[PATCH 0/4] checkpatch: skip more kernel-only checks for userspace code

[Kir Kolyshkin <kolyshkin@gmail.com>]

Commit 99b70ece33d8 ("checkpatch: suppress strscpy warnings for
userspace tools") added is_userspace() to skip checks which only make
sense for the kernel. This series extends that to a few more checks
which produce false positives for userspace code under tools/:

 - ENOSYS: the "ENOSYS means invalid syscall nr" rule is about the
   kernel ABI; in userspace, errno == ENOSYS is the standard way to
   detect a missing syscall (e.g. to skip a selftest on older kernels);
 - AVOID_BUG: "Do not crash the kernel" does not apply to userspace,
   where BUG()/BUG_ON() are assert-like shims;
 - SSCANF_TO_KSTRTO: kstrto<type> is not available in userspace.

Running "checkpatch.pl -f" (with --strict for AVOID_BUG, which is
a CHECK in file mode) on the files under tools/ that use ENOSYS, BUG()
or sscanf() gives 699 such warnings before this series (ENOSYS: 188,
AVOID_BUG: 491, SSCANF_TO_KSTRTO: 20), and none after.

Since tools/ also contains some kernel code (test modules, Kbuild-built
mocks, rvgen templates), patch 1 makes is_userspace() return false for
those locations, so they are still subject to all the kernel checks
(this also applies to the existing strcpy/strlcpy/strncpy checks).

Kir Kolyshkin (4):
  checkpatch: is_userspace: exclude kernel code under tools/
  checkpatch: don't warn about ENOSYS in userspace code
  checkpatch: don't warn about BUG() in userspace code
  checkpatch: don't suggest kstrto<type> in userspace code

 scripts/checkpatch.pl | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)


base-commit: f47d223627f80cb7a1eb14c585fe6cb35de5e984
-- 
2.56.0