On 2012/10/12 13:35, Jon Mason wrote:
> Coverity noticed that pcie_bus_configure_settings() can call
> pcie_bus_configure_set() when "smpss" is uninitialized. The smpss is
> used to make the bus and all child devices have a uniform value.
> Setting the smpss is moot for PCIE_BUS_PERFORMANCE, since it will be
> determined dynamically based on the max size of the parent device and
> the child device. To avoid the erroneous detection of this issue, set
> the smpss to 0. Also, add a case statement to make clearer the possible
> use cases and add a nice comment describing what is being done in the
> PCIE_BUS_PERFORMANCE case.
>
> Signed-off-by: Jon Mason <jdmason@xxxxxxxx>
> ---
> drivers/pci/probe.c | 25 ++++++++++++++++++++-----
> 1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 9f8a6b7..6b672c1 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1570,21 +1570,36 @@ void pcie_bus_configure_settings(struct pci_bus *bus, u8 mpss)
> if (!pci_is_pcie(bus->self))
> return;
>
> - if (pcie_bus_config == PCIE_BUS_TUNE_OFF)
> - return;
> -
> + switch (pcie_bus_config) {
> + /* The smpss is used to make the bus and all child devices have
> + * a uniform value. Setting the smpss is moot for
> + * "Performance", since it will be determined dynamically based
> + * on the max size of the parent device and the child device.
> + * However, not setting the smpss can result in static code
> + * analysis tools erroniously reporting an issue. To avoid
> + * this, set the smpss to 0.
> + */
> + case PCIE_BUS_PERFORMANCE:
> /* FIXME - Peer to peer DMA is possible, though the endpoint would need
> * to be aware to the MPS of the destination. To work around this,
> * simply force the MPS of the entire system to the smallest possible.
> */
> - if (pcie_bus_config == PCIE_BUS_PEER2PEER)
> + case PCIE_BUS_PEER2PEER:
> smpss = 0;
> + break;
>
> - if (pcie_bus_config == PCIE_BUS_SAFE) {
> + case PCIE_BUS_SAFE:
> smpss = mpss;
>
> pcie_find_smpss(bus->self, &smpss);
> pci_walk_bus(bus, pcie_find_smpss, &smpss);
> + break;
> +
> + case PCIE_BUS_TUNE_OFF:
> + default:
> + return;
> + }
> +
> }
Remove bracket }
>
> pcie_bus_configure_set(bus->self, &smpss);
>
--
Thanks!
Yijing
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