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In function btrfs_bg_flags_to_raid_index(), we use quite some if () to convert the BTRFS_BLOCK_GROUP_* bits to a index number. But the truth is, there is really no such need for so many branches at all. Since all BTRFS_BLOCK_GROUP_* flags are just one single bit set inside BTRFS_BLOCK_GROUP_PROFILES_MASK, we can easily use ilog2() to calculate their values. This calculation has an anchor point, the lowest PROFILE bit, which is RAID0. Even it's fixed on-disk format and should never change, here I added extra compile time checks to make it super safe: 1. Make sure RAID0 is always the lowest bit in PROFILE_MASK This is done by finding the first (least significant) bit set of RAID0 and PROFILE_MASK & ~RAID0. 2. Make sure RAID0 bit set beyond the highest bit of TYPE_MASK Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.