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SubjectRe: [PATCH 11/19] regmap: avoid undefined return from regmap_read_debugfs
On Sat, Jan 26, 2013 at 05:49:29PM +0800, Mark Brown wrote:
> Oh, ffs. This is a false positive from the compiler - there is no case
> where it can actually do this as we will bail out before the walk if the
> list is empty so we'll always take at least one trip through our
> list_for_each_entry() and either return or set ret. It should be smart
> enough to work out that the list_empty() means list_for_each_entry()
> will iterate over at least one entry or more conservative in what it
> warns about.

Why not code the function in a way that avoids the problem altogether?

/*
* This should never happen; we return above if we fail to
* allocate and we should never be in this code if there are
* no registers at all.
*/
- if (list_empty(&map->debugfs_off_cache)) {
- WARN_ON(list_empty(&map->debugfs_off_cache));
- return base;
- }
+ WARN_ON(list_empty(&map->debugfs_off_cache));
+ ret = base;

/* Find the relevant block */
list_for_each_entry(c, &map->debugfs_off_cache, list) {
if (from >= c->min && from <= c->max) {
*pos = c->min;
return c->base_reg;
}

*pos = c->min;
ret = c->base_reg;
}

return ret;


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