linux-kernel - [PATCH v3 0/8] cleanup: Introduce ACQUIRE(), a guard() for conditional locks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250711234932.671292-1-dan.j.williams@intel.com>
Date: Fri, 11 Jul 2025 16:49:24 -0700
From: Dan Williams <dan.j.williams@...el.com>
To: <linux-cxl@...r.kernel.org>
CC: <linux-kernel@...r.kernel.org>, Alison Schofield
	<alison.schofield@...el.com>, Dave Jiang <dave.jiang@...el.com>, "David
 Lechner" <dlechner@...libre.com>, Davidlohr Bueso <dave@...olabs.net>, "Fabio
 M. De Francesco" <fabio.m.de.francesco@...ux.intel.com>, Ingo Molnar
	<mingo@...nel.org>, Ira Weiny <ira.weiny@...el.com>, Jonathan Cameron
	<jonathan.cameron@...wei.com>, Linus Torvalds
	<torvalds@...ux-foundation.org>, "Peter Zijlstra (Intel)"
	<peterz@...radead.org>, Shiju Jose <shiju.jose@...wei.com>, Vishal Verma
	<vishal.l.verma@...el.com>
Subject: [PATCH v3 0/8] cleanup: Introduce ACQUIRE(), a guard() for conditional locks

Changes since v2 [1]:
- Pick up Acks and Reviews
- Whitespace fixups for cleanup.h changes (Jonathan)
- Use consistent local variable style for ACQUIRE_ERR() (Jonathan)
  - Not addressed: switch to less compact style ACQUIRE_ERR()
- Not addressed: pickup checkpatch change for ACQUIRE_ERR() style in
  this series (Alison)
- Drop the cxl_decoder_detach() CLASS() and convert to a helper function (Jonathan)
- Refactor attach_target() to make it easier to read (Jonathan)

[1]: http://lore.kernel.org/20250619050416.782871-1-dan.j.williams@intel.com

For those new to this set, the motivation for this work is that the CXL
subsystem adopted scope-based-cleanup helpers and achieved some decent
cleanups. However, that work stalled with conditional locks. It stalled
due to the pain points of scoped_cond_guard(). See patch1.

In the interim, approaches like rwsem_read_intr_acquire() attempted to
workaround the pain points, but started a "parallel universe" of helpers
that is not sustainable.

    0c6e6f1357cb cxl/edac: Add CXL memory device patrol scrub control feature

Peter fixed all of this up in a manner consistent with existing guards.
Take that proposal and run with it to unblock further cleanups of "goto"
in unwind paths in the CXL subsystem.

Potential follow-on work identified by this effort:

- __GUARD_IS_ERR() asm helper [2]
- Checkpatch fixups for proposed ACQUIRE_ERR() style [3]

[2]: http://lore.kernel.org/20250514064624.GA24938@noisy.programming.kicks-ass.net
[3]: http://lore.kernel.org/aGXDMZB6omShJpoj@aschofie-mobl2.lan

Dan Williams (7):
  cxl/mbox: Convert poison list mutex to ACQUIRE()
  cxl/decoder: Move decoder register programming to a helper
  cxl/decoder: Drop pointless locking
  cxl/region: Split commit_store() into __commit() and queue_reset()
    helpers
  cxl/region: Move ready-to-probe state check to a helper
  cxl/region: Consolidate cxl_decoder_kill_region() and
    cxl_region_detach()
  cxl: Convert to ACQUIRE() for conditional rwsem locking

Peter Zijlstra (1):
  cleanup: Introduce ACQUIRE() and ACQUIRE_ERR() for conditional locks

 drivers/cxl/core/cdat.c   |   6 +-
 drivers/cxl/core/core.h   |  32 ++-
 drivers/cxl/core/edac.c   |  44 ++--
 drivers/cxl/core/hdm.c    | 118 +++++-----
 drivers/cxl/core/mbox.c   |  13 +-
 drivers/cxl/core/memdev.c |  50 ++--
 drivers/cxl/core/port.c   |  27 +--
 drivers/cxl/core/region.c | 473 ++++++++++++++++++++------------------
 drivers/cxl/cxl.h         |  13 +-
 drivers/cxl/cxlmem.h      |   4 +-
 include/linux/cleanup.h   |  95 ++++++--
 include/linux/mutex.h     |   2 +-
 include/linux/rwsem.h     |   3 +-
 13 files changed, 480 insertions(+), 400 deletions(-)


base-commit: e04c78d86a9699d136910cfc0bdcf01087e3267e
-- 
2.50.0