mm: zswap: zswap_store_page() will initialize entry after adding to xarray.

This incorporates Yosry's suggestions in [1] for further simplifying
zswap_store_page().  If the page is successfully compressed and added to
the xarray, we get the pool/objcg refs, and initialize all the entry's
members.  Only after this, we add it to the zswap LRU.

In the time between the entry's addition to the xarray and it's member
initialization, we are protected against concurrent stores/loads/swapoff
through the folio lock, and are protected against writeback because the
entry is not on the LRU yet.

This way, we don't have to drop the pool/objcg refs, now that the entry
initialization is centralized to the successful page store code path.

zswap_compress() is modified to take a zswap_pool parameter in keeping
with this simplification (as against obtaining this from entry->pool).

[1]: https://lore.kernel.org/all/CAJD7tkZh6ufHQef5HjXf_F5b5LC1EATexgseD=4WvrO+a6Ni6w@mail.gmail.com/

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kanchana P Sridhar <[email protected]>
Cc: Chengming Zhou <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Nhat Pham <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Wajdi Feghali <[email protected]>
Cc: Yosry Ahmed <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions