Commit 73f5c66d authored by Gao Xiang's avatar Gao Xiang Committed by Greg Kroah-Hartman
Browse files

staging: erofs: fix `erofs_workgroup_{try_to_freeze, unfreeze}' 



There are two minor issues in the current freeze interface:

   1) Freeze interfaces have not related with CONFIG_DEBUG_SPINLOCK,
      therefore fix the incorrect conditions;

   2) For SMP platforms, it should also disable preemption before
      doing atomic_cmpxchg in case that some high priority tasks
      preempt between atomic_cmpxchg and disable_preempt, then spin
      on the locked refcount later.

Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarGao Xiang <gaoxiang25@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent df134b8d

drivers/staging/erofs/internal.h

+25 −16
Original line number Diff line number Diff line
@@ -194,40 +194,49 @@ struct erofs_workgroup { 


#define EROFS_LOCKED_MAGIC     (INT_MIN | 0xE0F510CCL)



static inline bool erofs_workgroup_try_to_freeze(

	struct erofs_workgroup *grp, int v)

#if defined(CONFIG_SMP)

static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,

						 int val)

{

#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)

	if (v != atomic_cmpxchg(&grp->refcount,

		v, EROFS_LOCKED_MAGIC))

		return false;

	preempt_disable();

#else

	preempt_disable();

	if (atomic_read(&grp->refcount) != v) {

	if (val != atomic_cmpxchg(&grp->refcount, val, EROFS_LOCKED_MAGIC)) {

		preempt_enable();

		return false;

	}

#endif

	return true;

}



static inline void erofs_workgroup_unfreeze(

	struct erofs_workgroup *grp, int v)

static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,

					    int orig_val)

{

#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)

	atomic_set(&grp->refcount, v);

#endif

	atomic_set(&grp->refcount, orig_val);

	preempt_enable();

}



#if defined(CONFIG_SMP)

static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)

{

	return atomic_cond_read_relaxed(&grp->refcount,

					VAL != EROFS_LOCKED_MAGIC);

}

#else

static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,

						 int val)

{

	preempt_disable();

	/* no need to spin on UP platforms, let's just disable preemption. */

	if (val != atomic_read(&grp->refcount)) {

		preempt_enable();

		return false;

	}

	return true;

}



static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,

					    int orig_val)

{

	preempt_enable();

}



static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)

{

	int v = atomic_read(&grp->refcount);

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