Re: [Qemu-devel] [PATCH 1/1] nbd: fix max_discard/max_transfer_length

[Peter Lieven <pl@kamp.de>]

Am 06.02.2015 um 12:53 schrieb Kevin Wolf:
> Am 06.02.2015 um 12:24 hat Denis V. Lunev geschrieben:
>> nbd_co_discard calls nbd_client_session_co_discard which uses uint32_t
>> as the length in bytes of the data to discard due to the following
>> definition:
>>
>> struct nbd_request {
>>     uint32_t magic;
>>     uint32_t type;
>>     uint64_t handle;
>>     uint64_t from;
>>     uint32_t len; <-- the length of data to be discarded, in bytes
>> } QEMU_PACKED;
>>
>> Thus we should limit bl_max_discard to UINT32_MAX >> BDRV_SECTOR_BITS to
>> avoid overflow.
>>
>> NBD read/write code uses the same structure for transfers. Fix
>> max_transfer_length accordingly.
>>
>> Signed-off-by: Denis V. Lunev <den@openvz.org>
>> CC: Peter Lieven <pl@kamp.de>
>> CC: Kevin Wolf <kwolf@redhat.com>
> Thanks, I have applied both Peter's and your patch. Can you guys please
> check whether the current state of my block branch is correct or whether
> I forgot to include or remove some patch?

Looks good from my point of view.

Just to be sure has it to be

if (size > BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)

or

if (size > (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS))

?

If the latter is right, can you please fix that line in my patch. I am afk now.

Thanks,
Peter