[PATCH v3 0/3] mtd: write support for minor-aligned partitions

[Thibaut VARÈNE]

Hi,

Since there were no objections in the past week, could you please consider merging this patch series?

Thanks,
Thibaut

> Le 29 juil. 2022 à 11:16, Thibaut VARÈNE <hacks+kernel at slashdirt.org> a écrit :
> 
> This patch series enable write support for minor-aligned mtd partitions
> on devices that support multiple erasesizes.
> 
> On supporting hardware, they enable RW operations on mtd partitions that
> break "major" (largest) erasesize boundary (e.g. too small or not
> correctly aligned) without sacrificing performance (i.e. forcing
> everything to use 4K sectors). Finally, they address an historical FIXME
> in mtdpart.c.
> 
> The following performance numbers were measured with v5.10 kernel on OpenWrt:
> (CONFIG_MTD_SPI_NOR_USE_VARIABLE_ERASE=y forces the use of the new code path)
> 
> OpenWrt 5.10 ramips MT7621 w25q128jv 0xfc0000 firmware partition length
> time mtd erase firmware
> 
> Without this patch:
> MTD_SPI_NOR_USE_4K_SECTORS=n	|y
> real    0m 50.86s		|2m 11.66s
> user    0m 0.00s		|0m 0.00s
> sys     0m 50.80s		|1m 56.20s
> can write minor-aligned parts? N|Y
> 
> With this patch:
> MTD_SPI_NOR_USE_VARIABLE_ERASE=n|y		|4K_SECTORS=y
> real    0m 51.68s		|0m 50.85s	|2m 12.89s
> user    0m 0.00s		|0m 0.00s	|0m 0.01s
> sys     0m 46.94s		|0m 50.38s	|2m 12.46s
> can write minor-aligned parts? N|Y		|Y
> 
> 
> NB: This patchset was previously submitted as a monolithic patch (RFC[0],
> v1[1]). While not submitted upstream v2 was however reviewed, tested and
> accepted in OpenWrt, and backported into the upcoming 22.03 stable branch:
> https://github.com/openwrt/openwrt/pull/3271
> 
> [0] 20210104122853.18428-1-git at johnthomson.fastmail.com.au
> [1] 20210608040719.14431-1-git at johnthomson.fastmail.com.au
> 
> Changes v2 -> v3:
>  - Split patch into incremental, functionally-separate changes.
>  - Adjusted erasesize_minor assignment check in spi-nor/core.c
>  - Addressed checkpatch warning on "printk(KERN_WARNING..."
>  - Documented new sysfs attribute
> 
> Changes v1 -> v2:
>  - Added mtdcore sysfs attribute for erasesize_minor
>  - Removed finding minor erasesize for variable erase regions device,
>    (untested and no response to RFC).
>  - Moved IF_ENABLED() to guard setting erasesize_minor in spi-nor/core.c
>  - Removed setting major erasesize to minor where partition boundaries
>    require minor erase to be writable
>  - Simplified minor boundary check by relying on minor being a factor
>    of major
> 
> Changes RFC -> v1:
>  - Fixed uninitialized variable smatch warning
> 
> Thibaut VARÈNE (3):
>  mtd: mtdpart: write support for minor-aligned partitions
>  mtd: spi-nor: set erasesize_minor in spi_nor_select_erase()
>  mtd: spi-nor: allow overriding uniform erase
> 
> Documentation/ABI/testing/sysfs-class-mtd |  8 ++++++
> drivers/mtd/mtdcore.c                     | 10 +++++++
> drivers/mtd/mtdpart.c                     | 35 ++++++++++++++++-------
> drivers/mtd/spi-nor/Kconfig               | 10 +++++++
> drivers/mtd/spi-nor/core.c                | 13 +++++++--
> include/linux/mtd/mtd.h                   |  2 ++
> 6 files changed, 65 insertions(+), 13 deletions(-)
> 
> 
> base-commit: e0dccc3b76fb35bb257b4118367a883073d7390e
> -- 
> 2.30.2
>