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

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On 2/5/21 2:58 AM, Greg KH wrote:
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.


Yes. This is sloppy on my part. As Peter and Rafael also pointed. I have
to start paying more attention to my inner voice.

thanks,
-- Shuah






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