Linux has a header file that defines an ilog2 function and some simple
functions/macros that use it: roundup_pow_of_two, is_power_of_2,
rounddown_pow_of_two, and order_base_2. This change moves three of
those simple functions (all but is_power_of_2) from linuxkpi to
libkern. It also deletes a few implementations of these functions
that have previously been copied into code for various device drivers,
so that they can use the libkern version. The is_power_of_2 macro was
not moved because powerof2 in param.h provides almost the same service
already (except that they disagree about whether 0 is a power of two).
Since the linux definitions of these functions were copied into
FreeBSD 11 years ago, linux has improved them, and this change
provides those improvements. In particular, a giant table of log
values for evaluating ilog2 for constant values is no longer
necessary.
Reviewed by: alc, markj (previous version)
Differential Revision: https://reviews.freebsd.org/D45536
(cherry picked from commit c8b0c33b03ac072413b27bed2bdae2ae27426f3a)
The kernel source contains several definitions of an ilog2 function;
some are slower than necessary, and one of them is incorrect.
Elimininate them all and define an ilog2 macro in libkern to replace
them, in a way that is fast, correct for all argument types, and, in a
GENERIC kernel, includes a check for an invalid zero parameter.
Folks at Microsoft have verified that having a correct ilog2
definition for their MANA driver doesn't break it.
Reviewed by: alc, markj, mhorne (older version), jhibbits (older version)
Differential Revision: https://reviews.freebsd.org/D45170
Differential Revision: https://reviews.freebsd.org/D45235
(cherry picked from commit b0056b31e90029553894d17c441cbb2c06d31412)
- Move all files related to the LinuxKPI into sys/compat/linuxkpi and
its subfolders.
- Update sys/conf/files and some Makefiles to use new file locations.
- Added description of COMPAT_LINUXKPI to sys/conf/NOTES which in turn
adds the LinuxKPI to all LINT builds.
- The LinuxKPI can be added to the kernel by setting the
COMPAT_LINUXKPI option. The OFED kernel option no longer builds the
LinuxKPI into the kernel. This was done to keep the build rules for
the LinuxKPI in sys/conf/files simple.
- Extend the LinuxKPI module to include support for USB by moving the
Linux USB compat from usb.ko to linuxkpi.ko.
- Bump the FreeBSD_version.
- A universe kernel build has been done.
Reviewed by: np @ (cxgb and cxgbe related changes only)
Sponsored by: Mellanox Technologies
2015-10-29 08:28:39 +00:00
Renamed from sys/ofed/include/linux/log2.h (Browse further)
