[sheepdog] [PATCH v3 08/17] block/io: support int64_t bytes in bdrv_aligned_preadv()

[Alberto Garcia]

On Fri 22 May 2020 05:14:36 PM CEST, Eric Blake wrote:
>>   static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
>> -    BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
>> +    BdrvTrackedRequest *req, int64_t offset, int64_t bytes,
>>       int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
 [...]
>>       BlockDriverState *bs = child->bs;
>>       int64_t total_bytes, max_bytes;
>>       int ret = 0;
>> -    uint64_t bytes_remaining = bytes;
>> +    int64_t bytes_remaining = bytes;
>>       int max_transfer;
>>   
>>       assert(is_power_of_2(align));
>> +    assert(offset >= 0 && bytes >= 0);
>
> Use within the function:
>
> the new assertion added here does not check for whether offset+bytes is 
> positive; I would suggest we strengthen it to instead be:
> assert(offset >= 0 && (uint64_t) bytes <= INT64_MAX - offset);

But here you would be making 'bytes' unsigned without asserting that
it's not negative.

Berto