[PATCH 0/6] mmc: Set PROBE_PREFER_ASYNCHRONOUS for all host drivers

[Ulf Hansson]

On Fri, 4 Sep 2020 at 01:25, Douglas Anderson <dianders at chromium.org> wrote:
>
> As per discussion [1], it seems like it should be quite safe to turn
> on PROBE_PREFER_ASYNCHRONOUS for all sd/mmc host controllers.  Let's
> give it a shot.  For some discussion about this flag, see the commit
> message for commit 3d3451124f3d ("mmc: sdhci-msm: Prefer asynchronous
> probe").
>
> I've broken this series into chunks based on LTS kernel releases to
> attempt to make it easier if someone wanted to cherry-pick it to an
> older kernel.  While these cherry-picks won't be conflict free, there
> should only be trivial context conflicts and no problems with drivers
> that are totally missing.  This is a bit of a compromise between a
> 1-big patch and a many-part patch series.
>
> I have only tested this on a rk3399-kevin (sdhci-of-arasan) and a
> rk3288-veyron (dw_mmc-rockchip) device and only lightly.  If this
> patch causes anyone problems those drivers should be marked with
> PROBE_FORCE_SYNCHRONOUS, debugged, and then go back to prefer
> asynchronous.  Any problems are likely just a hidden bug that has been
> exposed by this change.
>
> NOTE: in theory, it'd be nice if there was a KConfig option that we
> could flip that would turn on async probe everywhere (except for those
> that opt out by adding PROBE_FORCE_SYNCHRONOUS).  My hope is that by
> adding this flag in more places it will become clear that this flag is
> working reliably and easier to move over when we're ready.
>
> While coccinelle is too difficult for my feeble brain, I managed to
> whip up a pretty terrible python script to help with this.  For your
> edification:
>
> import os
> import sys
> import re
>
> for filename in os.listdir("."):
>     found_plat = False
>     found_driver = False
>     output = []
>     for line in open(filename, "r").readlines():
>         output.append(line)
>
>         if "struct platform_driver" in line:
>             found_plat = True
>         if found_plat and re.search(r"\t\.driver\s*=\s*{", line):
>             found_driver = True
>             found_plat = False
>         mo = re.search(r"(\s*)\.name(\s*)=", line)
>         if found_driver and mo:
>             if mo.group(2) == " ":
>                 space = " "
>             elif mo.group(2) == "\t":
>                 # Best we can do
>                 space = " "
>             elif mo.group(2).startswith("\t"):
>                 # Guess that removing one tab is right
>                 space = mo.group(2)[1:]
>             else:
>                 # Guess it's all spaces
>                 space = mo.group(2)[7:] + " "
>
>             output.append("%s.probe_type%s= PROBE_PREFER_ASYNCHRONOUS,\n" % (mo.group(1), space))
>             found_driver = False
>
>     open(filename, "w").write("".join(output))
>
> [1] https://lore.kernel.org/r/CAPDyKFq31bucJhP9hp1HSqh-qM2uNGHgDoyQpmbJf00nEf_T4Q@mail.gmail.com/
>
>
> Douglas Anderson (6):
>   mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v4.4
>   mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v4.9
>   mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v4.14
>   mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v4.19
>   mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v5.4
>   mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that are newer than 5.4
>
>  drivers/mmc/host/alcor.c                      | 1 +
>  drivers/mmc/host/android-goldfish.c           | 1 +
>  drivers/mmc/host/atmel-mci.c                  | 1 +
>  drivers/mmc/host/au1xmmc.c                    | 1 +
>  drivers/mmc/host/bcm2835.c                    | 1 +
>  drivers/mmc/host/cavium-octeon.c              | 1 +
>  drivers/mmc/host/davinci_mmc.c                | 1 +
>  drivers/mmc/host/dw_mmc-bluefield.c           | 1 +
>  drivers/mmc/host/dw_mmc-exynos.c              | 1 +
>  drivers/mmc/host/dw_mmc-hi3798cv200.c         | 1 +
>  drivers/mmc/host/dw_mmc-k3.c                  | 1 +
>  drivers/mmc/host/dw_mmc-pltfm.c               | 1 +
>  drivers/mmc/host/dw_mmc-rockchip.c            | 1 +
>  drivers/mmc/host/dw_mmc-zx.c                  | 1 +
>  drivers/mmc/host/jz4740_mmc.c                 | 1 +
>  drivers/mmc/host/meson-gx-mmc.c               | 1 +
>  drivers/mmc/host/meson-mx-sdhc-mmc.c          | 1 +
>  drivers/mmc/host/meson-mx-sdio.c              | 1 +
>  drivers/mmc/host/moxart-mmc.c                 | 1 +
>  drivers/mmc/host/mtk-sd.c                     | 1 +
>  drivers/mmc/host/mvsdio.c                     | 1 +
>  drivers/mmc/host/mxcmmc.c                     | 1 +
>  drivers/mmc/host/mxs-mmc.c                    | 1 +
>  drivers/mmc/host/omap.c                       | 1 +
>  drivers/mmc/host/omap_hsmmc.c                 | 1 +
>  drivers/mmc/host/owl-mmc.c                    | 1 +
>  drivers/mmc/host/pxamci.c                     | 1 +
>  drivers/mmc/host/renesas_sdhi_internal_dmac.c | 1 +
>  drivers/mmc/host/renesas_sdhi_sys_dmac.c      | 1 +
>  drivers/mmc/host/rtsx_pci_sdmmc.c             | 1 +
>  drivers/mmc/host/rtsx_usb_sdmmc.c             | 1 +
>  drivers/mmc/host/s3cmci.c                     | 1 +
>  drivers/mmc/host/sdhci-acpi.c                 | 1 +
>  drivers/mmc/host/sdhci-bcm-kona.c             | 1 +
>  drivers/mmc/host/sdhci-brcmstb.c              | 1 +
>  drivers/mmc/host/sdhci-cadence.c              | 1 +
>  drivers/mmc/host/sdhci-cns3xxx.c              | 1 +
>  drivers/mmc/host/sdhci-dove.c                 | 1 +
>  drivers/mmc/host/sdhci-esdhc-imx.c            | 1 +
>  drivers/mmc/host/sdhci-esdhc-mcf.c            | 1 +
>  drivers/mmc/host/sdhci-iproc.c                | 1 +
>  drivers/mmc/host/sdhci-milbeaut.c             | 1 +
>  drivers/mmc/host/sdhci-of-arasan.c            | 1 +
>  drivers/mmc/host/sdhci-of-aspeed.c            | 2 ++
>  drivers/mmc/host/sdhci-of-at91.c              | 1 +
>  drivers/mmc/host/sdhci-of-dwcmshc.c           | 1 +
>  drivers/mmc/host/sdhci-of-esdhc.c             | 1 +
>  drivers/mmc/host/sdhci-of-hlwd.c              | 1 +
>  drivers/mmc/host/sdhci-of-sparx5.c            | 1 +
>  drivers/mmc/host/sdhci-omap.c                 | 1 +
>  drivers/mmc/host/sdhci-pic32.c                | 1 +
>  drivers/mmc/host/sdhci-pxav2.c                | 1 +
>  drivers/mmc/host/sdhci-pxav3.c                | 1 +
>  drivers/mmc/host/sdhci-s3c.c                  | 1 +
>  drivers/mmc/host/sdhci-sirf.c                 | 1 +
>  drivers/mmc/host/sdhci-spear.c                | 1 +
>  drivers/mmc/host/sdhci-sprd.c                 | 1 +
>  drivers/mmc/host/sdhci-st.c                   | 1 +
>  drivers/mmc/host/sdhci-tegra.c                | 1 +
>  drivers/mmc/host/sdhci-xenon.c                | 1 +
>  drivers/mmc/host/sdhci_am654.c                | 1 +
>  drivers/mmc/host/sdhci_f_sdh30.c              | 1 +
>  drivers/mmc/host/sh_mmcif.c                   | 1 +
>  drivers/mmc/host/sunxi-mmc.c                  | 1 +
>  drivers/mmc/host/tmio_mmc.c                   | 1 +
>  drivers/mmc/host/uniphier-sd.c                | 1 +
>  drivers/mmc/host/usdhi6rol0.c                 | 1 +
>  drivers/mmc/host/wbsd.c                       | 1 +
>  drivers/mmc/host/wmt-sdmmc.c                  | 1 +
>  69 files changed, 70 insertions(+)
>
> --
> 2.28.0.526.ge36021eeef-goog
>

An interesting idea about a patch per LTS release. I think it makes
perfect sense in this type of case.

Let's give this a shot in next and see how it goes. So, applied for
next, thanks!

Kind regards
Uffe