Re: [PATCH v3 1/7] seqnum_ops: Introduce Sequence Number Ops

[Greg KH]

On Wed, Feb 03, 2021 at 11:11:57AM -0700, Shuah Khan wrote:
> +static inline u32 seqnum32_inc(struct seqnum32 *seq)
> +{
> +	atomic_t val = ATOMIC_INIT(seq->seqnum);
> +
> +	seq->seqnum = (u32) atomic_inc_return(&val);
> +	if (seq->seqnum >= UINT_MAX)
> +		pr_info("Sequence Number overflow %u detected\n",
> +			seq->seqnum);
> +	return seq->seqnum;

As Peter points out, this is doing doing what you think it is doing :(

Why do you not just have seq->seqnum be a real atomic variable?  Trying
to switch to/from one like this does not work as there is no
"atomic-ness" happening here at all.

Oh, and checkpatch should have complained about the extra ' ' in your
cast :)

thanks,

greg k-h