Add support for Clang's context analysis for ww_mutex.
The programming model for ww_mutex is subtly more complex than other
locking primitives when using ww_acquire_ctx. Encoding the respective
pre-conditions for ww_mutex lock/unlock based on ww_acquire_ctx state
using Clang's context analysis makes incorrect use of the API harder.
Signed-off-by: Marco Elver <elver@google.com>
---
v5:
* Rename "context guard" -> "context lock".
v4:
* Rename capability -> context analysis.
v3:
* __assert -> __assume rename
v2:
* New patch.
---
Documentation/dev-tools/context-analysis.rst | 3 +-
include/linux/ww_mutex.h | 22 +++++--
lib/test_context-analysis.c | 69 ++++++++++++++++++++
3 files changed, 87 insertions(+), 7 deletions(-)
diff --git a/Documentation/dev-tools/context-analysis.rst b/Documentation/dev-tools/context-analysis.rst
index a48b75f45e79..8dd6c0d695aa 100644
--- a/Documentation/dev-tools/context-analysis.rst
+++ b/Documentation/dev-tools/context-analysis.rst
@@ -80,7 +80,8 @@ Supported Kernel Primitives
Currently the following synchronization primitives are supported:
`raw_spinlock_t`, `spinlock_t`, `rwlock_t`, `mutex`, `seqlock_t`,
-`bit_spinlock`, RCU, SRCU (`srcu_struct`), `rw_semaphore`, `local_lock_t`.
+`bit_spinlock`, RCU, SRCU (`srcu_struct`), `rw_semaphore`, `local_lock_t`,
+`ww_mutex`.
For context locks with an initialization function (e.g., `spin_lock_init()`),
calling this function before initializing any guarded members or globals
diff --git a/include/linux/ww_mutex.h b/include/linux/ww_mutex.h
index 45ff6f7a872b..58e959ee10e9 100644
--- a/include/linux/ww_mutex.h
+++ b/include/linux/ww_mutex.h
@@ -44,7 +44,7 @@ struct ww_class {
unsigned int is_wait_die;
};
-struct ww_mutex {
+context_lock_struct(ww_mutex) {
struct WW_MUTEX_BASE base;
struct ww_acquire_ctx *ctx;
#ifdef DEBUG_WW_MUTEXES
@@ -52,7 +52,7 @@ struct ww_mutex {
#endif
};
-struct ww_acquire_ctx {
+context_lock_struct(ww_acquire_ctx) {
struct task_struct *task;
unsigned long stamp;
unsigned int acquired;
@@ -107,6 +107,7 @@ struct ww_acquire_ctx {
*/
static inline void ww_mutex_init(struct ww_mutex *lock,
struct ww_class *ww_class)
+ __assumes_ctx_lock(lock)
{
ww_mutex_base_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);
lock->ctx = NULL;
@@ -141,6 +142,7 @@ static inline void ww_mutex_init(struct ww_mutex *lock,
*/
static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
struct ww_class *ww_class)
+ __acquires(ctx) __no_context_analysis
{
ctx->task = current;
ctx->stamp = atomic_long_inc_return_relaxed(&ww_class->stamp);
@@ -179,6 +181,7 @@ static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
* data structures.
*/
static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
+ __releases(ctx) __acquires_shared(ctx) __no_context_analysis
{
#ifdef DEBUG_WW_MUTEXES
lockdep_assert_held(ctx);
@@ -196,6 +199,7 @@ static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
* mutexes have been released with ww_mutex_unlock.
*/
static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
+ __releases_shared(ctx) __no_context_analysis
{
#ifdef CONFIG_DEBUG_LOCK_ALLOC
mutex_release(&ctx->first_lock_dep_map, _THIS_IP_);
@@ -245,7 +249,8 @@ static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
*
* A mutex acquired with this function must be released with ww_mutex_unlock.
*/
-extern int /* __must_check */ ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx);
+extern int /* __must_check */ ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+ __cond_acquires(0, lock) __must_hold(ctx);
/**
* ww_mutex_lock_interruptible - acquire the w/w mutex, interruptible
@@ -278,7 +283,8 @@ extern int /* __must_check */ ww_mutex_lock(struct ww_mutex *lock, struct ww_acq
* A mutex acquired with this function must be released with ww_mutex_unlock.
*/
extern int __must_check ww_mutex_lock_interruptible(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx);
+ struct ww_acquire_ctx *ctx)
+ __cond_acquires(0, lock) __must_hold(ctx);
/**
* ww_mutex_lock_slow - slowpath acquiring of the w/w mutex
@@ -305,6 +311,7 @@ extern int __must_check ww_mutex_lock_interruptible(struct ww_mutex *lock,
*/
static inline void
ww_mutex_lock_slow(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+ __acquires(lock) __must_hold(ctx) __no_context_analysis
{
int ret;
#ifdef DEBUG_WW_MUTEXES
@@ -342,6 +349,7 @@ ww_mutex_lock_slow(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
static inline int __must_check
ww_mutex_lock_slow_interruptible(struct ww_mutex *lock,
struct ww_acquire_ctx *ctx)
+ __cond_acquires(0, lock) __must_hold(ctx)
{
#ifdef DEBUG_WW_MUTEXES
DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);
@@ -349,10 +357,11 @@ ww_mutex_lock_slow_interruptible(struct ww_mutex *lock,
return ww_mutex_lock_interruptible(lock, ctx);
}
-extern void ww_mutex_unlock(struct ww_mutex *lock);
+extern void ww_mutex_unlock(struct ww_mutex *lock) __releases(lock);
extern int __must_check ww_mutex_trylock(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx);
+ struct ww_acquire_ctx *ctx)
+ __cond_acquires(true, lock) __must_hold(ctx);
/***
* ww_mutex_destroy - mark a w/w mutex unusable
@@ -363,6 +372,7 @@ extern int __must_check ww_mutex_trylock(struct ww_mutex *lock,
* this function is called.
*/
static inline void ww_mutex_destroy(struct ww_mutex *lock)
+ __must_not_hold(lock)
{
#ifndef CONFIG_PREEMPT_RT
mutex_destroy(&lock->base);
diff --git a/lib/test_context-analysis.c b/lib/test_context-analysis.c
index 003e64cac540..2dc404456497 100644
--- a/lib/test_context-analysis.c
+++ b/lib/test_context-analysis.c
@@ -14,6 +14,7 @@
#include <linux/seqlock.h>
#include <linux/spinlock.h>
#include <linux/srcu.h>
+#include <linux/ww_mutex.h>
/*
* Test that helper macros work as expected.
@@ -531,3 +532,71 @@ static void __used test_local_trylock(void)
local_unlock(&test_local_trylock_data.lock);
}
}
+
+static DEFINE_WD_CLASS(ww_class);
+
+struct test_ww_mutex_data {
+ struct ww_mutex mtx;
+ int counter __guarded_by(&mtx);
+};
+
+static void __used test_ww_mutex_init(struct test_ww_mutex_data *d)
+{
+ ww_mutex_init(&d->mtx, &ww_class);
+ d->counter = 0;
+}
+
+static void __used test_ww_mutex_lock_noctx(struct test_ww_mutex_data *d)
+{
+ if (!ww_mutex_lock(&d->mtx, NULL)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ if (!ww_mutex_lock_interruptible(&d->mtx, NULL)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ if (ww_mutex_trylock(&d->mtx, NULL)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ ww_mutex_lock_slow(&d->mtx, NULL);
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+
+ ww_mutex_destroy(&d->mtx);
+}
+
+static void __used test_ww_mutex_lock_ctx(struct test_ww_mutex_data *d)
+{
+ struct ww_acquire_ctx ctx;
+
+ ww_acquire_init(&ctx, &ww_class);
+
+ if (!ww_mutex_lock(&d->mtx, &ctx)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ if (!ww_mutex_lock_interruptible(&d->mtx, &ctx)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ if (ww_mutex_trylock(&d->mtx, &ctx)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ ww_mutex_lock_slow(&d->mtx, &ctx);
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+
+ ww_acquire_done(&ctx);
+ ww_acquire_fini(&ctx);
+
+ ww_mutex_destroy(&d->mtx);
+}
--
2.52.0.322.g1dd061c0dc-googOn 12/19/25 8:40 AM, Marco Elver wrote:
> Add support for Clang's context analysis for ww_mutex.
>
> The programming model for ww_mutex is subtly more complex than other
> locking primitives when using ww_acquire_ctx. Encoding the respective
> pre-conditions for ww_mutex lock/unlock based on ww_acquire_ctx state
> using Clang's context analysis makes incorrect use of the API harder.
That's a very short description. It should have been explained in the
patch description how the ww_acquire_ctx changes affect callers of the
ww_acquire_{init,done,fini}() functions.
> static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
> struct ww_class *ww_class)
> + __acquires(ctx) __no_context_analysis
> [ ... ]
> static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
> + __releases(ctx) __acquires_shared(ctx) __no_context_analysis
> {
> [ ... ]
> static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
> + __releases_shared(ctx) __no_context_analysis
The above changes make it mandatory to call ww_acquire_done() before
calling ww_acquire_fini(). In Documentation/locking/ww-mutex-design.rst
there is an example where there is no ww_acquire_done() call between
ww_acquire_init() and ww_acquire_fini() (see also line 202). The
function dma_resv_lockdep() in drivers/dma-buf/dma-resv.c doesn't call
ww_acquire_done() at all. Does this mean that the above annotations are
wrong? Is there a better solution than removing the __acquire() and
__release() annotations from the above three functions?
Bart.
On Fri, Jan 09, 2026 at 12:16PM -0800, Bart Van Assche wrote:
> On 12/19/25 8:40 AM, Marco Elver wrote:
> > Add support for Clang's context analysis for ww_mutex.
> >
> > The programming model for ww_mutex is subtly more complex than other
> > locking primitives when using ww_acquire_ctx. Encoding the respective
> > pre-conditions for ww_mutex lock/unlock based on ww_acquire_ctx state
> > using Clang's context analysis makes incorrect use of the API harder.
>
> That's a very short description. It should have been explained in the
> patch description how the ww_acquire_ctx changes affect callers of the
> ww_acquire_{init,done,fini}() functions.
How so? The API is the same (now statically enforced), and there's no
functional change at runtime. Or did I miss something?
> > static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
> > struct ww_class *ww_class)
> > + __acquires(ctx) __no_context_analysis
> > [ ... ]
> > static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
> > + __releases(ctx) __acquires_shared(ctx) __no_context_analysis
> > {
> > [ ... ]
> > static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
> > + __releases_shared(ctx) __no_context_analysis
>
> The above changes make it mandatory to call ww_acquire_done() before
> calling ww_acquire_fini(). In Documentation/locking/ww-mutex-design.rst
> there is an example where there is no ww_acquire_done() call between
> ww_acquire_init() and ww_acquire_fini() (see also line 202).
It might be worth updating the example with what the kernel-doc
documentation recommends (below).
> The
> function dma_resv_lockdep() in drivers/dma-buf/dma-resv.c doesn't call
> ww_acquire_done() at all. Does this mean that the above annotations are
> wrong?
If there's 1 out of N ww_mutex users that missed ww_acquire_done()
there's a good chance that 1 case is wrong.
But generally, depends if we want to enforce ww_acquire_done() or not
which itself is no-op in non-lockdep builds, however, with
DEBUG_WW_MUTEXES it's no longer no-op so it might be a good idea to
enforce it to get proper lockdep checking.
> Is there a better solution than removing the __acquire() and
> __release() annotations from the above three functions?
The kernel-doc comment for ww_acquire_done() says:
/**
* ww_acquire_done - marks the end of the acquire phase
* @ctx: the acquire context
*
>> * Marks the end of the acquire phase, any further w/w mutex lock calls using
>> * this context are forbidden.
>> *
>> * Calling this function is optional, it is just useful to document w/w mutex
>> * code and clearly designated the acquire phase from actually using the locked
>> * data structures.
*/
static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
__releases(ctx) __acquires_shared(ctx) __no_context_analysis
{
#ifdef DEBUG_WW_MUTEXES
lockdep_assert_held(ctx);
DEBUG_LOCKS_WARN_ON(ctx->done_acquire);
ctx->done_acquire = 1;
#endif
}
It states it's optional, but it's unclear if that's true with
DEBUG_WW_MUTEXES builds. I'd vote for enforcing use of
ww_acquire_done(). If there's old code that's not using it, it should be
added there to get proper lockdep checking.
(+Maarten) On 1/9/26 2:06 PM, Marco Elver wrote: > If there's 1 out of N ww_mutex users that missed ww_acquire_done() > there's a good chance that 1 case is wrong. $ git grep -w ww_acquire_done '**c'|wc -l 11 $ git grep -w ww_acquire_fini '**c'|wc -l 33 The above statistics show that there are more cases where ww_acquire_done() is not called rather than cases where ww_acquire_done() is called. Maarten, since you introduced the ww_mutex code, do you perhaps prefer that calling ww_acquire_done() is optional or rather that all users that do not call ww_acquire_done() are modified such that they call ww_acquire_done()? The full email conversation is available here: https://lore.kernel.org/all/20251219154418.3592607-1-elver@google.com/ Thanks, Bart.
Hey, The acquire_done() call was always optional. It's meant to indicate that after this point, ww_acquire_lock may no longer be called and backoff can no longer occur. It's allowed to call ww_acquire_fini() without ww_acquire_done() Think of this case: ww_acquire_init() ww_acquire_lock_interruptible() -> -ERESTARTSYS ww_acquire_fini() Here it wouldn't make sense to call ww_acquire_done(). It's mostly to facilitate this case: ww_acquire_init() ww_acquire_lock() a bunch. /* Got all locks, do the work as no more backoff occurs */ ww_acquire_done() ... unlock_all() ww_acquire_fini() If you call ww_acquire_lock after done, a warning should occur as this should no longer happen. Kind regards, ~Maarten Lankhorst Den 2026-01-09 kl. 22:26, skrev Bart Van Assche: > (+Maarten) > > On 1/9/26 2:06 PM, Marco Elver wrote: >> If there's 1 out of N ww_mutex users that missed ww_acquire_done() >> there's a good chance that 1 case is wrong. > > $ git grep -w ww_acquire_done '**c'|wc -l > 11 > $ git grep -w ww_acquire_fini '**c'|wc -l > 33 > > The above statistics show that there are more cases where > ww_acquire_done() is not called rather than cases where > ww_acquire_done() is called. > > Maarten, since you introduced the ww_mutex code, do you perhaps prefer > that calling ww_acquire_done() is optional or rather that all users that > do not call ww_acquire_done() are modified such that they call > ww_acquire_done()? The full email conversation is available here: > https://lore.kernel.org/all/20251219154418.3592607-1-elver@google.com/ > > Thanks, > > Bart.
The following commit has been merged into the locking/core branch of tip:
Commit-ID: 47907461e4f6fcdce8cf91dd164369192deeb7c4
Gitweb: https://git.kernel.org/tip/47907461e4f6fcdce8cf91dd164369192deeb7c4
Author: Marco Elver <elver@google.com>
AuthorDate: Fri, 19 Dec 2025 16:40:09 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 05 Jan 2026 16:43:32 +01:00
locking/ww_mutex: Support Clang's context analysis
Add support for Clang's context analysis for ww_mutex.
The programming model for ww_mutex is subtly more complex than other
locking primitives when using ww_acquire_ctx. Encoding the respective
pre-conditions for ww_mutex lock/unlock based on ww_acquire_ctx state
using Clang's context analysis makes incorrect use of the API harder.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-21-elver@google.com
---
Documentation/dev-tools/context-analysis.rst | 3 +-
include/linux/ww_mutex.h | 22 ++++--
lib/test_context-analysis.c | 69 +++++++++++++++++++-
3 files changed, 87 insertions(+), 7 deletions(-)
diff --git a/Documentation/dev-tools/context-analysis.rst b/Documentation/dev-tools/context-analysis.rst
index a48b75f..8dd6c0d 100644
--- a/Documentation/dev-tools/context-analysis.rst
+++ b/Documentation/dev-tools/context-analysis.rst
@@ -80,7 +80,8 @@ Supported Kernel Primitives
Currently the following synchronization primitives are supported:
`raw_spinlock_t`, `spinlock_t`, `rwlock_t`, `mutex`, `seqlock_t`,
-`bit_spinlock`, RCU, SRCU (`srcu_struct`), `rw_semaphore`, `local_lock_t`.
+`bit_spinlock`, RCU, SRCU (`srcu_struct`), `rw_semaphore`, `local_lock_t`,
+`ww_mutex`.
For context locks with an initialization function (e.g., `spin_lock_init()`),
calling this function before initializing any guarded members or globals
diff --git a/include/linux/ww_mutex.h b/include/linux/ww_mutex.h
index 45ff6f7..58e959e 100644
--- a/include/linux/ww_mutex.h
+++ b/include/linux/ww_mutex.h
@@ -44,7 +44,7 @@ struct ww_class {
unsigned int is_wait_die;
};
-struct ww_mutex {
+context_lock_struct(ww_mutex) {
struct WW_MUTEX_BASE base;
struct ww_acquire_ctx *ctx;
#ifdef DEBUG_WW_MUTEXES
@@ -52,7 +52,7 @@ struct ww_mutex {
#endif
};
-struct ww_acquire_ctx {
+context_lock_struct(ww_acquire_ctx) {
struct task_struct *task;
unsigned long stamp;
unsigned int acquired;
@@ -107,6 +107,7 @@ struct ww_acquire_ctx {
*/
static inline void ww_mutex_init(struct ww_mutex *lock,
struct ww_class *ww_class)
+ __assumes_ctx_lock(lock)
{
ww_mutex_base_init(&lock->base, ww_class->mutex_name, &ww_class->mutex_key);
lock->ctx = NULL;
@@ -141,6 +142,7 @@ static inline void ww_mutex_init(struct ww_mutex *lock,
*/
static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
struct ww_class *ww_class)
+ __acquires(ctx) __no_context_analysis
{
ctx->task = current;
ctx->stamp = atomic_long_inc_return_relaxed(&ww_class->stamp);
@@ -179,6 +181,7 @@ static inline void ww_acquire_init(struct ww_acquire_ctx *ctx,
* data structures.
*/
static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
+ __releases(ctx) __acquires_shared(ctx) __no_context_analysis
{
#ifdef DEBUG_WW_MUTEXES
lockdep_assert_held(ctx);
@@ -196,6 +199,7 @@ static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
* mutexes have been released with ww_mutex_unlock.
*/
static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
+ __releases_shared(ctx) __no_context_analysis
{
#ifdef CONFIG_DEBUG_LOCK_ALLOC
mutex_release(&ctx->first_lock_dep_map, _THIS_IP_);
@@ -245,7 +249,8 @@ static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
*
* A mutex acquired with this function must be released with ww_mutex_unlock.
*/
-extern int /* __must_check */ ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx);
+extern int /* __must_check */ ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+ __cond_acquires(0, lock) __must_hold(ctx);
/**
* ww_mutex_lock_interruptible - acquire the w/w mutex, interruptible
@@ -278,7 +283,8 @@ extern int /* __must_check */ ww_mutex_lock(struct ww_mutex *lock, struct ww_acq
* A mutex acquired with this function must be released with ww_mutex_unlock.
*/
extern int __must_check ww_mutex_lock_interruptible(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx);
+ struct ww_acquire_ctx *ctx)
+ __cond_acquires(0, lock) __must_hold(ctx);
/**
* ww_mutex_lock_slow - slowpath acquiring of the w/w mutex
@@ -305,6 +311,7 @@ extern int __must_check ww_mutex_lock_interruptible(struct ww_mutex *lock,
*/
static inline void
ww_mutex_lock_slow(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+ __acquires(lock) __must_hold(ctx) __no_context_analysis
{
int ret;
#ifdef DEBUG_WW_MUTEXES
@@ -342,6 +349,7 @@ ww_mutex_lock_slow(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
static inline int __must_check
ww_mutex_lock_slow_interruptible(struct ww_mutex *lock,
struct ww_acquire_ctx *ctx)
+ __cond_acquires(0, lock) __must_hold(ctx)
{
#ifdef DEBUG_WW_MUTEXES
DEBUG_LOCKS_WARN_ON(!ctx->contending_lock);
@@ -349,10 +357,11 @@ ww_mutex_lock_slow_interruptible(struct ww_mutex *lock,
return ww_mutex_lock_interruptible(lock, ctx);
}
-extern void ww_mutex_unlock(struct ww_mutex *lock);
+extern void ww_mutex_unlock(struct ww_mutex *lock) __releases(lock);
extern int __must_check ww_mutex_trylock(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx);
+ struct ww_acquire_ctx *ctx)
+ __cond_acquires(true, lock) __must_hold(ctx);
/***
* ww_mutex_destroy - mark a w/w mutex unusable
@@ -363,6 +372,7 @@ extern int __must_check ww_mutex_trylock(struct ww_mutex *lock,
* this function is called.
*/
static inline void ww_mutex_destroy(struct ww_mutex *lock)
+ __must_not_hold(lock)
{
#ifndef CONFIG_PREEMPT_RT
mutex_destroy(&lock->base);
diff --git a/lib/test_context-analysis.c b/lib/test_context-analysis.c
index 003e64c..2dc4044 100644
--- a/lib/test_context-analysis.c
+++ b/lib/test_context-analysis.c
@@ -14,6 +14,7 @@
#include <linux/seqlock.h>
#include <linux/spinlock.h>
#include <linux/srcu.h>
+#include <linux/ww_mutex.h>
/*
* Test that helper macros work as expected.
@@ -531,3 +532,71 @@ static void __used test_local_trylock(void)
local_unlock(&test_local_trylock_data.lock);
}
}
+
+static DEFINE_WD_CLASS(ww_class);
+
+struct test_ww_mutex_data {
+ struct ww_mutex mtx;
+ int counter __guarded_by(&mtx);
+};
+
+static void __used test_ww_mutex_init(struct test_ww_mutex_data *d)
+{
+ ww_mutex_init(&d->mtx, &ww_class);
+ d->counter = 0;
+}
+
+static void __used test_ww_mutex_lock_noctx(struct test_ww_mutex_data *d)
+{
+ if (!ww_mutex_lock(&d->mtx, NULL)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ if (!ww_mutex_lock_interruptible(&d->mtx, NULL)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ if (ww_mutex_trylock(&d->mtx, NULL)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ ww_mutex_lock_slow(&d->mtx, NULL);
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+
+ ww_mutex_destroy(&d->mtx);
+}
+
+static void __used test_ww_mutex_lock_ctx(struct test_ww_mutex_data *d)
+{
+ struct ww_acquire_ctx ctx;
+
+ ww_acquire_init(&ctx, &ww_class);
+
+ if (!ww_mutex_lock(&d->mtx, &ctx)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ if (!ww_mutex_lock_interruptible(&d->mtx, &ctx)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ if (ww_mutex_trylock(&d->mtx, &ctx)) {
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+ }
+
+ ww_mutex_lock_slow(&d->mtx, &ctx);
+ d->counter++;
+ ww_mutex_unlock(&d->mtx);
+
+ ww_acquire_done(&ctx);
+ ww_acquire_fini(&ctx);
+
+ ww_mutex_destroy(&d->mtx);
+}© 2016 - 2026 Red Hat, Inc.