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Qu Wenruo
cb22964f1d
[BACKGROUND] Currently we handle extent bitmaps manually in extent_buffer_bitmap_set() and extent_buffer_bitmap_clear(). Although with various helpers like eb_bitmap_offset() it's still a little messy to read. The code seems to be a copy of bitmap_set(), but with all the cross-page handling embedded into the code. [ENHANCEMENT] This patch would enhance the readability by introducing two helpers: - memset_extent_buffer() To handle the byte aligned range, thus all the cross-page handling is done there. - extent_buffer_get_byte() This for the first and the last byte operations, which only need to grab one byte, thus no need for any cross-page handling. So we can split both extent_buffer_bitmap_set() and extent_buffer_bitmap_clear() into 3 parts: - Handle the first byte If the range fits inside the first byte, we can exit early. - Handle the byte aligned part This is the part which can have cross-page operations, and it would be handled by memset_extent_buffer(). - Handle the last byte This refactoring does not only make the code a little easier to read, but also makes later folio/page switch much easier, as the switch only needs to be done inside memset_extent_buffer() and extent_buffer_get_byte(). Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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 Restructured Text 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.