Re: [Qemu-devel] [PATCH v2 13/17] qcow: make encrypt_sectors encrypt in place

[Eric Blake <eblake@redhat.com>]

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On 01/20/2016 10:38 AM, Daniel P. Berrange wrote:
> Instead of requiring separate input/output buffers for
> encrypting data, change encrypt_sectors() to assume
> use of a single buffer, encrypting in place. One current
> caller all uses the same buffer for input/output already
> and the other two callers are easily converted todo so.

s/todo/to do/

> 
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  block/qcow.c | 31 ++++++++++---------------------
>  1 file changed, 10 insertions(+), 21 deletions(-)
> 

> @@ -453,13 +447,12 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
>                      uint64_t start_sect;
>                      assert(s->cipher);
>                      start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
> -                    memset(s->cluster_data + 512, 0x00, 512);
> +                    memset(s->cluster_data, 0x00, 512);
>                      for(i = 0; i < s->cluster_sectors; i++) {

As long as you're touching near here, is it worth adding a space before '('?

> @@ -672,7 +665,6 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
>      BDRVQcowState *s = bs->opaque;
>      int index_in_cluster;
>      uint64_t cluster_offset;
> -    const uint8_t *src_buf;
>      int ret = 0, n;
>      uint8_t *cluster_data = NULL;
>      struct iovec hd_iov;
> @@ -715,18 +707,15 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
>              if (!cluster_data) {
>                  cluster_data = g_malloc0(s->cluster_size);
>              }
> -            if (encrypt_sectors(s, sector_num, cluster_data, buf,
> +            if (encrypt_sectors(s, sector_num, buf,
>                                  n, true, &err) < 0) {
>                  error_free(err);
>                  ret = -EIO;
>                  break;
>              }
> -            src_buf = cluster_data;

cluster_data is now unused; you've got a wasted g_malloc0() here and
g_free() later on.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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