kmod 30

• Improvements

  • Stop adding duplicate information on modules.builtin.alias.bin, just use
    the modules.builtin.bin index

  • Speedup depmod, particularly under qemu with emulated arch, by
    avoiding a lot of open/read/close of modules.alias.bin. On an
    emulated ARM rootfs, depmod with only 2 modules was taking ~32s
    vs ~0.07s now.

  • Add kmod_module_new_from_name_lookup() which allows doing a lookup by
    module name, without considering the aliases. Other than that search
    order is similar to kmod_module_new_from_lookup().

  • modinfo learned the --modname option to explicitely show information
    about the module, even if there is an alias with the same name. This
    allows showing information about e.g. kernel/lib/crc32.ko, even if
    kernel also exports a crc32 alias in modules.alias:

            alias crc32 crc32_pclmul
            alias crc32 crc32_generic
    
      Same behavior will be used to other modules and to aliases provided
      by user/distro.
    

  • depmod.conf learned a new "excludedir" directive so distro/user can
    configure more directories to be excluded from its search, besides
    the hardcoded values "build" and "source".

  • Better group modprobe options on help output under "Management, Query and General".

  • modprobe learned a --wait option to be used together with -r
    when removing a module. This allows modprobe to keep trying the
    removal if it fails because the module is still in use. An exponential backoff
    time is used for further retries.
    The wait behavior provided by the kernel when not passing O_NONBLOCK
    to delete_module() was removed in v3.13 due to not be used and the
    consequences of having to support it in the kernel. However there may
    be some users, particularly on testsuites for individual susbsystems, that
    would want that. So provide a userspace implementation inside modprobe for
    such users. "rmmod" doesn't have a --wait as it remains a bare minimal over
    the API provided by the kernel. In future the --wait behavior can be added
    to libkmod for testsuites not exec'ing modprobe for module removal.

  • kmod_module_remove_module() learned a new flag to silence output when
    caller wants to handle them - this is particularly important for the
    --wait flag to modprobe, as it's not desired to keep seeing error messages
    while waiting for the module to be unused.

  • Add SM3 hash algo support to modinfo output, as already available in the kernel.

• Bug Fixes

  • Fix modinfo output when showing information for a .ko module when running
    on a kernel that has that module as builtin.

  • Fix kmod_module_new_from_lookup() returning > 0 rather than 0
    when it matches an alias.

  • Fix modinfo segfault when module doesn't exist.

  • Add missing function in the html documentation: kmod_get_dirname().

  • Fix modprobe incorrectly handling number of arguments when prepending values from
    MODPROBE_OPTIONS environment variable.

  • Fix modprobe -r --remove-dependencies and since "dependencies" was a
    misnomer, add the preferred argument option: "--remove-holders". This
    is the same name used by the kernel. It allows users to also remove
    other modules holding the one that is being removed.

  • Fix off-by-one in max module name length in depmod.

• Infra/internal

  • Start some changes in the out-of-tree test modules in kmod so they are useful
    for being really inserted in the kernel rather than relying on kmod's mock
    interface. This helps manual testing and may be used to exercise to test
    changes in the kernel.