2022-04-22 18:24:23

by Tudor Ambarus

Subject: [PATCH 1/3] ARM: configs: at91: Remove MTD_BLOCK and use MTD_UBI_BLOCK for read only block FS

Using mtdblock on raw flashes is generally a bad idea as it lacks
wear-leveling, bad block handling or power-cut management.
What happens when you use mtdblock and you change any sector of your
mtdblockX device, is that it reads the whole corresponding eraseblock into
the memory, erases the eraseblock, changes the sector in RAM, and writes
the whole eraseblock back. If you have a power failure when the eraseblock
is being erased, you lose all the block device sectors in it. The flash
will likely decay soon because the eraseblocks will wear out.

Remove this archaic tool as its use case should rather be only for debug
purposes. This means that write-capable block file systems like ext2,
ext3, FAT, etc. will no longer be addressed with at91 defconfigs. For
read only block filesystems like SquashFS, use MTD_UBI_BLOCK instead and
benefit of UBI's bit-flip handling and wear-levelling.

Signed-off-by: Tudor Ambarus <[email protected]>
---
arch/arm/configs/at91_dt_defconfig | 2 +-
arch/arm/configs/sama5_defconfig | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/configs/at91_dt_defconfig b/arch/arm/configs/at91_dt_defconfig
index 549d01be0b47..cf79510631ea 100644
--- a/arch/arm/configs/at91_dt_defconfig
+++ b/arch/arm/configs/at91_dt_defconfig
@@ -50,13 +50,13 @@ CONFIG_DEVTMPFS_MOUNT=y
CONFIG_MTD=y
CONFIG_MTD_TESTS=m
CONFIG_MTD_CMDLINE_PARTS=y
-CONFIG_MTD_BLOCK=y
CONFIG_MTD_DATAFLASH=y
CONFIG_MTD_RAW_NAND=y
CONFIG_MTD_NAND_ATMEL=y
CONFIG_MTD_SPI_NOR=y
CONFIG_MTD_UBI=y
CONFIG_MTD_UBI_FASTMAP=y
+CONFIG_MTD_UBI_BLOCK=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_COUNT=4
diff --git a/arch/arm/configs/sama5_defconfig b/arch/arm/configs/sama5_defconfig
index 03dd80c2a19e..1c4c5a035518 100644
--- a/arch/arm/configs/sama5_defconfig
+++ b/arch/arm/configs/sama5_defconfig
@@ -57,13 +57,13 @@ CONFIG_DEVTMPFS_MOUNT=y
CONFIG_MTD=y
CONFIG_MTD_TESTS=m
CONFIG_MTD_CMDLINE_PARTS=y
-CONFIG_MTD_BLOCK=y
CONFIG_MTD_CFI=y
CONFIG_MTD_RAW_NAND=y
CONFIG_MTD_NAND_ATMEL=y
CONFIG_MTD_SPI_NOR=y
CONFIG_MTD_UBI=y
CONFIG_MTD_UBI_FASTMAP=y
+CONFIG_MTD_UBI_BLOCK=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_COUNT=4
--
2.25.1

2022-04-22 22:02:06

by Tudor Ambarus

Subject: [PATCH 2/3] ARM: configs: at91: sama7: Enable MTD_UBI_FASTMAP

Use fastmap to accelerate the attach procedure.

Signed-off-by: Tudor Ambarus <[email protected]>
---
arch/arm/configs/sama7_defconfig | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/configs/sama7_defconfig b/arch/arm/configs/sama7_defconfig
index 07b0494ef743..03652454274f 100644
--- a/arch/arm/configs/sama7_defconfig
+++ b/arch/arm/configs/sama7_defconfig
@@ -94,6 +94,7 @@ CONFIG_MTD_NAND_ATMEL=y
# CONFIG_MTD_NAND_ECC_SW_HAMMING is not set
CONFIG_MTD_SPI_NOR=y
CONFIG_MTD_UBI=y
+CONFIG_MTD_UBI_FASTMAP=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_COUNT=1
@@ -221,9 +222,9 @@ CONFIG_CRC_ITU_T=y
CONFIG_DMA_CMA=y
CONFIG_CMA_SIZE_MBYTES=32
CONFIG_CMA_ALIGNMENT=9
+# CONFIG_DEBUG_MISC is not set
# CONFIG_SECTION_MISMATCH_WARN_ONLY is not set
CONFIG_DEBUG_FS=y
-# CONFIG_DEBUG_MISC is not set
# CONFIG_SCHED_DEBUG is not set
CONFIG_STACKTRACE=y
# CONFIG_FTRACE is not set
--
2.25.1

2022-05-05 18:48:34

by Nicolas Ferre

Subject: Re: [PATCH 2/3] ARM: configs: at91: sama7: Enable MTD_UBI_FASTMAP

On 20/04/2022 at 15:47, Tudor Ambarus wrote:
> Use fastmap to accelerate the attach procedure.
>
> Signed-off-by: Tudor Ambarus <[email protected]>
> ---
> arch/arm/configs/sama7_defconfig | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/configs/sama7_defconfig b/arch/arm/configs/sama7_defconfig
> index 07b0494ef743..03652454274f 100644
> --- a/arch/arm/configs/sama7_defconfig
> +++ b/arch/arm/configs/sama7_defconfig
> @@ -94,6 +94,7 @@ CONFIG_MTD_NAND_ATMEL=y
> # CONFIG_MTD_NAND_ECC_SW_HAMMING is not set
> CONFIG_MTD_SPI_NOR=y
> CONFIG_MTD_UBI=y
> +CONFIG_MTD_UBI_FASTMAP=y
> CONFIG_BLK_DEV_LOOP=y
> CONFIG_BLK_DEV_RAM=y
> CONFIG_BLK_DEV_RAM_COUNT=1
> @@ -221,9 +222,9 @@ CONFIG_CRC_ITU_T=y
> CONFIG_DMA_CMA=y
> CONFIG_CMA_SIZE_MBYTES=32
> CONFIG_CMA_ALIGNMENT=9
> +# CONFIG_DEBUG_MISC is not set
> # CONFIG_SECTION_MISMATCH_WARN_ONLY is not set
> CONFIG_DEBUG_FS=y
> -# CONFIG_DEBUG_MISC is not set
> # CONFIG_SCHED_DEBUG is not set
> CONFIG_STACKTRACE=y
> # CONFIG_FTRACE is not set

I understand the rationale of this change, but it should probably go
into another patch or it's even sometimes done by arm-soc maintainers,
so I removed it.
No need to resend, I'll remove while applying.

Best regards,
Nicolas



--
Nicolas Ferre

2022-05-06 09:35:19

by Nicolas Ferre

Subject: Re: [PATCH 1/3] ARM: configs: at91: Remove MTD_BLOCK and use MTD_UBI_BLOCK for read only block FS

On 20/04/2022 at 15:47, Tudor Ambarus wrote:
> Using mtdblock on raw flashes is generally a bad idea as it lacks
> wear-leveling, bad block handling or power-cut management.
> What happens when you use mtdblock and you change any sector of your
> mtdblockX device, is that it reads the whole corresponding eraseblock into
> the memory, erases the eraseblock, changes the sector in RAM, and writes
> the whole eraseblock back. If you have a power failure when the eraseblock
> is being erased, you lose all the block device sectors in it. The flash
> will likely decay soon because the eraseblocks will wear out.
>
> Remove this archaic tool as its use case should rather be only for debug
> purposes. This means that write-capable block file systems like ext2,
> ext3, FAT, etc. will no longer be addressed with at91 defconfigs. For
> read only block filesystems like SquashFS, use MTD_UBI_BLOCK instead and
> benefit of UBI's bit-flip handling and wear-levelling.
>
> Signed-off-by: Tudor Ambarus <[email protected]>

For the whole series:
Acked-by: Nicolas Ferre <[email protected]>

and queued in at91-defconfig for 5.19.

Best regards,
Nicolas

> ---
> arch/arm/configs/at91_dt_defconfig | 2 +-
> arch/arm/configs/sama5_defconfig | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/configs/at91_dt_defconfig b/arch/arm/configs/at91_dt_defconfig
> index 549d01be0b47..cf79510631ea 100644
> --- a/arch/arm/configs/at91_dt_defconfig
> +++ b/arch/arm/configs/at91_dt_defconfig
> @@ -50,13 +50,13 @@ CONFIG_DEVTMPFS_MOUNT=y
> CONFIG_MTD=y
> CONFIG_MTD_TESTS=m
> CONFIG_MTD_CMDLINE_PARTS=y
> -CONFIG_MTD_BLOCK=y
> CONFIG_MTD_DATAFLASH=y
> CONFIG_MTD_RAW_NAND=y
> CONFIG_MTD_NAND_ATMEL=y
> CONFIG_MTD_SPI_NOR=y
> CONFIG_MTD_UBI=y
> CONFIG_MTD_UBI_FASTMAP=y
> +CONFIG_MTD_UBI_BLOCK=y
> CONFIG_BLK_DEV_LOOP=y
> CONFIG_BLK_DEV_RAM=y
> CONFIG_BLK_DEV_RAM_COUNT=4
> diff --git a/arch/arm/configs/sama5_defconfig b/arch/arm/configs/sama5_defconfig
> index 03dd80c2a19e..1c4c5a035518 100644
> --- a/arch/arm/configs/sama5_defconfig
> +++ b/arch/arm/configs/sama5_defconfig
> @@ -57,13 +57,13 @@ CONFIG_DEVTMPFS_MOUNT=y
> CONFIG_MTD=y
> CONFIG_MTD_TESTS=m
> CONFIG_MTD_CMDLINE_PARTS=y
> -CONFIG_MTD_BLOCK=y
> CONFIG_MTD_CFI=y
> CONFIG_MTD_RAW_NAND=y
> CONFIG_MTD_NAND_ATMEL=y
> CONFIG_MTD_SPI_NOR=y
> CONFIG_MTD_UBI=y
> CONFIG_MTD_UBI_FASTMAP=y
> +CONFIG_MTD_UBI_BLOCK=y
> CONFIG_BLK_DEV_LOOP=y
> CONFIG_BLK_DEV_RAM=y
> CONFIG_BLK_DEV_RAM_COUNT=4


--
Nicolas Ferre