c
> +++ b/block/qcow2-cluster.c
> @@ -127,11 +127,11 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t 
> min_size,
>  
>      new_l1_size2 = sizeof(uint64_t) * new_l1_size;
>      new_l1_table = qemu_try_blockalign(bs->file->bs,
> -                                       align_offset(new_l1_size2, 512));
> +                                       ROUND_UP(new_l1_size2, 512));
>      if (new_l1_table == NULL) {
>          return -ENOMEM;
>      }
> -    memset(new_l1_table, 0, align_offset(new_l1_size2, 512));
> +    memset(new_l1_table, 0, ROUND_UP(new_l1_size2, 512));
>  
>      if (s->l1_size) {
>          memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
> diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
> index 92701ab7af..1d520615a8 100644
> --- a/block/qcow2-refcount.c
> +++ b/block/qcow2-refcount.c
> @@ -1202,7 +1202,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
>       * l1_table_offset when it is the current s->l1_table_offset! Be careful
>       * when changing this! */
>      if (l1_table_offset != s->l1_table_offset) {
> -        l1_table = g_try_malloc0(align_offset(l1_size2, 512));
> +        l1_table = g_try_malloc0(ROUND_UP(l1_size2, 512));
>          if (l1_size2 && l1_table == NULL) {
>              ret = -ENOMEM;
>              goto fail;
> @@ -2545,7 +2545,7 @@ int qcow2_check_metadata_overlap(BlockDriverState *bs, 
> int ign, int64_t offset,
>      }
>  
>      /* align range to test to cluster boundaries */
> -    size = align_offset(offset_into_cluster(s, offset) + size, 
> s->cluster_size);
> +    size = ROUND_UP(offset_into_cluster(s, offset) + size, s->cluster_size);
>      offset = start_of_cluster(s, offset);
>  
>      if ((chk & QCOW2_OL_ACTIVE_L1) && s->l1_size) {
> diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
> index 44243e0e95..cee25f582b 100644
> --- a/block/qcow2-snapshot.c
> +++ b/block/qcow2-snapshot.c
> @@ -66,7 +66,7 @@ int qcow2_read_snapshots(BlockDriverState *bs)
>  
>      for(i = 0; i < s->nb_snapshots; i++) {
>          /* Read statically sized part of the snapshot header */
> -        offset = align_offset(offset, 8);
> +        offset = ROUND_UP(offset, 8);
>          ret = bdrv_pread(bs->file, offset, &h, sizeof(h));
>          if (ret < 0) {
>              goto fail;
> @@ -155,7 +155,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
>      offset = 0;
>      for(i = 0; i < s->nb_snapshots; i++) {
>          sn = s->snapshots + i;
> -        offset = align_offset(offset, 8);
> +        offset = ROUND_UP(offset, 8);
>          offset += sizeof(h);
>          offset += sizeof(extra);
>          offset += strlen(sn->id_str);
> @@ -215,7 +215,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
>          assert(id_str_size <= UINT16_MAX && name_size <= UINT16_MAX);
>          h.id_str_size = cpu_to_be16(id_str_size);
>          h.name_size = cpu_to_be16(name_size);
> -        offset = align_offset(offset, 8);
> +        offset = ROUND_UP(offset, 8);
>  
>          ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h));
>          if (ret < 0) {
> @@ -441,7 +441,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, 
> QEMUSnapshotInfo *sn_info)
>      /* The VM state isn't needed any more in the active L1 table; in fact, it
>       * hurts by causing expensive COW for the next snapshot. */
>      qcow2_cluster_discard(bs, qcow2_vm_state_offset(s),
> -                          align_offset(sn->vm_state_size, s->cluster_size),
> +                          ROUND_UP(sn->vm_state_size, s->cluster_size),
>                            QCOW2_DISCARD_NEVER, false);
>  
>  #ifdef DEBUG_ALLOC
> @@ -710,7 +710,7 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
>      }
>      new_l1_bytes = sn->l1_size * sizeof(uint64_t);
>      new_l1_table = qemu_try_blockalign(bs->file->bs,
> -                                       align_offset(new_l1_bytes, 512));
> +                                       ROUND_UP(new_l1_bytes, 512));
>      if (new_l1_table == NULL) {
>          return -ENOMEM;
>      }
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 1f80961e1b..7f0fe00d49 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1354,7 +1354,7 @@ static int qcow2_do_open(BlockDriverState *bs, QDict 
> *options, int flags,
>  
>      if (s->l1_size > 0) {
>          s->l1_table = qemu_try_blockalign(bs->file->bs,
> -            align_offset(s->l1_size * sizeof(uint64_t), 512));
> +            ROUND_UP(s->l1_size * sizeof(uint64_t), 512));
>          if (s->l1_table == NULL) {
>              error_setg(errp, "Could not allocate L1 table");
>              ret = -ENOMEM;
> @@ -2615,19 +2615,19 @@ static int64_t qcow2_calc_prealloc_size(int64_t 
> total_size,
>  {
>      int64_t meta_size = 0;
>      uint64_t nl1e, nl2e;
> -    int64_t aligned_total_size = align_offset(total_size, cluster_size);
> +    int64_t aligned_total_size = ROUND_UP(total_size, cluster_size);
>  
>      /* header: 1 cluster */
>      meta_size += cluster_size;
>  
>      /* total size of L2 tables */
>      nl2e = aligned_total_size / cluster_size;
> -    nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
> +    nl2e = ROUND_UP(nl2e, cluster_size / sizeof(uint64_t));
>      meta_size += nl2e * sizeof(uint64_t);
>  
>      /* total size of L1 tables */
>      nl1e = nl2e * sizeof(uint64_t) / cluster_size;
> -    nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t));
> +    nl1e = ROUND_UP(nl1e, cluster_size / sizeof(uint64_t));
>      meta_size += nl1e * sizeof(uint64_t);
>  
>      /* total size of refcount table and blocks */
> @@ -3681,8 +3681,8 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, 
> BlockDriverState *in_bs,
>      has_backing_file = !!optstr;
>      g_free(optstr);
>  
> -    virtual_size = align_offset(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 
> 0),
> -                                cluster_size);
> +    virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
> +    virtual_size = ROUND_UP(virtual_size, cluster_size);
>  
>      /* Check that virtual disk size is valid */
>      l2_tables = DIV_ROUND_UP(virtual_size / cluster_size,
> @@ -3702,7 +3702,7 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, 
> BlockDriverState *in_bs,
>              goto err;
>          }
>  
> -        virtual_size = align_offset(ssize, cluster_size);
> +        virtual_size = ROUND_UP(ssize, cluster_size);
>  
>          if (has_backing_file) {
>              /* We don't how much of the backing chain is shared by the input
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 46c8cf44ec..33d2eb0ead 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -468,12 +468,6 @@ static inline int offset_to_l2_index(BDRVQcow2State *s, 
> int64_t offset)
>      return (offset >> s->cluster_bits) & (s->l2_size - 1);
>  }
>  
> -static inline int64_t align_offset(int64_t offset, int n)
> -{
> -    offset = (offset + n - 1) & ~(n - 1);
> -    return offset;
> -}
> -
>  static inline int64_t qcow2_vm_state_offset(BDRVQcow2State *s)
>  {
>      return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
>