Subject: Re: [PATCH 3/5] dma-mapping: make support for dma ops optional

From: Guenter Roeck <[email-masked]>
Date: Sat, 18 Jul 2020 10:17:14 -0700

On Wed, Jul 08, 2020 at 05:24:47PM +0200, Christoph Hellwig wrote:
> Avoid the overhead of the dma ops support for tiny builds that only
> use the direct mapping.
> 
> Signed-off-by: Christoph Hellwig <[email-masked]>

For ppc:pmac32_defconfig and other configurations, this patch results in:

Error log:
drivers/macintosh/macio_asic.c: In function 'macio_add_one_device':
drivers/macintosh/macio_asic.c:393:16: error: 'struct device' has no member named 'dma_ops'
  393 |  dev->ofdev.dev.dma_ops = chip->lbus.pdev->dev.dma_ops;
      |                ^
drivers/macintosh/macio_asic.c:393:47: error: 'struct device' has no member named 'dma_ops'
  393 |  dev->ofdev.dev.dma_ops = chip->lbus.pdev->dev.dma_ops;
      |                                               ^

Bisect log attached.

Guenter

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# bad: [aab7ee9f8ff0110bfcd594b33dc33748dc1baf46] Add linux-next specific files for 20200717
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git bisect bad 4406fe306759d700f2b2aa8adf890a7d7ef064ae
# bad: [27f18f0e00ed1f15ee55d479216c874561b6b70a] Merge remote-tracking branch 'arm-soc/for-next'
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git bisect good 05d94a2de41e8d9840d9749d553febdcf99cb0e5
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# bad: [88ff79e455afa3ac90739da27e24f655a965e3cf] Merge remote-tracking branch 'dma-mapping/for-next'
git bisect bad 88ff79e455afa3ac90739da27e24f655a965e3cf
# good: [7c4d50d4973b40c53ef6c592b41b0473127e6762] kbuild: do not export LDFLAGS_vmlinux
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# good: [c45db534668104ed5112ed371526db6096ac5742] Merge remote-tracking branch 'kbuild/for-next'
git bisect good c45db534668104ed5112ed371526db6096ac5742
# bad: [249542813648f7a278895ad25674d3e147f49ad6] dma-mapping: make support for dma ops optional
git bisect bad 249542813648f7a278895ad25674d3e147f49ad6
# good: [b4174173005972f8f6497883d08d87e0aba1b604] dma-mapping: inline the fast path dma-direct calls
git bisect good b4174173005972f8f6497883d08d87e0aba1b604
# first bad commit: [249542813648f7a278895ad25674d3e147f49ad6] dma-mapping: make support for dma ops optional