Qu Wenruo aa60fe12b4 btrfs: zlib: refactor S390x HW acceleration buffer preparation
Currently for s390x HW zlib compression, to get the best performance we
need a buffer size which is larger than a page.

This means we need to copy multiple pages into workspace->buf, then use
that buffer as zlib compression input.

Currently it's hardcoded using page sized folio, and all the handling
are deep inside a loop.

Refactor the code by:

- Introduce a dedicated helper to do the buffer copy
  The new helper will be called copy_data_into_buffer().

- Add extra ASSERT()s
  * Make sure we only go into the function for hardware acceleration
  * Make sure we still get page sized folio

- Prepare for future large folios
  This means we will rely on the folio size, other than PAGE_SIZE to do
  the copy.

- Handle the folio mapping and unmapping inside the helper function
  For S390x hardware acceleration case, it never utilize the @data_in
  pointer, thus we can do folio mapping/unmapping all inside the function.

Acked-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Tested-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-03-18 20:35:41 +01:00
2024-09-01 20:43:24 -07:00
2025-02-04 11:27:45 -05:00
2022-09-28 09:02:20 +02:00
2025-03-16 12:55:17 -10:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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