[PATCH 0/5] scsi: lpfc: Remove all strlcat() uses

[Ian Bridges <icb@fastmail.org>]

In preparation for removing the strlcat() API[1], this series replaces
its 81 remaining call sites in the lpfc driver. The sites live in nine
string building functions across five files, and each patch converts
one source file.

Functions that accumulate a variable number of fragments move to
seq_buf. The three sysfs show functions move to sysfs_emit_at(), the
designated helper for sysfs output. lpfc_vport_symbolic_node_name()
builds five fixed fragments and becomes a single scnprintf() call.
The intermediate tmp buffers and the per fragment overflow checks
become unnecessary in every scheme. Each loop that appends keeps one
overflow exit, so a full buffer stops the iteration.

One cross-cutting behavior change applies to several patches. The old
code formatted each fragment into a fixed size tmp buffer before
appending it, so a fragment longer than that buffer was silently
truncated even when the destination had room for it. The replacements
format each fragment directly into the destination. Truncation is
still bounded by the destination size. The per patch changelogs call
out the affected functions.

The patch series was tested as follows. No hardware testing was
done. Testing on real adapters is welcome.

- W=1 builds of the whole driver directory, zero warnings.
- A userspace differential harness. The old and new function bodies
  are extracted verbatim from the two trees and compiled side by side
  against the real lib/seq_buf.c. 472000 randomized cases across all
  nine functions, including oversized inputs, undersized buffers and
  prefilled destinations, compared byte for byte under ASan and
  UBSan. All outputs are identical except two behavior changes.
  Those are the format string interpretation removed in patch 1 and
  the fragment cap removal in patch 2. The harness classifies every
  observed difference as exactly one of those two.
- A KUnit corpus. The nine functions run as compiled kernel code in a
  QEMU guest with KASAN, UBSAN and FORTIFY_SOURCE enabled, against
  fabricated adapter state covering both branches of every converted
  conditional that is compiled in. The LPFC_MXP_STAT debug block is
  disabled at compile time and was build tested with the macro
  defined. The same 40 test cases run on the unpatched base and
  on this series. The base run matches the old expected outputs, and
  the patched run is byte identical everywhere except the two
  documented changes.

[1] https://github.com/KSPP/linux/issues/370

Ian Bridges (5):
  scsi: lpfc: Replace strlcat() with seq_buf in lpfc_info()
  scsi: lpfc: Replace strlcat() with scnprintf() in
    lpfc_vport_symbolic_node_name()
  scsi: lpfc: Replace strlcat() with seq_buf in lpfc_rx_monitor_report()
  scsi: lpfc: Replace strlcat() with seq_buf in the debugfs dump helpers
  scsi: lpfc: Replace strlcat() with sysfs_emit_at() in the sysfs show
    functions

 drivers/scsi/lpfc/lpfc_attr.c    | 555 +++++++++++++------------------
 drivers/scsi/lpfc/lpfc_ct.c      |  29 +-
 drivers/scsi/lpfc/lpfc_debugfs.c | 202 +++++------
 drivers/scsi/lpfc/lpfc_scsi.c    |  49 +--
 drivers/scsi/lpfc/lpfc_scsi.h    |   3 -
 drivers/scsi/lpfc/lpfc_sli.c     |  43 +--
 6 files changed, 361 insertions(+), 520 deletions(-)

-- 
2.47.3