From: Michael Ellerman <mpe@ellerman•id.au>
To: Nathan Chancellor <natechancellor@gmail•com>,
Oliver O'Halloran <oohall@gmail•com>
Cc: clang-built-linux@googlegroups•com, linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH v2 15/16] powerpc/powernv/sriov: Make single PE mode a per-BAR setting
Date: Sun, 02 Aug 2020 23:12:23 +1000 [thread overview]
Message-ID: <87r1sp19ag.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20200801061823.GA1203340@ubuntu-n2-xlarge-x86>
Nathan Chancellor <natechancellor@gmail•com> writes:
> On Wed, Jul 22, 2020 at 04:57:14PM +1000, Oliver O'Halloran wrote:
>> Using single PE BARs to map an SR-IOV BAR is really a choice about what
>> strategy to use when mapping a BAR. It doesn't make much sense for this to
>> be a global setting since a device might have one large BAR which needs to
>> be mapped with single PE windows and another smaller BAR that can be mapped
>> with a regular segmented window. Make the segmented vs single decision a
>> per-BAR setting and clean up the logic that decides which mode to use.
>>
>> Signed-off-by: Oliver O'Halloran <oohall@gmail•com>
>> ---
>> v2: Dropped unused total_vfs variables in pnv_pci_ioda_fixup_iov_resources()
>> Dropped bar_no from pnv_pci_iov_resource_alignment()
>> Minor re-wording of comments.
>> ---
>> arch/powerpc/platforms/powernv/pci-sriov.c | 131 ++++++++++-----------
>> arch/powerpc/platforms/powernv/pci.h | 11 +-
>> 2 files changed, 73 insertions(+), 69 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/powernv/pci-sriov.c b/arch/powerpc/platforms/powernv/pci-sriov.c
>> index ce8ad6851d73..76215d01405b 100644
>> --- a/arch/powerpc/platforms/powernv/pci-sriov.c
>> +++ b/arch/powerpc/platforms/powernv/pci-sriov.c
>> @@ -260,42 +256,40 @@ void pnv_pci_ioda_fixup_iov(struct pci_dev *pdev)
>> resource_size_t pnv_pci_iov_resource_alignment(struct pci_dev *pdev,
>> int resno)
>> {
>> - struct pnv_phb *phb = pci_bus_to_pnvhb(pdev->bus);
>> struct pnv_iov_data *iov = pnv_iov_get(pdev);
>> resource_size_t align;
>>
>> + /*
>> + * iov can be null if we have an SR-IOV device with IOV BAR that can't
>> + * be placed in the m64 space (i.e. The BAR is 32bit or non-prefetch).
>> + * In that case we don't allow VFs to be enabled since one of their
>> + * BARs would not be placed in the correct PE.
>> + */
>> + if (!iov)
>> + return align;
>> + if (!iov->vfs_expanded)
>> + return align;
>> +
>> + align = pci_iov_resource_size(pdev, resno);
That's, oof.
> I am not sure if it has been reported yet but clang points out that
> align is initialized after its use:
>
> arch/powerpc/platforms/powernv/pci-sriov.c:267:10: warning: variable 'align' is uninitialized when used here [-Wuninitialized]
> return align;
> ^~~~~
> arch/powerpc/platforms/powernv/pci-sriov.c:258:23: note: initialize the variable 'align' to silence this warning
> resource_size_t align;
> ^
> = 0
> 1 warning generated.
But I can't get gcc to warn about it?
It produces some code, so it's not like the whole function has been
elided or something. I'm confused.
cheers
next prev parent reply other threads:[~2020-08-02 13:14 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 6:57 [PATCH v2 01/16] powernv/pci: Add pci_bus_to_pnvhb() helper Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 02/16] powerpc/powernv/pci: Always tear down DMA windows on PE release Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 03/16] powerpc/powernv/pci: Add explicit tracking of the DMA setup state Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 04/16] powerpc/powernv/pci: Initialise M64 for IODA1 as a 1-1 window Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 05/16] powerpc/powernv/sriov: Move SR-IOV into a separate file Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 06/16] powerpc/powernv/sriov: Explain how SR-IOV works on PowerNV Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 07/16] powerpc/powernv/sriov: Rename truncate_iov Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 08/16] powerpc/powernv/sriov: Simplify used window tracking Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 09/16] powerpc/powernv/sriov: Factor out M64 BAR setup Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 10/16] powerpc/powernv/pci: Refactor pnv_ioda_alloc_pe() Oliver O'Halloran
2020-07-24 5:20 ` Alexey Kardashevskiy
2020-07-22 6:57 ` [PATCH v2 11/16] powerpc/powernv/sriov: Drop iov->pe_num_map[] Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 12/16] powerpc/powernv/sriov: De-indent setup and teardown Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 13/16] powerpc/powernv/sriov: Move M64 BAR allocation into a helper Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 14/16] powerpc/powernv/sriov: Refactor M64 BAR setup Oliver O'Halloran
2020-07-22 6:57 ` [PATCH v2 15/16] powerpc/powernv/sriov: Make single PE mode a per-BAR setting Oliver O'Halloran
2020-08-01 6:18 ` Nathan Chancellor
2020-08-02 13:12 ` Michael Ellerman [this message]
2020-08-03 4:46 ` Nathan Chancellor
2020-08-03 5:57 ` Michael Ellerman
2020-08-03 21:00 ` Segher Boessenkool
2020-07-22 6:57 ` [PATCH v2 16/16] powerpc/powernv/sriov: Remove vfs_expanded Oliver O'Halloran
2020-07-27 7:26 ` [PATCH v2 01/16] powernv/pci: Add pci_bus_to_pnvhb() helper Michael Ellerman
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