Re: [PATCH v4 6/6] block: use chunk_sectors when evaluating stacked atomic write limits

[John Garry <john.g.garry@oracle.com>]

On 08/07/2025 17:59, Mikulas Patocka wrote:
>>> +
>>> +	/*
>>> +	 * If chunk sectors is so large that its value in bytes overflows
>>> +	 * UINT_MAX, then just shift it down so it definitely will fit.
>>> +	 * We don't support atomic writes of such a large size anyway.
>>> +	 */
>>> +	if ((unsigned long)chunk_sectors << SECTOR_SHIFT > UINT_MAX)
>>> +		chunk_bytes = chunk_sectors;
>>> +	else
>>> +		chunk_bytes = chunk_sectors << SECTOR_SHIFT;
> Why do we cast it to unsigned long? unsigned long is 32-bit on 32-bit
> machines, so the code will not detect the overflow in that case. We should
> cast it to unsigned long long (or uint64_t).

Right, I said earlier that I would use an unsigned long long, but didn't 
do it that way, which was unintentional.

Anyway, I will change this code as suggested by Nilay.

Thanks,
John