Re: [PATCH V15 14/18] block: enable multipage bvecs

Hi Ming,

On 2019-02-28 00:29, Ming Lei wrote:

On Wed, Feb 27, 2019 at 08:47:09PM +0000, Jon Hunter wrote:

quoted

On 21/02/2019 08:42, Marek Szyprowski wrote:

quoted

On 2019-02-15 12:13, Ming Lei wrote:

quoted

This patch pulls the trigger for multi-page bvecs.

Reviewed-by: Omar Sandoval <redacted>
Signed-off-by: Ming Lei <redacted>

Since Linux next-20190218 I've observed problems with block layer on one
of my test devices (Odroid U3 with EXT4 rootfs on SD card). Bisecting
this issue led me to this change. This is also the first linux-next
release with this change merged. The issue is fully reproducible and can
be observed in the following kernel log:

sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
s3c-sdhci 12530000.sdhci: clock source 2: mmc_busclk.2 (100000000 Hz)
s3c-sdhci 12530000.sdhci: Got CD GPIO
mmc0: SDHCI controller on samsung-hsmmc [12530000.sdhci] using ADMA
mmc0: new high speed SDHC card at address aaaa
mmcblk0: mmc0:aaaa SL16G 14.8 GiB

I have also noticed some failures when writing to an eMMC device on one
of our Tegra boards. We have a simple eMMC write/read test and it is
currently failing because the data written does not match the source.

I did not seem the same crash as reported here, however, in our case the
rootfs is NFS mounted and so probably would not. However, the bisect
points to this commit and reverting on top of -next fixes the issues.

It is sdhci, probably related with max segment size, could you test the
following patch:

https://marc.info/?l=linux-mmc&m=155128334122951&w=2

This seems to be fixing my issue too! Thanks!

It also fixed the boot issue from USB stick (Exynos EHCI / Mass
Storage), but I suspect that reading the partition table from the sd
card (which hold the bootloader and thus must be present to boot the
device) was enough to trash memory/page cache and break the boot process.

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland