On Thu, Oct 25, 2018 at 05:09:32PM +0100, Rui Salvaterra wrote:

Hi,

After commit 744889b7cbb56a64f957e65ade7cb65fe3f35714, I started
getting this (-EIO, it seems) on my dmesg:

swapon: discard_swap(00000000c275f02d): -5

This is an 8 GB zram swap device. It's configured like this:

modprobe zram
echo zstd > /sys/block/zram0/comp_algorithm
echo 8297508864 > /sys/block/zram0/disksize
mkswap /dev/zram0
swapon -d -p 100 /dev/zram0

I should note that if I use --discard=pages instead of -d (both
policies) at swapon, I don't get this error.
Reverting the commit from v4.19 final fixes the error for me, but
surely breaks something else. :)
Let me know if you need any additional information.

The patch titled with 'block: make sure discard bio is aligned with logical block size'
in the list may fix this issue, please test and see if it works.

Thanks,
Ming