Commit 20ec197b authored by David Howells's avatar David Howells
Browse files

fscache: Use refcount_t for the cookie refcount instead of atomic_t 



Use refcount_t for the fscache_cookie refcount instead of atomic_t and
rename the 'usage' member to 'ref' in such cases.  The tracepoints that
reference it change from showing "u=%d" to "r=%d".

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431204358.2908479.8006938388213098079.stgit@warthog.procyon.org.uk/
parent 33cba859

fs/fscache/cache.c

+1 −1
Original line number Diff line number Diff line
@@ -269,7 +269,7 @@ int fscache_add_cache(struct fscache_cache *cache, 
	hlist_add_head(&ifsdef->cookie_link,

		       &fscache_fsdef_index.backing_objects);



	atomic_inc(&fscache_fsdef_index.usage);

	refcount_inc(&fscache_fsdef_index.ref);



	/* done */

	spin_unlock(&fscache_fsdef_index.lock);

fs/fscache/cookie.c

+21 −10
Original line number Diff line number Diff line
@@ -164,7 +164,7 @@ struct fscache_cookie *fscache_alloc_cookie( 
			goto nomem;

	}



	atomic_set(&cookie->usage, 1);

	refcount_set(&cookie->ref, 1);

	atomic_set(&cookie->n_children, 0);

	cookie->debug_id = atomic_inc_return(&fscache_cookie_debug_id);
@@ -225,7 +225,7 @@ struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *candidate) 


collision:

	if (test_and_set_bit(FSCACHE_COOKIE_ACQUIRED, &cursor->flags)) {

		trace_fscache_cookie(cursor->debug_id, atomic_read(&cursor->usage),

		trace_fscache_cookie(cursor->debug_id, refcount_read(&cursor->ref),

				     fscache_cookie_collision);

		pr_err("Duplicate cookie detected\n");

		fscache_print_cookie(cursor, 'O');
@@ -826,13 +826,12 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, 
	BUG_ON(!radix_tree_empty(&cookie->stores));



	if (cookie->parent) {

		ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0);

		ASSERTCMP(refcount_read(&cookie->parent->ref), >, 0);

		ASSERTCMP(atomic_read(&cookie->parent->n_children), >, 0);

		atomic_dec(&cookie->parent->n_children);

	}



	/* Dispose of the netfs's link to the cookie */

	ASSERTCMP(atomic_read(&cookie->usage), >, 0);

	fscache_cookie_put(cookie, fscache_cookie_put_relinquish);



	_leave("");
@@ -862,18 +861,17 @@ void fscache_cookie_put(struct fscache_cookie *cookie, 
			enum fscache_cookie_trace where)

{

	struct fscache_cookie *parent;

	int usage;

	int ref;



	_enter("%x", cookie->debug_id);



	do {

		unsigned int cookie_debug_id = cookie->debug_id;

		usage = atomic_dec_return(&cookie->usage);

		trace_fscache_cookie(cookie_debug_id, usage, where);

		bool zero = __refcount_dec_and_test(&cookie->ref, &ref);



		if (usage > 0)

		trace_fscache_cookie(cookie_debug_id, ref - 1, where);

		if (!zero)

			return;

		BUG_ON(usage < 0);



		parent = cookie->parent;

		fscache_unhash_cookie(cookie);
@@ -886,6 +884,19 @@ void fscache_cookie_put(struct fscache_cookie *cookie, 
	_leave("");

}



/*

 * Get a reference to a cookie.

 */

struct fscache_cookie *fscache_cookie_get(struct fscache_cookie *cookie,

					  enum fscache_cookie_trace where)

{

	int ref;



	__refcount_inc(&cookie->ref, &ref);

	trace_fscache_cookie(cookie->debug_id, ref + 1, where);

	return cookie;

}



/*

 * check the consistency between the netfs inode and the backing cache

 *
@@ -1003,7 +1014,7 @@ static int fscache_cookies_seq_show(struct seq_file *m, void *v) 
		   "%08x %08x %5u %5u %3u %s %03lx %-16s %px",

		   cookie->debug_id,

		   cookie->parent ? cookie->parent->debug_id : 0,

		   atomic_read(&cookie->usage),

		   refcount_read(&cookie->ref),

		   atomic_read(&cookie->n_children),

		   atomic_read(&cookie->n_active),

		   type,

fs/fscache/fsdef.c

+1 −1
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ static struct fscache_cookie_def fscache_fsdef_index_def = { 


struct fscache_cookie fscache_fsdef_index = {

	.debug_id	= 1,

	.usage		= ATOMIC_INIT(1),

	.ref		= REFCOUNT_INIT(1),

	.n_active	= ATOMIC_INIT(1),

	.lock		= __SPIN_LOCK_UNLOCKED(fscache_fsdef_index.lock),

	.backing_objects = HLIST_HEAD_INIT,

fs/fscache/internal.h

+9 −8
Original line number Diff line number Diff line
@@ -54,9 +54,18 @@ extern struct fscache_cookie *fscache_alloc_cookie(struct fscache_cookie *, 
						   const void *, size_t,

						   void *, loff_t);

extern struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *);

extern struct fscache_cookie *fscache_cookie_get(struct fscache_cookie *,

						 enum fscache_cookie_trace);

extern void fscache_cookie_put(struct fscache_cookie *,

			       enum fscache_cookie_trace);



static inline void fscache_cookie_see(struct fscache_cookie *cookie,

				      enum fscache_cookie_trace where)

{

	trace_fscache_cookie(cookie->debug_id, refcount_read(&cookie->ref),

			     where);

}



/*

 * fsdef.c

 */
@@ -286,14 +295,6 @@ static inline void fscache_raise_event(struct fscache_object *object, 
		fscache_enqueue_object(object);

}



static inline void fscache_cookie_get(struct fscache_cookie *cookie,

				      enum fscache_cookie_trace where)

{

	int usage = atomic_inc_return(&cookie->usage);



	trace_fscache_cookie(cookie->debug_id, usage, where);

}



/*

 * get an extra reference to a netfs retrieval context

 */

include/linux/fscache.h

+1 −1
Original line number Diff line number Diff line
@@ -123,7 +123,7 @@ struct fscache_netfs { 
 * - indices are created on disk just-in-time

 */

struct fscache_cookie {

	atomic_t			usage;		/* number of users of this cookie */

	refcount_t			ref;		/* number of users of this cookie */

	atomic_t			n_children;	/* number of children of this cookie */

	atomic_t			n_active;	/* number of active users of netfs ptrs */

	unsigned int			debug_id;