[PATCH RT 1/9] mm, zsmalloc: Convert zsmalloc_handle.lock to spinlock_t

Steven Rostedt
2021-11-16T00:13:55Z

From: Mike Galbraith <efault@gmx.de>

local_lock_t becoming a synonym of spinlock_t had consequences for the RT
mods to zsmalloc, which were taking a mutex while holding a local_lock,
inspiring a lockdep "BUG: Invalid wait context" gripe.

Converting zsmalloc_handle.lock to a spinlock_t restored lockdep silence.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
mm/zsmalloc.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 277d426c881f..3595c1644135 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -82,7 +82,7 @@

struct zsmalloc_handle {
unsigned long addr;
- struct mutex lock;
+ spinlock_t lock;
};

#define ZS_HANDLE_ALLOC_SIZE (sizeof(struct zsmalloc_handle))
@@ -370,7 +370,7 @@ static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
if (p) {
struct zsmalloc_handle *zh = p;

- mutex_init(&zh->lock);
+ spin_lock_init(&zh->lock);
}
#endif
return (unsigned long)p;
@@ -930,7 +930,7 @@ static inline int testpin_tag(unsigned long handle)
#ifdef CONFIG_PREEMPT_RT
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);

- return mutex_is_locked(&zh->lock);
+ return spin_is_locked(&zh->lock);
#else
return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle);
#endif
@@ -941,7 +941,7 @@ static inline int trypin_tag(unsigned long handle)
#ifdef CONFIG_PREEMPT_RT
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);

- return mutex_trylock(&zh->lock);
+ return spin_trylock(&zh->lock);
#else
return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle);
#endif
@@ -952,7 +952,7 @@ static void pin_tag(unsigned long handle) __acquires(bitlock)
#ifdef CONFIG_PREEMPT_RT
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);

- return mutex_lock(&zh->lock);
+ return spin_lock(&zh->lock);
#else
bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle);
#endif
@@ -963,7 +963,7 @@ static void unpin_tag(unsigned long handle) __releases(bitlock)
#ifdef CONFIG_PREEMPT_RT
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);

- return mutex_unlock(&zh->lock);
+ return spin_unlock(&zh->lock);
#else
bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle);
#endif
--
2.33.0