Re: [PATCH] PCI: Mediatek: Use resource_size function on resource object

Honghui Zhang
2019-01-31T01:21:38Z

On Wed, 2019-01-30 at 16:31 +0000, Lorenzo Pieralisi wrote:
> On Wed, Jan 30, 2019 at 09:58:53AM -0600, Bjorn Helgaas wrote:
> > On Wed, Jan 30, 2019 at 12:33:47PM +0000, Lorenzo Pieralisi wrote:
> > > On Wed, Jan 02, 2019 at 02:03:53PM +0800, honghui.zhang@mediatek.com wrote:
> > > > From: Honghui Zhang <honghui.zhang@mediatek.com>
> > > >
> > > > drivers/pci/pcie-mediatek.c:720:13-16: WARNING: Suspicious code. resource_size is maybe missing with mem
> > > >
> > > > Generated by: scripts/coccinelle/api/resource_size.cocci
> > > >
> > > > Signed-off-by: Honghui Zhang <honghui.zhang@mediatek.com>
> > > > ---
> > > > drivers/pci/controller/pcie-mediatek.c | 4 +---
> > > > 1 file changed, 1 insertion(+), 3 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> > > > index e307166..0168376 100644
> > > > --- a/drivers/pci/controller/pcie-mediatek.c
> > > > +++ b/drivers/pci/controller/pcie-mediatek.c
> > > > @@ -654,7 +654,6 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
> > > > struct resource *mem = &pcie->mem;
> > > > const struct mtk_pcie_soc *soc = port->pcie->soc;
> > > > u32 val;
> > > > - size_t size;
> > > > int err;
> > > >
> > > > /* MT7622 platforms need to enable LTSSM and ASPM from PCIe subsys */
> > > > @@ -706,8 +705,7 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
> > > > mtk_pcie_enable_msi(port);
> > > >
> > > > /* Set AHB to PCIe translation windows */
> > > > - size = mem->end - mem->start;
> > > > - val = lower_32_bits(mem->start) | AHB2PCIE_SIZE(fls(size));
> > > > + val = lower_32_bits(mem->start) | AHB2PCIE_SIZE(fls(resource_size(mem)));
> > >
> > > checkpatch warns on this line, please make sure patches pass it before
> > > posting them.
> >
> > I didn't actually run checkpatch myself, so I don't know why it
> > complained.
>
> WARNING: line over 80 characters
> #35: FILE: drivers/pci/controller/pcie-mediatek.c:708:
> + val = lower_32_bits(mem->start) | AHB2PCIE_SIZE(fls(resource_size(mem)));
>
> I do run it as a sanity check.
>
> > The patch you merged moves "mem_size = resource_size(mem)" higher up,
> > away from the previous location and its use, which makes it a little
> > harder to read.
>
> That's because it was how the original code (which as you pointed out
> is likely buggy) was written.
>
> Anyway patch dropped waiting for a v2 consistent with your review -
> apologies for missing some key review points.
>

Thanks for your comments, I will send a v2 and fix all the issue you
pointed out.

> Lorenzo