[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v8 0/7] Add pci_dev_for_each_resource() helper and update users
On Thu, Jun 01, 2023 at 07:25:46PM +0300, Andy Shevchenko wrote: > On Wed, May 31, 2023 at 08:48:35PM +0200, Jonas Gorski wrote: > > On Tue, 30 May 2023 at 23:34, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > On Fri, May 12, 2023 at 02:48:51PM -0500, Bjorn Helgaas wrote: ... > > > Where are we at? Are we going to ignore this because some Coverity > > > reports are false positives? > > > > Looking at the code I understand where coverity is coming from: > > > > #define __pci_dev_for_each_res0(dev, res, ...) \ > > for (unsigned int __b = 0; \ > > res = pci_resource_n(dev, __b), __b < PCI_NUM_RESOURCES; \ > > __b++) > > > > res will be assigned before __b is checked for being less than > > PCI_NUM_RESOURCES, making it point to behind the array at the end of > > the last loop iteration. > > Which is fine and you stumbled over the same mistake I made, that's why the > documentation has been added to describe why the heck this macro is written > the way it's written. > > Coverity sucks. > > > Rewriting the test expression as > > > > __b < PCI_NUM_RESOURCES && (res = pci_resource_n(dev, __b)); > > > > should avoid the (coverity) warning by making use of lazy evaluation. > > Obviously NAK. > > > It probably makes the code slightly less performant as res will now be > > checked for being not NULL (which will always be true), but I doubt it > > will be significant (or in any hot paths). Oh my god, I mistakenly read this as bus macro, sorry for my rant, it's simply wrong. -- With Best Regards, Andy Shevchenko
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