From: Bjorn Helgaas <helgaas@kernel.org>
To: Jonas Gorski <jonas.gorski@gmail.com>
Cc: "Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Krzysztof Wilczyński" <kw@linux.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
"Mickaël Salaün" <mic@digikod.net>,
"Rich Felker" <dalias@libc.org>,
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"Andrew Lunn" <andrew@lunn.ch>,
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"Yoshinori Sato" <ysato@users.sourceforge.jp>,
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"Oleksandr Tyshchenko" <oleksandr_tyshchenko@epam.com>,
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"David S. Miller" <davem@davemloft.net>,
"Maciej W. Rozycki" <macro@orcam.me.uk>
Subject: Re: [PATCH v8 0/7] Add pci_dev_for_each_resource() helper and update users
Date: Wed, 31 May 2023 16:30:28 -0500 [thread overview]
Message-ID: <ZHe8dKb3f392MfBO@bhelgaas> (raw)
In-Reply-To: <CAOiHx==5YWhDiZP2PyHZiJrmtqRzvqCqoSO59RwuYuR85BezBg@mail.gmail.com>
On Wed, May 31, 2023 at 08:48:35PM +0200, Jonas Gorski wrote:
> ...
> 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.
>
> 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.
>
> 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).
Thanks a lot for looking into this! I think you're right, and I think
the rewritten expression is more logical as well. Do you want to post
a patch for it?
Bjorn
next prev parent reply other threads:[~2023-05-31 21:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-30 16:24 [PATCH v8 0/7] Add pci_dev_for_each_resource() helper and update users Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 1/7] kernel.h: Split out COUNT_ARGS() and CONCATENATE() Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 2/7] PCI: Introduce pci_resource_n() Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 3/7] PCI: Introduce pci_dev_for_each_resource() Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 4/7] PCI: Document pci_bus_for_each_resource() to avoid confusion Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 5/7] PCI: Allow pci_bus_for_each_resource() to take less arguments Andy Shevchenko
2023-04-05 11:50 ` Andy Shevchenko
2023-04-05 20:11 ` Bjorn Helgaas
2023-03-30 16:24 ` [PATCH v8 6/7] EISA: Convert to use less arguments in pci_bus_for_each_resource() Andy Shevchenko
2023-03-30 16:24 ` [PATCH v8 7/7] pcmcia: " Andy Shevchenko
2023-04-05 8:30 ` Andy Shevchenko
2023-04-04 16:11 ` [PATCH v8 0/7] Add pci_dev_for_each_resource() helper and update users Bjorn Helgaas
2023-04-05 8:28 ` Andy Shevchenko
2023-04-05 20:18 ` Bjorn Helgaas
2023-04-06 10:31 ` Andy Shevchenko
2023-05-09 18:21 ` Bjorn Helgaas
2023-05-12 10:56 ` Andy Shevchenko
2023-05-12 19:48 ` Bjorn Helgaas
2023-05-30 21:24 ` Bjorn Helgaas
[not found] ` <CAOiHx==5YWhDiZP2PyHZiJrmtqRzvqCqoSO59RwuYuR85BezBg@mail.gmail.com>
2023-05-31 21:30 ` Bjorn Helgaas [this message]
2023-06-01 11:17 ` Jonas Gorski
2023-06-05 14:04 ` Andy Shevchenko
2023-06-01 16:25 ` Andy Shevchenko
2023-06-01 16:27 ` Andy Shevchenko
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