Re: PCI: Add TLP Prefix reading to pcie_read_tlp_log()

[Colin King (gmail)]

On 16/01/2025 16:18, Ilpo Järvinen wrote:
> On Thu, 16 Jan 2025, Colin King (gmail) wrote:
>
> > Hi,
> >
> > Static analysis shows there is a potential issue in the following commit:
> >
> > commit 00048c2d5f113bb4e82a0a30dfc4ee12590b81f5
> > Author: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> > Date:   Tue Jan 14 19:08:39 2025 +0200
> >
> >      PCI: Add TLP Prefix reading to pcie_read_tlp_log()
> >
> >
> > The issue is described as follows:
> >
> > unsigned int aer_tlp_log_len(struct pci_dev *dev, u32 aercc)
> > {
> >          return PCIE_STD_NUM_TLP_HEADERLOG +
> >                 (aercc & PCI_ERR_CAP_PREFIX_LOG_PRESENT) ?
> >                 dev->eetlp_prefix_max : 0;
> > }
> >
> >
> > static analysis is warning that the left hand size of the ? operator is always
> > true and so dev->eetlp_prefix_max is always being returned and the 0 is never
> > returned (dead code).
> >
> > I suspect the expected behaviour is as follows:
> >
> >          return PCIE_STD_NUM_TLP_HEADERLOG +
> >                 ((aercc & PCI_ERR_CAP_PREFIX_LOG_PRESENT) ?
> >                 dev->eetlp_prefix_max : 0);
> >
> > ..I'm reluctant to send a fix in case this is not the original intention.
>
> Your fix looks correct, it should have the parenthesis due to operator
> precedence rules. The intention is to calculate 4 DWs + optionally n E-E
> TLP prefixes.

OK, I'll send a patch later today.

Colin

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