mm: zswap: move more same-filled pages checks outside of zswap_store()

Currently, zswap_store() checks zswap_same_filled_pages_enabled, kmaps the
folio, then calls zswap_is_page_same_filled() to check the folio contents.
Move this logic into zswap_is_page_same_filled() as well (and rename it
to use 'folio' while we are at it).

This makes zswap_store() cleaner, and makes following changes to that
logic contained within the helper.

While we are at it:
- Rename the insert_entry label to store_entry to match xa_store().
- Add comment headers for same-filled functions and the main API
  functions (load, store, invalidate, swapon, swapoff).

No functional change intended.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Yosry Ahmed <[email protected]>
Reviewed-by: Nhat Pham <[email protected]>
Reviewed-by: Chengming Zhou <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: "Maciej S. Szmigiero" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions