[PATCH v6 0/3] Implement readahead for squashfs

[Hsin-Yi Wang <hsinyi@chromium.org>]

Commit 9eec1d897139("squashfs: provide backing_dev_info in order to
disable read-ahead") mitigates the performance drop issue for squashfs
by closing readahead for it.

This series implements readahead callback for squashfs. The previous
discussions are in [1] and [2].

[1]
https://lore.kernel.org/all/CAJMQK-g9G6KQmH-V=BRGX0swZji9Wxe_2c7ht-MMAapdFy2pXw@mail.gmail.com/T/
[2]
https://lore.kernel.org/linux-mm/Yn5Yij9pRPCzDozt@casper.infradead.org/t/#m4af4473b94f98a4996cb11756b633a07e5e059d1

This version is based on next-20220610 and the following series:
"Squashfs: handle missing pages decompressing into page cache" [3].

This version is a refresh of ca1505bf4805 ("squashfs: implement
readahead") and 9d58b94aa73a ("squashfs: always build "file direct"
version of page actor").

There's no change in 4af2bd190a5b7 (Revert "squashfs: provide
backing_dev_info in order to disable read-ahead"), but it's carried in
this version too for consistency.

[3]
https://patchwork.kernel.org/project/linux-mm/cover/20220611032133.5743-1-phillip@squashfs.org.uk/

Hsin-Yi Wang (2):
  Revert "squashfs: provide backing_dev_info in order to disable
    read-ahead"
  squashfs: implement readahead

Phillip Lougher (1):
  squashfs: always build "file direct" version of page actor

 fs/squashfs/Makefile     |  4 +-
 fs/squashfs/file.c       | 92 +++++++++++++++++++++++++++++++++++++++-
 fs/squashfs/page_actor.h | 46 --------------------
 fs/squashfs/super.c      | 33 --------------
 4 files changed, 93 insertions(+), 82 deletions(-)

-- 
2.36.1.476.g0c4daa206d-goog