[PATCH v2 00/21] Allow compile-testing NO_DMA (drivers)

Geert Uytterhoeven
2018-03-16T14:55:12Z

Hi all,

If NO_DMA=y, get_dma_ops() returns a reference to the non-existing
symbol bad_dma_ops, thus causing a link failure if it is ever used.

The intention of this is twofold:
1. To catch users of the DMA API on systems that do no support the DMA
mapping API,
2. To avoid building drivers that cannot work on such systems anyway.

However, the disadvantage is that we have to keep on adding dependencies
on HAS_DMA all over the place.

Thanks to the COMPILE_TEST symbol, lots of drivers now depend on one or
more platform dependencies (that imply HAS_DMA) || COMPILE_TEST, thus
already covering intention #2. Having to add an explicit dependency on
HAS_DMA here is cumbersome, and hinders compile-testing.

Hence I think the time is ripe to reconsider the link failure.
Patch series "[PATCH v2 0/5] Allow compile-testing NO_DMA (core)"
(https://lkml.org/lkml/2018/3/16/435) already:
- Changed get_dma_ops() to return NULL instead,
- Added a few more dummies to enable compile-testing.

This patch series:
- Removes dependencies on HAS_DMA for symbols that already have
platform dependencies implying HAS_DMA.

To avoid allmodconfig/allyesconfig regressions on NO_DMA=y platforms,
this (drivers) series should be applied after the previous (core)
series (but not many people may notice/care ;-)

Changes compared to v1:
- Add Reviewed-by, Acked-by,
- Drop dependency of SND_SOC_LPASS_IPQ806X on HAS_DMA,
- Drop dependency of VIDEOBUF{,2}_DMA_{CONTIG,SG} on HAS_DMA,
- Drop new dependencies of VIDEO_IPU3_CIO2, DVB_C8SECTPFE, and
MTD_NAND_MARVELL on HAS_DMA,
- Split in per-subsystem patches,
- Split-off the core part in a separate series.

This series is against v4.16-rc5. It can also be found at
https://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k.git/log/?h=no-dma-compile-testing-v2

It has been compile-tested with allmodconfig and allyesconfig for
m68k/sun3, and has received attention from the kbuild test robot.

Thanks!

Geert Uytterhoeven (21):
ASoC: Remove depends on HAS_DMA in case of platform dependency
ata: Remove depends on HAS_DMA in case of platform dependency
crypto: Remove depends on HAS_DMA in case of platform dependency
fbdev: Remove depends on HAS_DMA in case of platform dependency
firewire: Remove depends on HAS_DMA in case of platform dependency
fpga: Remove depends on HAS_DMA in case of platform dependency
i2c: Remove depends on HAS_DMA in case of platform dependency
iio: adc: Remove depends on HAS_DMA in case of platform dependency
iommu: Remove depends on HAS_DMA in case of platform dependency
lightnvm: Remove depends on HAS_DMA in case of platform dependency
mailbox: Remove depends on HAS_DMA in case of platform dependency
media: Remove depends on HAS_DMA in case of platform dependency
mmc: Remove depends on HAS_DMA in case of platform dependency
mtd: Remove depends on HAS_DMA in case of platform dependency
net: Remove depends on HAS_DMA in case of platform dependency
remoteproc: Remove depends on HAS_DMA in case of platform dependency
scsi: hisi_sas: Remove depends on HAS_DMA in case of platform
dependency
serial: Remove depends on HAS_DMA in case of platform dependency
spi: Remove depends on HAS_DMA in case of platform dependency
staging: vc04_services: Remove depends on HAS_DMA in case of platform
dependency
usb: Remove depends on HAS_DMA in case of platform dependency

drivers/ata/Kconfig | 2 --
drivers/crypto/Kconfig | 14 +++------
drivers/firewire/Kconfig | 1 -
drivers/fpga/Kconfig | 1 -
drivers/i2c/busses/Kconfig | 3 --
drivers/iio/adc/Kconfig | 2 --
drivers/iommu/Kconfig | 5 ++--
drivers/lightnvm/Kconfig | 2 +-
drivers/mailbox/Kconfig | 2 --
drivers/media/common/videobuf2/Kconfig | 2 --
drivers/media/pci/dt3155/Kconfig | 1 -
drivers/media/pci/intel/ipu3/Kconfig | 1 -
drivers/media/pci/solo6x10/Kconfig | 1 -
drivers/media/pci/sta2x11/Kconfig | 1 -
drivers/media/pci/tw5864/Kconfig | 1 -
drivers/media/pci/tw686x/Kconfig | 1 -
drivers/media/platform/Kconfig | 40 ++++++++-----------------
drivers/media/platform/am437x/Kconfig | 2 +-
drivers/media/platform/atmel/Kconfig | 4 +--
drivers/media/platform/blackfin/Kconfig | 1 -
drivers/media/platform/davinci/Kconfig | 6 ----
drivers/media/platform/marvell-ccic/Kconfig | 3 +-
drivers/media/platform/rcar-vin/Kconfig | 2 +-
drivers/media/platform/soc_camera/Kconfig | 3 +-
drivers/media/platform/sti/c8sectpfe/Kconfig | 2 +-
drivers/media/v4l2-core/Kconfig | 2 --
drivers/mmc/host/Kconfig | 10 ++-----
drivers/mtd/nand/Kconfig | 8 ++---
drivers/mtd/spi-nor/Kconfig | 2 +-
drivers/net/ethernet/amd/Kconfig | 2 +-
drivers/net/ethernet/apm/xgene-v2/Kconfig | 1 -
drivers/net/ethernet/apm/xgene/Kconfig | 1 -
drivers/net/ethernet/arc/Kconfig | 6 ++--
drivers/net/ethernet/broadcom/Kconfig | 2 --
drivers/net/ethernet/calxeda/Kconfig | 2 +-
drivers/net/ethernet/hisilicon/Kconfig | 2 +-
drivers/net/ethernet/marvell/Kconfig | 8 ++---
drivers/net/ethernet/mellanox/mlxsw/Kconfig | 2 +-
drivers/net/ethernet/renesas/Kconfig | 2 --
drivers/net/wireless/broadcom/brcm80211/Kconfig | 1 -
drivers/net/wireless/quantenna/qtnfmac/Kconfig | 2 +-
drivers/remoteproc/Kconfig | 1 -
drivers/scsi/hisi_sas/Kconfig | 2 +-
drivers/spi/Kconfig | 12 ++------
drivers/staging/media/davinci_vpfe/Kconfig | 1 -
drivers/staging/media/omap4iss/Kconfig | 1 -
drivers/staging/vc04_services/Kconfig | 1 -
drivers/tty/serial/Kconfig | 4 ---
drivers/usb/gadget/udc/Kconfig | 4 +--
drivers/usb/mtu3/Kconfig | 2 +-
drivers/video/fbdev/Kconfig | 3 +-
sound/soc/bcm/Kconfig | 3 +-
sound/soc/kirkwood/Kconfig | 1 -
sound/soc/pxa/Kconfig | 1 -
sound/soc/qcom/Kconfig | 7 ++---
55 files changed, 56 insertions(+), 143 deletions(-)

--
2.7.4

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds