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0ae653fbec
Currently we're calling btrfs_num_copies() before btrfs_get_chunk_map() in btrfs_map_block(). But btrfs_num_copies() itself does a chunk map lookup to be able to calculate the number of copies. So split out the code getting the number of copies from btrfs_num_copies() into a helper called btrfs_chunk_map_num_copies() and directly call it from btrfs_map_block() and btrfs_num_copies(). This saves us one rbtree lookup per btrfs_map_block() invocation. Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.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 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.