[PATCH v5 00/12] seq_buf: Add seq_buf_strlen()

[Kees Cook]

Hi,

While working on seq_buf conversions[1], we found there was a need for
seq_buf_strlen() (since calling strlen(seq_buf_str()) would be a waste
of time: seq_buf already knows the length), seq_buf_init_append() (to
start a seq_buf from an existing string buffer), and seq_buf_terminate()
(as there are many callers using seq_buf_str() just for its termination
side-effect). And while implementing that, we found a bunch of other
related things that needed fixing. This is that ever-growing series,
with tests for each fix.

 v5:
  - add Alexei's Acked-by for the bpf bits (07/12, 08/12)
  - 03/12: new: lpfc_rx_monitor_report() drops a record that does not
    fit itself, instead of relying on seq_buf_puts() leaving it out,
    which 04/12 changes (BPF CI)
  - 04/12: note the audit of seq_buf_puts() and seq_buf_putmem() callers
    in the commit message (BPF CI)
  - 04/12, 05/12: drop the inaccurate "unlike the other writers" from
    the export notes (BPF CI)
  - 05/12: drop a duplicate #include from the tests
  - 06/12: note in seq_buf_str()'s kernel-doc that only a zero-sized
    seq_buf returns the static empty string (Andy)
  - 07/12: write the seq_buf_terminate() test data with
    seq_buf_putmem(), which leaves no NUL, so the test fails if
    seq_buf_terminate() does nothing (Sashiko)
  - 09/12: fix the commit message's description of seq_buf_init(), which
    empties the buffer rather than setting its size to 0 (BPF CI)
  - 09/12: check the length in the test of a string longer than the
    size, so an unbounded scan fails it (Sashiko)
  - v4..v5 diff: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/diff/?id=dev/v7.3-rc2/seq_buf/v5&id2=dev/v7.3-rc2/seq_buf/v4
 v4: https://lore.kernel.org/all/20261003035906.too.263-kees@xxxxxxxxxx/
 v3: https://lore.kernel.org/all/20260930235231.out.387-kees@xxxxxxxxxx/
 v2: https://lore.kernel.org/all/20260919002658.stay.929-kees@xxxxxxxxxx/
 v1: https://lore.kernel.org/all/20260917002312.i.923-kees@xxxxxxxxxx/

Thanks!

-Kees

[1] https://lore.kernel.org/all/20260917011359.1585961-1-morbo@xxxxxxxxxx/

Bill Wendling (1):
  seq_buf: Add seq_buf_init_append()

Kees Cook (11):
  seq_buf: Do not print an empty line from an overflowed
    seq_buf_do_printk()
  seq_buf: Do not pop from an overflowed seq_buf
  scsi: lpfc: Print rx monitor records straight into the seq_buf
  seq_buf: Copy what fits when seq_buf_puts() and seq_buf_putmem()
    overflow
  seq_buf: Clear what a writer did not claim when a seq_buf overflows
  seq_buf: Add seq_buf_strlen()
  seq_buf: Add seq_buf_terminate()
  bpf: Remove dead newline stripping from format_disasm_line()
  powerpc/papr_scm: Return the string length from the sysfs show
    functions
  nvdimm: ndtest: Return the string length from flags_show()
  docs: core-api: Document the seq_buf API

 Documentation/core-api/kernel-api.rst     |   9 +
 include/linux/seq_buf.h                   | 141 +++++-
 include/linux/trace_seq.h                 |   5 +-
 arch/powerpc/platforms/pseries/papr_scm.c |   6 +-
 drivers/scsi/lpfc/lpfc_sli.c              |  45 +-
 kernel/bpf/diagnostics.c                  |   8 +-
 kernel/trace/trace_events.c               |   4 +-
 kernel/trace/trace_events_hist.c          |   6 +-
 lib/seq_buf.c                             |  37 +-
 lib/tests/seq_buf_kunit.c                 | 537 +++++++++++++++++++++-
 tools/testing/nvdimm/test/ndtest.c        |   2 +-
 11 files changed, 746 insertions(+), 54 deletions(-)

-- 
2.55.0