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locking/lockdep: Move hlock_equal() to the respective #ifdeffery

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When hlock_equal() is unused, it prevents kernel builds with clang,
`make W=1` and CONFIG_WERROR=y, CONFIG_LOCKDEP=y and
CONFIG_LOCKDEP_SMALL=n:

  lockdep.c:2005:20: error: unused function 'hlock_equal' [-Werror,-Wunused-function]

Fix this by moving the function to the respective existing ifdeffery
for its the only user.

See also:

  6863f5643d ("kbuild: allow Clang to find unused static inline functions for W=1 build")

Fixes: 68e3056785 ("lockdep: Adjust check_redundant() for recursive read change")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20250506042049.50060-2-boqun.feng@gmail.com
This commit is contained in:
Andy Shevchenko
2025-05-06 18:34:31 +02:00
committed by Ingo Molnar
parent 92a09c4746
commit 96ca1830e1
1 changed files with 35 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/locking/lockdep.c
+35 -35
View File
@@ -1976,41 +1976,6 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth,
print_circular_bug_entry(entry, depth);
}
/*
* We are about to add A -> B into the dependency graph, and in __bfs() a
* strong dependency path A -> .. -> B is found: hlock_class equals
* entry->class.
*
* If A -> .. -> B can replace A -> B in any __bfs() search (means the former
* is _stronger_ than or equal to the latter), we consider A -> B as redundant.
* For example if A -> .. -> B is -(EN)-> (i.e. A -(E*)-> .. -(*N)-> B), and A
* -> B is -(ER)-> or -(EN)->, then we don't need to add A -> B into the
* dependency graph, as any strong path ..-> A -> B ->.. we can get with
* having dependency A -> B, we could already get a equivalent path ..-> A ->
* .. -> B -> .. with A -> .. -> B. Therefore A -> B is redundant.
*
* We need to make sure both the start and the end of A -> .. -> B is not
* weaker than A -> B. For the start part, please see the comment in
* check_redundant(). For the end part, we need:
*
* Either
*
* a) A -> B is -(*R)-> (everything is not weaker than that)
*
* or
*
* b) A -> .. -> B is -(*N)-> (nothing is stronger than this)
*
*/
static inline bool hlock_equal(struct lock_list *entry, void *data)
{
struct held_lock *hlock = (struct held_lock *)data;
return hlock_class(hlock) == entry->class && /* Found A -> .. -> B */
(hlock->read == 2 || /* A -> B is -(*R)-> */
!entry->only_xr); /* A -> .. -> B is -(*N)-> */
}
/*
* We are about to add B -> A into the dependency graph, and in __bfs() a
* strong dependency path A -> .. -> B is found: hlock_class equals
@@ -2915,6 +2880,41 @@ static inline bool usage_skip(struct lock_list *entry, void *mask)
#endif /* CONFIG_TRACE_IRQFLAGS */
#ifdef CONFIG_LOCKDEP_SMALL
/*
* We are about to add A -> B into the dependency graph, and in __bfs() a
* strong dependency path A -> .. -> B is found: hlock_class equals
* entry->class.
*
* If A -> .. -> B can replace A -> B in any __bfs() search (means the former
* is _stronger_ than or equal to the latter), we consider A -> B as redundant.
* For example if A -> .. -> B is -(EN)-> (i.e. A -(E*)-> .. -(*N)-> B), and A
* -> B is -(ER)-> or -(EN)->, then we don't need to add A -> B into the
* dependency graph, as any strong path ..-> A -> B ->.. we can get with
* having dependency A -> B, we could already get a equivalent path ..-> A ->
* .. -> B -> .. with A -> .. -> B. Therefore A -> B is redundant.
*
* We need to make sure both the start and the end of A -> .. -> B is not
* weaker than A -> B. For the start part, please see the comment in
* check_redundant(). For the end part, we need:
*
* Either
*
* a) A -> B is -(*R)-> (everything is not weaker than that)
*
* or
*
* b) A -> .. -> B is -(*N)-> (nothing is stronger than this)
*
*/
static inline bool hlock_equal(struct lock_list *entry, void *data)
{
struct held_lock *hlock = (struct held_lock *)data;
return hlock_class(hlock) == entry->class && /* Found A -> .. -> B */
(hlock->read == 2 || /* A -> B is -(*R)-> */
!entry->only_xr); /* A -> .. -> B is -(*N)-> */
}
/*
* Check that the dependency graph starting at <src> can lead to
* <target> or not. If it can, <src> -> <target> dependency is already