Re: [PATCH net] net: ethernet: adi: adin1110: Fix some error handling path in adin1110_read_fifo()

[Dan Carpenter]

On Thu, Oct 03, 2024 at 08:53:15PM +0200, Christophe JAILLET wrote:
> If 'frame_size' is too small or if 'round_len' is an error code, it is
> likely that an error code should be returned to the caller.
> 
> Actually, 'ret' is likely to be 0, so if one of these sanity checks fails,
> 'success' is returned.
> 
> Return -EINVAL instead.
> 
> Fixes: bc93e19d088b ("net: ethernet: adi: Add ADIN1110 support")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> ---
> This patch is speculative.
> If returning 0 is what was intended, then an explicit 0 would be better.

I have an unpublished Smatch warning for these:

drivers/net/ethernet/adi/adin1110.c:321 adin1110_read_fifo() info: returning a literal zero is cleaner
drivers/net/ethernet/adi/adin1110.c:325 adin1110_read_fifo() info: returning a literal zero is cleaner

It's a pity that deliberately doing a "return ret;" when ret is zero is so
common.  Someone explained to me that it was "done deliberately to express that
we were propagating the success from frob_whatever()".  No no no!

I don't review these warnings unless I'm fixing a bug in the driver because
they're too common.  The only ones I review are:

	ret = frob();
	if (!ret)
		return ret;

Maybe 20% of the time those warnings indicate a reversed if statement.

Your heuristic here is very clever and I'll try steal it to create a new more
specific warning.

regards,
dan carpenter