Re: [Qemu-devel] [PATCH 3/3] block: Drop some superfluous casts from void *

[Markus Armbruster <armbru@redhat.com>]

Max Reitz <mreitz@redhat.com> writes:

> On 30.05.2014 18:30, Markus Armbruster wrote:
>> They clutter the code.  Unfortunately, I can't figure out how to make
>> Coccinelle drop all of them, so I have to settle for common special
>> cases:
>>
>>      @@
>>      type T;
>>      T *pt;
>>      void *pv;
>>      @@
>>      - pt = (T *)pv;
>>      + pt = pv;
>>      @@
>>      type T;
>>      @@
>>      - (T *)
>>        (\(g_malloc\|g_malloc0\|g_realloc\|g_new\|g_new0\|g_renew\|
>> 	 g_try_malloc\|g_try_malloc0\|g_try_realloc\|
>> 	 g_try_new\|g_try_new0\|g_try_renew\)(...))
>>
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> ---
>>   block/sheepdog.c    | 2 +-
>>   block/vhdx-log.c    | 2 +-
>>   block/vvfat.c       | 8 ++++----
>>   hw/ide/microdrive.c | 2 +-
>>   4 files changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/block/sheepdog.c b/block/sheepdog.c
>> index 0709fd0..340bdf6 100644
>> --- a/block/sheepdog.c
>> +++ b/block/sheepdog.c
>> @@ -2202,7 +2202,7 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
>>           goto cleanup;
>>       }
>>   -    inode = (SheepdogInode *)g_malloc(datalen);
>> +    inode = g_malloc(datalen);
>>         ret = read_object(fd, (char *)inode,
>> vid_to_vdi_oid(new_vid),
>>                         s->inode.nr_copies, datalen, 0, s->cache_flags);
>> diff --git a/block/vhdx-log.c b/block/vhdx-log.c
>> index 3eb7e68..f07328d 100644
>> --- a/block/vhdx-log.c
>> +++ b/block/vhdx-log.c
>> @@ -909,7 +909,7 @@ static int vhdx_log_write(BlockDriverState *bs, BDRVVHDXState *s,
>>       buffer = qemu_blockalign(bs, total_length);
>>       memcpy(buffer, &new_hdr, sizeof(new_hdr));
>>   -    new_desc = (VHDXLogDescriptor *) (buffer + sizeof(new_hdr));
>> +    new_desc = buffer + sizeof(new_hdr);
>
> Perhaps we should try to fix void pointer arithmetic some time...

Fixes for that tend to involve back-and-forth type casting.  I find that
cure not much of an improvement over the disease :)

> Anyway:
>
> Reviewed-by: Max Reitz <mreitz@redhat.com>

Thanks!