ACK: [SRU][N][PATCH 0/1] Compile error due to nonexistent struct member with CONFIG_PCI_EPF_TEST

[Yufeng Gao]

On 2/4/26 12:55, Noah Wager wrote:
> BugLink: https://bugs.launchpad.net/bugs/2147065
>
> [ Impact ]
>
> The noble 6.8 kernel fails to build when CONFIG_PCI_EPF_TEST is enabled, with
> the following error:
>
> ```
>      CC [M] drivers/pci/endpoint/functions/pci-epf-test.o
>    drivers/pci/endpoint/functions/pci-epf-test.c: In function 'pci_epf_test_alloc_space':
>    drivers/pci/endpoint/functions/pci-epf-test.c:863:33: error: 'const struct pci_epc_features' has no member named 'bar'
>      863 | if (epc_features->bar[bar].type == BAR_FIXED)
>          | ^~
>    drivers/pci/endpoint/functions/pci-epf-test.c:863:52: error: 'BAR_FIXED' undeclared (first use in this function)
>      863 | if (epc_features->bar[bar].type == BAR_FIXED)
>          | ^~~~~~~~~
>    drivers/pci/endpoint/functions/pci-epf-test.c:863:52: note: each undeclared identifier is reported only once for each function it appears in
>    drivers/pci/endpoint/functions/pci-epf-test.c:864:53: error: 'const struct pci_epc_features' has no member named 'bar'
>      864 | test_reg_size = epc_features->bar[bar].fixed_size;
>          | ^~
>    make[8]: *** [scripts/Makefile.build:243: drivers/pci/endpoint/functions/pci-epf-test.o] Error 1
>    make[7]: *** [scripts/Makefile.build:481: drivers/pci/endpoint/functions] Error 2
>    make[6]: *** [scripts/Makefile.build:481: drivers/pci/endpoint] Error 2
> ```
>
> This is due to the inclusion of the linux-6.12.y upstream stable commit:
> e741dabcc52b ("PCI: endpoint: pci-epf-test: Limit PCIe BAR size for fixed BARs")
> without including the dependent (non-stable) commit:
> e01c9797c0eb ("PCI: endpoint: Clean up hardware description for BARs")
>
> The 6.12 commit does not fix any issues that have been observed with the 6.8
> noble kernel, so it should be reverted. After doing so, the kernel compiles
> when the config is enabled.
>
> [ Test Plan ]
>
> 1. Apply the revert.
> 2. Enable CONFIG_PCI_EPF_TEST in the generic 6.8 kernel
> 3. Compile the kernel.
>
> The compilation should succeed with the revert.
>
> [ Where problems could occur ]
>
> Since this config is disabled in Ubuntu by default, it has not been tested in
> the past. Even though it compiles with this fix, that does not guarantee
> correct behaviour in the features that the config enables. For example,
> reverting this commit means the feature will definitely not work with
> controllers with too-small fixed BAR sizes, as that is what the commit fixes
> upstream. If it is needed, a full backport of the commit and its dependents will
> be necessary.
>
> [ Other Info ]
>
> For context, this issue was found because the noble:linux-nvidia-tegra kernel
> needs to enable PCI_EPF_TEST, so more issues may be found once that gets further
> testing.
>
> Noah Wager (1):
>    UBUNTU: SAUCE: Revert "PCI: endpoint: pci-epf-test: Limit PCIe BAR
>      size for fixed BARs"
>
>   drivers/pci/endpoint/functions/pci-epf-test.c | 7 +------
>   1 file changed, 1 insertion(+), 6 deletions(-)
>
Acked-by: Yufeng Gao <yufeng.gao at canonical.com>