Re: [PATCH 0/5] Fix rhashtable bit-locking for m68k

From: Guenter Roeck
Date: Fri Apr 12 2019 - 14:08:47 EST


On 4/11/19 6:52 PM, NeilBrown wrote:
As reported by Guenter Roeck, the new rhashtable bit-locking
doesn't work on m68k as it only requires 2-byte alignment, so BIT(1)
is addresses is not unused.

We current use BIT(0) to identify a NULLS marker, but that is only
needed in ->next pointers. The bucket head does not need a NULLS
marker, so the lsb there can be used for locking.

the first 4 patches make some small improvements and re-arrange some
code. The final patch converts to using only BIT(0) for these two
different special purposes.

I had previously suggested dropping the series until I fix it. Given
that this was fairly easy, I retract that I think it best simply to
add these patches to fix the code.

For the series:

Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Tested with the series applied on top of next-20190412, running all
345 qemu tests. No boot failures or new warnings observed.

Guenter