On Wed, Sep 04, 2024 at 08:12:19PM +0300, Dan Carpenter wrote: > On Wed, Sep 04, 2024 at 08:17:11AM -0700, Nicolin Chen wrote: > > Hi Dan, > > > > On Wed, Sep 04, 2024 at 10:29:26AM +0300, Dan Carpenter wrote: > > > > > I was reviewing Smatch warnings: > > > > > > drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c:616 tegra241_cmdqv_init_vintf() > > > error: Calling ida_alloc_max() with a 'max' argument which is a power of 2. -1 missing? > > > > > > The problem is that we're calling ida_alloc_max() where max is always zero. > > > > > > > +static int tegra241_cmdqv_init_vintf(struct tegra241_cmdqv *cmdqv, u16 max_idx, > > > > + struct tegra241_vintf *vintf) > > > > +{ > > > > + > > > > + u16 idx; > > > > + int ret; > > > > + > > > > + ret = ida_alloc_max(&cmdqv->vintf_ids, max_idx, GFP_KERNEL); > > > > + if (ret < 0) > > > > + return ret; > > > > + idx = ret; > > > > > > max_idx is always zero so idx is always zero. > > > > There is a followup series adding support for max[1, max_vintf]. > > And I guess that would make Smatch happy. I'd personally prefer > > keep this by ignoring the Smatch warning. But if you think the > > common practice is to drop it and add back, I'd be okay with it. > > > > I'm just reviewing static checker warnings so I don't know the back story... > How long are we going to have to wait for the follow on patchset? There are a couple of dependencies we need to get merged first. So, it might take a few months I think. Perhaps I can make a small patch by changing the ida_alloc_max in the common place here to iad_alloc_range(.., 1, max,..) in the caller of the followup series. Then the existing caller for vintf0 wouldn't need an ida_alloc(). > Generally if someone had noticed this in review they would have asked that it > be dropped but now that it's in, you're probably in the clear. No one else is > going to volunteer to refactor this code if you don't. ;) > > With regards, to ignoring static checker warnings. These are one time emails. > There is always going to be a certain percent of false positives. You're > *encouraged* to ignore static checker warnings unless it's a bug or it makes the > code cleaner. The goal is never to silence the checker. I see. Thanks for the note! Nicolin