Commit 6e649d08 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'locking-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull locking updates from Ingo Molnar:

 - rwsem micro-optimizations

 - spinlock micro-optimizations

 - cleanups, simplifications

* tag 'locking-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  vduse: Remove include of rwlock.h
  locking/lockdep: Remove lockdep_init_map_crosslock.
  x86/ACPI/boot: Use try_cmpxchg() in __acpi_{acquire,release}_global_lock()
  x86/PAT: Use try_cmpxchg() in set_page_memtype()
  locking/rwsem: Disable preemption in all down_write*() and up_write() code paths
  locking/rwsem: Disable preemption in all down_read*() and up_read() code paths
  locking/rwsem: Prevent non-first waiter from spinning in down_write() slowpath
  locking/qspinlock: Micro-optimize pending state waiting for unlock
parents db77b850 3b4863fa

arch/x86/kernel/acpi/boot.c

+8 −8
Original line number Diff line number Diff line
@@ -1840,23 +1840,23 @@ early_param("acpi_sci", setup_acpi_sci); 


int __acpi_acquire_global_lock(unsigned int *lock)

{

	unsigned int old, new, val;

	unsigned int old, new;



	old = READ_ONCE(*lock);

	do {

		old = *lock;

		new = (((old & ~0x3) + 2) + ((old >> 1) & 0x1));

		val = cmpxchg(lock, old, new);

	} while (unlikely (val != old));

	} while (!try_cmpxchg(lock, &old, new));

	return ((new & 0x3) < 3) ? -1 : 0;

}



int __acpi_release_global_lock(unsigned int *lock)

{

	unsigned int old, new, val;

	unsigned int old, new;



	old = READ_ONCE(*lock);

	do {

		old = *lock;

		new = old & ~0x3;

		val = cmpxchg(lock, old, new);

	} while (unlikely (val != old));

	} while (!try_cmpxchg(lock, &old, new));

	return old & 0x1;

}

arch/x86/mm/pat/memtype.c

+2 −2
Original line number Diff line number Diff line
@@ -159,10 +159,10 @@ static inline void set_page_memtype(struct page *pg, 
		break;

	}



	old_flags = READ_ONCE(pg->flags);

	do {

		old_flags = pg->flags;

		new_flags = (old_flags & _PGMT_CLEAR_MASK) | memtype_flags;

	} while (cmpxchg(&pg->flags, old_flags, new_flags) != old_flags);

	} while (!try_cmpxchg(&pg->flags, &old_flags, new_flags));

}

#else

static inline enum page_cache_mode get_page_memtype(struct page *pg)

drivers/vdpa/vdpa_user/iova_domain.h

+0 −1
Original line number Diff line number Diff line
@@ -14,7 +14,6 @@ 
#include <linux/iova.h>

#include <linux/dma-mapping.h>

#include <linux/vhost_iotlb.h>

#include <linux/rwlock.h>



#define IOVA_START_PFN 1

include/linux/lockdep.h

+0 −1
Original line number Diff line number Diff line
@@ -435,7 +435,6 @@ enum xhlock_context_t { 
	XHLOCK_CTX_NR,

};



#define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)

/*

 * To initialize a lockdep_map statically use this macro.

 * Note that _name must not be NULL.

kernel/locking/qspinlock.c

+2 −2
Original line number Diff line number Diff line
@@ -371,7 +371,7 @@ void __lockfunc queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) 
	/*

	 * We're pending, wait for the owner to go away.

	 *

	 * 0,1,1 -> 0,1,0

	 * 0,1,1 -> *,1,0

	 *

	 * this wait loop must be a load-acquire such that we match the

	 * store-release that clears the locked bit and create lock
@@ -380,7 +380,7 @@ void __lockfunc queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) 
	 * barriers.

	 */

	if (val & _Q_LOCKED_MASK)

		atomic_cond_read_acquire(&lock->val, !(VAL & _Q_LOCKED_MASK));

		smp_cond_load_acquire(&lock->locked, !VAL);



	/*

	 * take ownership and clear the pending bit.