Re: [PATCH v7 1/6] zswap: fix writeback lock ordering for zsmalloc

[Sergey Senozhatsky]

On (22/11/28 11:16), Nhat Pham wrote:
> zswap's customary lock order is tree->lock before pool->lock, because
> the tree->lock protects the entries' refcount, and the free callbacks in
> the backends acquire their respective pool locks to dispatch the backing
> object. zsmalloc's map callback takes the pool lock, so zswap must not
> grab the tree->lock while a handle is mapped. This currently only
> happens during writeback, which isn't implemented for zsmalloc. In
> preparation for it, move the tree->lock section out of the mapped entry
> section
> 
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx>

Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>