Documentation/kernel-hacking/locking.rst

400     static DEFINE_MUTEX(cache_lock);
405     /* Must be holding cache_lock */
418     /* Must be holding cache_lock */
427     /* Must be holding cache_lock */
452             mutex_lock(&cache_lock);
454             mutex_unlock(&cache_lock);
460             mutex_lock(&cache_lock);
462             mutex_unlock(&cache_lock);
470             mutex_lock(&cache_lock);
476             mutex_unlock(&cache_lock);
480 Note that we always make sure we have the cache_lock when we add,
509     -static DEFINE_MUTEX(cache_lock);
510     +static DEFINE_SPINLOCK(cache_lock);
526     -        mutex_lock(&cache_lock);
527     +        spin_lock_irqsave(&cache_lock, flags);
529     -        mutex_unlock(&cache_lock);
530     +        spin_unlock_irqrestore(&cache_lock, flags);
536     -        mutex_lock(&cache_lock);
539     +        spin_lock_irqsave(&cache_lock, flags);
541     -        mutex_unlock(&cache_lock);
542     +        spin_unlock_irqrestore(&cache_lock, flags);
551     -        mutex_lock(&cache_lock);
552     +        spin_lock_irqsave(&cache_lock, flags);
558     -        mutex_unlock(&cache_lock);
559     +        spin_unlock_irqrestore(&cache_lock, flags);
582 The first problem is that we use the ``cache_lock`` to protect objects:
631     +        spin_lock_irqsave(&cache_lock, flags);
633     +        spin_unlock_irqrestore(&cache_lock, flags);
640     +        spin_lock_irqsave(&cache_lock, flags);
642     +        spin_unlock_irqrestore(&cache_lock, flags);
645      /* Must be holding cache_lock */
662              spin_lock_irqsave(&cache_lock, flags);
665              spin_unlock_irqrestore(&cache_lock, flags);
675              spin_lock_irqsave(&cache_lock, flags);
683              spin_unlock_irqrestore(&cache_lock, flags);
743     -        spin_lock_irqsave(&cache_lock, flags);
745     -        spin_unlock_irqrestore(&cache_lock, flags);
754     -        spin_lock_irqsave(&cache_lock, flags);
756     -        spin_unlock_irqrestore(&cache_lock, flags);
760      /* Must be holding cache_lock */
777              spin_lock_irqsave(&cache_lock, flags);
780              spin_lock_irqsave(&cache_lock, flags);
785              spin_unlock_irqrestore(&cache_lock, flags);
796 -  You can make ``cache_lock`` non-static, and tell people to grab that
803 -  You can make the ``cache_lock`` protect only the cache itself, and
830     +        /* These two protected by cache_lock. */
844      static DEFINE_SPINLOCK(cache_lock);
851              spin_lock_irqsave(&cache_lock, flags);
855 ``cache_lock`` rather than the per-object lock: this is because it (like
1155     -        /* These two protected by cache_lock. */
1184      /* Must be holding cache_lock */
1195      /* Must be holding cache_lock */
1209     -        spin_lock_irqsave(&cache_lock, flags);
1214     -        spin_unlock_irqrestore(&cache_lock, flags);