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Commit a7c6f571 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner
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seqcount: Rename write_seqcount_barrier() 



I'll shortly be introducing another seqcount primitive that's useful
to provide ordering semantics and would like to use the
write_seqcount_barrier() name for that.

Seeing how there's only one user of the current primitive, lets rename
it to invalidate, as that appears what its doing.

While there, employ lockdep_assert_held() instead of
assert_spin_locked() to not generate debug code for regular kernels.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: wanpeng.li@linux.intel.com
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.279926217@infradead.org


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 8edfb036

fs/dcache.c

+8 −8
Original line number Diff line number Diff line
@@ -322,17 +322,17 @@ static void dentry_free(struct dentry *dentry) 
}



/**

 * dentry_rcuwalk_barrier - invalidate in-progress rcu-walk lookups

 * dentry_rcuwalk_invalidate - invalidate in-progress rcu-walk lookups

 * @dentry: the target dentry

 * After this call, in-progress rcu-walk path lookup will fail. This

 * should be called after unhashing, and after changing d_inode (if

 * the dentry has not already been unhashed).

 */

static inline void dentry_rcuwalk_barrier(struct dentry *dentry)

static inline void dentry_rcuwalk_invalidate(struct dentry *dentry)

{

	assert_spin_locked(&dentry->d_lock);

	/* Go through a barrier */

	write_seqcount_barrier(&dentry->d_seq);

	lockdep_assert_held(&dentry->d_lock);

	/* Go through am invalidation barrier */

	write_seqcount_invalidate(&dentry->d_seq);

}



/*
@@ -372,7 +372,7 @@ static void dentry_unlink_inode(struct dentry * dentry) 
	struct inode *inode = dentry->d_inode;

	__d_clear_type_and_inode(dentry);

	hlist_del_init(&dentry->d_u.d_alias);

	dentry_rcuwalk_barrier(dentry);

	dentry_rcuwalk_invalidate(dentry);

	spin_unlock(&dentry->d_lock);

	spin_unlock(&inode->i_lock);

	if (!inode->i_nlink)
@@ -494,7 +494,7 @@ void __d_drop(struct dentry *dentry) 
		__hlist_bl_del(&dentry->d_hash);

		dentry->d_hash.pprev = NULL;

		hlist_bl_unlock(b);

		dentry_rcuwalk_barrier(dentry);

		dentry_rcuwalk_invalidate(dentry);

	}

}

EXPORT_SYMBOL(__d_drop);
@@ -1752,7 +1752,7 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode) 
	if (inode)

		hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);

	__d_set_inode_and_type(dentry, inode, add_flags);

	dentry_rcuwalk_barrier(dentry);

	dentry_rcuwalk_invalidate(dentry);

	spin_unlock(&dentry->d_lock);

	fsnotify_d_instantiate(dentry, inode);

}

include/linux/seqlock.h

+3 −3
Original line number Diff line number Diff line
@@ -266,13 +266,13 @@ static inline void write_seqcount_end(seqcount_t *s) 
}



/**

 * write_seqcount_barrier - invalidate in-progress read-side seq operations

 * write_seqcount_invalidate - invalidate in-progress read-side seq operations

 * @s: pointer to seqcount_t

 *

 * After write_seqcount_barrier, no read-side seq operations will complete

 * After write_seqcount_invalidate, no read-side seq operations will complete

 * successfully and see data older than this.

 */

static inline void write_seqcount_barrier(seqcount_t *s)

static inline void write_seqcount_invalidate(seqcount_t *s)

{

	smp_wmb();

	s->sequence+=2;