Re: [PATCH v4 02/12] block/bdev: Annotate the blk_holder_ops callback functions

[Bart Van Assche <bvanassche@acm.org>]

On 5/13/26 6:36 AM, Nathan Chancellor wrote:
> While doing a dynamic check is more expensive than a version check, I
> would not worry much about that overhead if the check is worthwhile or
> valuable. In this case, I tend to agree with you that it would just be
> better to bump the minimum version of Clang required for context
> analysis because of the improvements (other than the function pointer
> support) that you have landed in main since release/22.x. While I am
> always sad to see support for older compilers dropped, I don't think
> clang-22 is widespread enough for that to really matter. On the other
> hand, I do worry that if we do not have a wide enough window of
> supported compilers for developers / maintainers to use, we won't be
> able to uncover potential problems to address in the compiler (I feel
> like getting __counted_by deployed was particular painful for this
> reason), if that makes sense.

It seems to me that increasing the required Clang version is the least
controversial approach. If nobody objects I will start testing the patch
below.

Thanks,

Bart.

Subject: [PATCH] lib/Kconfig.debug: Require Clang 23 for context analysis

Context annotations for function pointers will be supported by Clang 23
but are not supported by Clang 22. Bump the minimum required Clang
version in preparation of annotating the blk_holder_ops function pointer
members.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
  lib/Kconfig.debug | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 8ff5adcfe1e0..5b5d1d183618 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -630,7 +630,7 @@ config DEBUG_FORCE_WEAK_PER_CPU

  config WARN_CONTEXT_ANALYSIS
  	bool "Compiler context-analysis warnings"
-	depends on CC_IS_CLANG && CLANG_VERSION >= 220100
+	depends on CC_IS_CLANG && CLANG_VERSION >= 230000
  	# Branch profiling re-defines "if", which messes with the compiler's
  	# ability to analyze __cond_acquires(..), resulting in false positives.
  	depends on !TRACE_BRANCH_PROFILING
@@ -641,7 +641,7 @@ config WARN_CONTEXT_ANALYSIS
  	  and releasing user-definable "context locks".

  	  Clang's name of the feature is "Thread Safety Analysis". Requires
-	  Clang 22.1.0 or later.
+	  Clang 23.0 or later.

  	  Produces warnings by default. Select CONFIG_WERROR if you wish to
  	  turn these warnings into errors.