Merge branch 'for-5.16-vsprintf-pgp' into for-linus

14 files changed, 223 insertions, 655 deletions

diff --git a/fs/fscache/Kconfig b/fs/fscache/Kconfig
index 427efa73b9bd..b313a978ae0a 100644
--- a/fs/fscache/Kconfig
+++ b/fs/fscache/Kconfig
@@ -14,6 +14,7 @@ config FSCACHE
 config FSCACHE_STATS
 	bool "Gather statistical information on local caching"
 	depends on FSCACHE && PROC_FS
+	select NETFS_STATS
 	help
 	  This option causes statistical information to be gathered on local
 	  caching and exported through file:
@@ -28,23 +29,6 @@ config FSCACHE_STATS
 
 	  See Documentation/filesystems/caching/fscache.rst for more information.
 
-config FSCACHE_HISTOGRAM
-	bool "Gather latency information on local caching"
-	depends on FSCACHE && PROC_FS
-	help
-	  This option causes latency information to be gathered on local
-	  caching and exported through file:
-
-		/proc/fs/fscache/histogram
-
-	  The generation of this histogram adds a certain amount of overhead to
-	  execution as there are a number of points at which data is gathered,
-	  and on a multi-CPU system these may be on cachelines that keep
-	  bouncing between CPUs.  On the other hand, the histogram may be
-	  useful for debugging purposes.  Saying 'N' here is recommended.
-
-	  See Documentation/filesystems/caching/fscache.rst for more information.
-
 config FSCACHE_DEBUG
 	bool "Debug FS-Cache"
 	depends on FSCACHE
@@ -54,10 +38,3 @@ config FSCACHE_DEBUG
 	  enabled by setting bits in /sys/modules/fscache/parameter/debug.
 
 	  See Documentation/filesystems/caching/fscache.rst for more information.
-
-config FSCACHE_OBJECT_LIST
-	bool "Maintain global object list for debugging purposes"
-	depends on FSCACHE && PROC_FS
-	help
-	  Maintain a global list of active fscache objects that can be
-	  retrieved through /proc/fs/fscache/objects for debugging purposes
diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile
index 3b2ffa93ac18..03a871d689bb 100644
--- a/fs/fscache/Makefile
+++ b/fs/fscache/Makefile
@@ -16,7 +16,5 @@ fscache-y := \
 
 fscache-$(CONFIG_PROC_FS) += proc.o
 fscache-$(CONFIG_FSCACHE_STATS) += stats.o
-fscache-$(CONFIG_FSCACHE_HISTOGRAM) += histogram.o
-fscache-$(CONFIG_FSCACHE_OBJECT_LIST) += object-list.o
 
 obj-$(CONFIG_FSCACHE) := fscache.o
diff --git a/fs/fscache/cache.c b/fs/fscache/cache.c
index fcc136361415..bd4f44c1cce0 100644
--- a/fs/fscache/cache.c
+++ b/fs/fscache/cache.c
@@ -116,7 +116,7 @@ struct fscache_cache *fscache_select_cache_for_object(
 			cache = NULL;
 
 		spin_unlock(&cookie->lock);
-		_leave(" = %p [parent]", cache);
+		_leave(" = %s [parent]", cache ? cache->tag->name : "NULL");
 		return cache;
 	}
 
@@ -152,14 +152,14 @@ struct fscache_cache *fscache_select_cache_for_object(
 	if (test_bit(FSCACHE_IOERROR, &tag->cache->flags))
 		return NULL;
 
-	_leave(" = %p [specific]", tag->cache);
+	_leave(" = %s [specific]", tag->name);
 	return tag->cache;
 
 no_preference:
 	/* netfs has no preference - just select first cache */
 	cache = list_entry(fscache_cache_list.next,
 			   struct fscache_cache, link);
-	_leave(" = %p [first]", cache);
+	_leave(" = %s [first]", cache->tag->name);
 	return cache;
 }
 
@@ -261,7 +261,6 @@ int fscache_add_cache(struct fscache_cache *cache,
 	spin_lock(&cache->object_list_lock);
 	list_add_tail(&ifsdef->cache_link, &cache->object_list);
 	spin_unlock(&cache->object_list_lock);
-	fscache_objlist_add(ifsdef);
 
 	/* add the cache's netfs definition index object to the top level index
 	 * cookie as a known backing object */
@@ -270,7 +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);
@@ -335,7 +334,7 @@ static void fscache_withdraw_all_objects(struct fscache_cache *cache,
 					    struct fscache_object, cache_link);
 			list_move_tail(&object->cache_link, dying_objects);
 
-			_debug("withdraw %p", object->cookie);
+			_debug("withdraw %x", object->cookie->debug_id);
 
 			/* This must be done under object_list_lock to prevent
 			 * a race with fscache_drop_object().
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 751bc5b1cddf..cd42be646ed3 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -19,6 +19,8 @@ static atomic_t fscache_object_debug_id = ATOMIC_INIT(0);
 
 #define fscache_cookie_hash_shift 15
 static struct hlist_bl_head fscache_cookie_hash[1 << fscache_cookie_hash_shift];
+static LIST_HEAD(fscache_cookies);
+static DEFINE_RWLOCK(fscache_cookies_lock);
 
 static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie,
 					    loff_t object_size);
@@ -29,21 +31,29 @@ static int fscache_attach_object(struct fscache_cookie *cookie,
 
 static void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
 {
-	struct hlist_node *object;
+	struct fscache_object *object;
+	struct hlist_node *o;
 	const u8 *k;
 	unsigned loop;
 
-	pr_err("%c-cookie c=%p [p=%p fl=%lx nc=%u na=%u]\n",
-	       prefix, cookie, cookie->parent, cookie->flags,
+	pr_err("%c-cookie c=%08x [p=%08x fl=%lx nc=%u na=%u]\n",
+	       prefix,
+	       cookie->debug_id,
+	       cookie->parent ? cookie->parent->debug_id : 0,
+	       cookie->flags,
 	       atomic_read(&cookie->n_children),
 	       atomic_read(&cookie->n_active));
-	pr_err("%c-cookie d=%p n=%p\n",
-	       prefix, cookie->def, cookie->netfs_data);
-
-	object = READ_ONCE(cookie->backing_objects.first);
-	if (object)
-		pr_err("%c-cookie o=%p\n",
-		       prefix, hlist_entry(object, struct fscache_object, cookie_link));
+	pr_err("%c-cookie d=%p{%s} n=%p\n",
+	       prefix,
+	       cookie->def,
+	       cookie->def ? cookie->def->name : "?",
+	       cookie->netfs_data);
+
+	o = READ_ONCE(cookie->backing_objects.first);
+	if (o) {
+		object = hlist_entry(o, struct fscache_object, cookie_link);
+		pr_err("%c-cookie o=%u\n", prefix, object->debug_id);
+	}
 
 	pr_err("%c-key=[%u] '", prefix, cookie->key_len);
 	k = (cookie->key_len <= sizeof(cookie->inline_key)) ?
@@ -57,6 +67,9 @@ void fscache_free_cookie(struct fscache_cookie *cookie)
 {
 	if (cookie) {
 		BUG_ON(!hlist_empty(&cookie->backing_objects));
+		write_lock(&fscache_cookies_lock);
+		list_del(&cookie->proc_link);
+		write_unlock(&fscache_cookies_lock);
 		if (cookie->aux_len > sizeof(cookie->inline_aux))
 			kfree(cookie->aux);
 		if (cookie->key_len > sizeof(cookie->inline_key))
@@ -74,10 +87,8 @@ void fscache_free_cookie(struct fscache_cookie *cookie)
 static int fscache_set_key(struct fscache_cookie *cookie,
 			   const void *index_key, size_t index_key_len)
 {
-	unsigned long long h;
 	u32 *buf;
 	int bufs;
-	int i;
 
 	bufs = DIV_ROUND_UP(index_key_len, sizeof(*buf));
 
@@ -91,17 +102,7 @@ static int fscache_set_key(struct fscache_cookie *cookie,
 	}
 
 	memcpy(buf, index_key, index_key_len);
-
-	/* Calculate a hash and combine this with the length in the first word
-	 * or first half word
-	 */
-	h = (unsigned long)cookie->parent;
-	h += index_key_len + cookie->type;
-
-	for (i = 0; i < bufs; i++)
-		h += buf[i];
-
-	cookie->key_hash = h ^ (h >> 32);
+	cookie->key_hash = fscache_hash(0, buf, bufs);
 	return 0;
 }
 
@@ -129,6 +130,8 @@ static long fscache_compare_cookie(const struct fscache_cookie *a,
 	return memcmp(ka, kb, a->key_len);
 }
 
+static atomic_t fscache_cookie_debug_id = ATOMIC_INIT(1);
+
 /*
  * Allocate a cookie.
  */
@@ -161,8 +164,9 @@ 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);
 
 	/* We keep the active count elevated until relinquishment to prevent an
 	 * attempt to wake up every time the object operations queue quiesces.
@@ -181,6 +185,10 @@ struct fscache_cookie *fscache_alloc_cookie(
 	/* radix tree insertion won't use the preallocation pool unless it's
 	 * told it may not wait */
 	INIT_RADIX_TREE(&cookie->stores, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
+
+	write_lock(&fscache_cookies_lock);
+	list_add_tail(&cookie->proc_link, &fscache_cookies);
+	write_unlock(&fscache_cookies_lock);
 	return cookie;
 
 nomem:
@@ -217,8 +225,8 @@ 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, fscache_cookie_collision,
-				     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');
 		fscache_print_cookie(candidate, 'N');
@@ -297,7 +305,8 @@ struct fscache_cookie *__fscache_acquire_cookie(
 
 	cookie = fscache_hash_cookie(candidate);
 	if (!cookie) {
-		trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
+		trace_fscache_cookie(candidate->debug_id, 1,
+				     fscache_cookie_discard);
 		goto out;
 	}
 
@@ -355,7 +364,7 @@ void __fscache_enable_cookie(struct fscache_cookie *cookie,
 			     bool (*can_enable)(void *data),
 			     void *data)
 {
-	_enter("%p", cookie);
+	_enter("%x", cookie->debug_id);
 
 	trace_fscache_enable(cookie);
 
@@ -452,10 +461,8 @@ static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie,
 
 	/* we may be required to wait for lookup to complete at this point */
 	if (!fscache_defer_lookup) {
-		_debug("non-deferred lookup %p", &cookie->flags);
 		wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
 			    TASK_UNINTERRUPTIBLE);
-		_debug("complete");
 		if (test_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags))
 			goto unavailable;
 	}
@@ -480,7 +487,7 @@ static int fscache_alloc_object(struct fscache_cache *cache,
 	struct fscache_object *object;
 	int ret;
 
-	_enter("%p,%p{%s}", cache, cookie, cookie->def->name);
+	_enter("%s,%x{%s}", cache->tag->name, cookie->debug_id, cookie->def->name);
 
 	spin_lock(&cookie->lock);
 	hlist_for_each_entry(object, &cookie->backing_objects,
@@ -600,8 +607,6 @@ static int fscache_attach_object(struct fscache_cookie *cookie,
 
 	/* Attach to the cookie.  The object already has a ref on it. */
 	hlist_add_head(&object->cookie_link, &cookie->backing_objects);
-
-	fscache_objlist_add(object);
 	ret = 0;
 
 cant_attach_object:
@@ -658,7 +663,7 @@ EXPORT_SYMBOL(__fscache_invalidate);
  */
 void __fscache_wait_on_invalidate(struct fscache_cookie *cookie)
 {
-	_enter("%p", cookie);
+	_enter("%x", cookie->debug_id);
 
 	wait_on_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING,
 		    TASK_UNINTERRUPTIBLE);
@@ -713,7 +718,7 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie,
 	struct fscache_object *object;
 	bool awaken = false;
 
-	_enter("%p,%u", cookie, invalidate);
+	_enter("%x,%u", cookie->debug_id, invalidate);
 
 	trace_fscache_disable(cookie);
 
@@ -803,8 +808,8 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie,
 		return;
 	}
 
-	_enter("%p{%s,%p,%d},%d",
-	       cookie, cookie->def->name, cookie->netfs_data,
+	_enter("%x{%s,%d},%d",
+	       cookie->debug_id, cookie->def->name,
 	       atomic_read(&cookie->n_active), retire);
 
 	trace_fscache_relinquish(cookie, retire);
@@ -821,13 +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("");
@@ -857,17 +861,17 @@ void fscache_cookie_put(struct fscache_cookie *cookie,
 			enum fscache_cookie_trace where)
 {
 	struct fscache_cookie *parent;
-	int usage;
+	int ref;
 
-	_enter("%p", cookie);
+	_enter("%x", cookie->debug_id);
 
 	do {
-		usage = atomic_dec_return(&cookie->usage);
-		trace_fscache_cookie(cookie, where, usage);
+		unsigned int cookie_debug_id = cookie->debug_id;
+		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);
@@ -881,6 +885,19 @@ void fscache_cookie_put(struct fscache_cookie *cookie,
 }
 
 /*
+ * 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
  *
  * NOTE: it only serves no-index type
@@ -958,3 +975,97 @@ inconsistent:
 	return -ESTALE;
 }
 EXPORT_SYMBOL(__fscache_check_consistency);
+
+/*
+ * Generate a list of extant cookies in /proc/fs/fscache/cookies
+ */
+static int fscache_cookies_seq_show(struct seq_file *m, void *v)
+{
+	struct fscache_cookie *cookie;
+	unsigned int keylen = 0, auxlen = 0;
+	char _type[3], *type;
+	u8 *p;
+
+	if (v == &fscache_cookies) {
+		seq_puts(m,
+			 "COOKIE   PARENT   USAGE CHILD ACT TY FL  DEF              NETFS_DATA\n"
+			 "======== ======== ===== ===== === == === ================ ==========\n"
+			 );
+		return 0;
+	}
+
+	cookie = list_entry(v, struct fscache_cookie, proc_link);
+
+	switch (cookie->type) {
+	case 0:
+		type = "IX";
+		break;
+	case 1:
+		type = "DT";
+		break;
+	default:
+		snprintf(_type, sizeof(_type), "%02u",
+			 cookie->type);
+		type = _type;
+		break;
+	}
+
+	seq_printf(m,
+		   "%08x %08x %5u %5u %3u %s %03lx %-16s %px",
+		   cookie->debug_id,
+		   cookie->parent ? cookie->parent->debug_id : 0,
+		   refcount_read(&cookie->ref),
+		   atomic_read(&cookie->n_children),
+		   atomic_read(&cookie->n_active),
+		   type,
+		   cookie->flags,
+		   cookie->def->name,
+		   cookie->netfs_data);
+
+	keylen = cookie->key_len;
+	auxlen = cookie->aux_len;
+
+	if (keylen > 0 || auxlen > 0) {
+		seq_puts(m, " ");
+		p = keylen <= sizeof(cookie->inline_key) ?
+			cookie->inline_key : cookie->key;
+		for (; keylen > 0; keylen--)
+			seq_printf(m, "%02x", *p++);
+		if (auxlen > 0) {
+			seq_puts(m, ", ");
+			p = auxlen <= sizeof(cookie->inline_aux) ?
+				cookie->inline_aux : cookie->aux;
+			for (; auxlen > 0; auxlen--)
+				seq_printf(m, "%02x", *p++);
+		}
+	}
+
+	seq_puts(m, "\n");
+	return 0;
+}
+
+static void *fscache_cookies_seq_start(struct seq_file *m, loff_t *_pos)
+	__acquires(fscache_cookies_lock)
+{
+	read_lock(&fscache_cookies_lock);
+	return seq_list_start_head(&fscache_cookies, *_pos);
+}
+
+static void *fscache_cookies_seq_next(struct seq_file *m, void *v, loff_t *_pos)
+{
+	return seq_list_next(v, &fscache_cookies, _pos);
+}
+
+static void fscache_cookies_seq_stop(struct seq_file *m, void *v)
+	__releases(rcu)
+{
+	read_unlock(&fscache_cookies_lock);
+}
+
+
+const struct seq_operations fscache_cookies_seq_ops = {
+	.start  = fscache_cookies_seq_start,
+	.next   = fscache_cookies_seq_next,
+	.stop   = fscache_cookies_seq_stop,
+	.show   = fscache_cookies_seq_show,
+};
diff --git a/fs/fscache/fsdef.c b/fs/fscache/fsdef.c
index 09ed8795ad86..0402673c680e 100644
--- a/fs/fscache/fsdef.c
+++ b/fs/fscache/fsdef.c
@@ -45,7 +45,8 @@ static struct fscache_cookie_def fscache_fsdef_index_def = {
 };
 
 struct fscache_cookie fscache_fsdef_index = {
-	.usage		= ATOMIC_INIT(1),
+	.debug_id	= 1,
+	.ref		= REFCOUNT_INIT(1),
 	.n_active	= ATOMIC_INIT(1),
 	.lock		= __SPIN_LOCK_UNLOCKED(fscache_fsdef_index.lock),
 	.backing_objects = HLIST_HEAD_INIT,
diff --git a/fs/fscache/histogram.c b/fs/fscache/histogram.c
deleted file mode 100644
index 4e5beeaaf454..000000000000
--- a/fs/fscache/histogram.c
+++ /dev/null
@@ -1,87 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* FS-Cache latency histogram
- *
- * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- */
-
-#define FSCACHE_DEBUG_LEVEL THREAD
-#include <linux/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include "internal.h"
-
-atomic_t fscache_obj_instantiate_histogram[HZ];
-atomic_t fscache_objs_histogram[HZ];
-atomic_t fscache_ops_histogram[HZ];
-atomic_t fscache_retrieval_delay_histogram[HZ];
-atomic_t fscache_retrieval_histogram[HZ];
-
-/*
- * display the time-taken histogram
- */
-static int fscache_histogram_show(struct seq_file *m, void *v)
-{
-	unsigned long index;
-	unsigned n[5], t;
-
-	switch ((unsigned long) v) {
-	case 1:
-		seq_puts(m, "JIFS  SECS  OBJ INST  OP RUNS   OBJ RUNS  RETRV DLY RETRIEVLS\n");
-		return 0;
-	case 2:
-		seq_puts(m, "===== ===== ========= ========= ========= ========= =========\n");
-		return 0;
-	default:
-		index = (unsigned long) v - 3;
-		n[0] = atomic_read(&fscache_obj_instantiate_histogram[index]);
-		n[1] = atomic_read(&fscache_ops_histogram[index]);
-		n[2] = atomic_read(&fscache_objs_histogram[index]);
-		n[3] = atomic_read(&fscache_retrieval_delay_histogram[index]);
-		n[4] = atomic_read(&fscache_retrieval_histogram[index]);
-		if (!(n[0] | n[1] | n[2] | n[3] | n[4]))
-			return 0;
-
-		t = (index * 1000) / HZ;
-
-		seq_printf(m, "%4lu  0.%03u %9u %9u %9u %9u %9u\n",
-			   index, t, n[0], n[1], n[2], n[3], n[4]);
-		return 0;
-	}
-}
-
-/*
- * set up the iterator to start reading from the first line
- */
-static void *fscache_histogram_start(struct seq_file *m, loff_t *_pos)
-{
-	if ((unsigned long long)*_pos >= HZ + 2)
-		return NULL;
-	if (*_pos == 0)
-		*_pos = 1;
-	return (void *)(unsigned long) *_pos;
-}
-
-/*
- * move to the next line
- */
-static void *fscache_histogram_next(struct seq_file *m, void *v, loff_t *pos)
-{
-	(*pos)++;
-	return (unsigned long long)*pos > HZ + 2 ?
-		NULL : (void *)(unsigned long) *pos;
-}
-
-/*
- * clean up after reading
- */
-static void fscache_histogram_stop(struct seq_file *m, void *v)
-{
-}
-
-const struct seq_operations fscache_histogram_ops = {
-	.start		= fscache_histogram_start,
-	.stop		= fscache_histogram_stop,
-	.next		= fscache_histogram_next,
-	.show		= fscache_histogram_show,
-};
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index c483863b740a..c3e4804b8fcb 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -45,6 +45,7 @@ extern struct fscache_cache *fscache_select_cache_for_object(
  * cookie.c
  */
 extern struct kmem_cache *fscache_cookie_jar;
+extern const struct seq_operations fscache_cookies_seq_ops;
 
 extern void fscache_free_cookie(struct fscache_cookie *);
 extern struct fscache_cookie *fscache_alloc_cookie(struct fscache_cookie *,
@@ -53,9 +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
  */
@@ -63,30 +73,6 @@ extern struct fscache_cookie fscache_fsdef_index;
 extern struct fscache_cookie_def fscache_fsdef_netfs_def;
 
 /*
- * histogram.c
- */
-#ifdef CONFIG_FSCACHE_HISTOGRAM
-extern atomic_t fscache_obj_instantiate_histogram[HZ];
-extern atomic_t fscache_objs_histogram[HZ];
-extern atomic_t fscache_ops_histogram[HZ];
-extern atomic_t fscache_retrieval_delay_histogram[HZ];
-extern atomic_t fscache_retrieval_histogram[HZ];
-
-static inline void fscache_hist(atomic_t histogram[], unsigned long start_jif)
-{
-	unsigned long jif = jiffies - start_jif;
-	if (jif >= HZ)
-		jif = HZ - 1;
-	atomic_inc(&histogram[jif]);
-}
-
-extern const struct seq_operations fscache_histogram_ops;
-
-#else
-#define fscache_hist(hist, start_jif) do {} while (0)
-#endif
-
-/*
  * main.c
  */
 extern unsigned fscache_defer_lookup;
@@ -97,6 +83,8 @@ extern struct workqueue_struct *fscache_object_wq;
 extern struct workqueue_struct *fscache_op_wq;
 DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
 
+extern unsigned int fscache_hash(unsigned int salt, unsigned int *data, unsigned int n);
+
 static inline bool fscache_object_congested(void)
 {
 	return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
@@ -108,19 +96,6 @@ static inline bool fscache_object_congested(void)
 extern void fscache_enqueue_object(struct fscache_object *);
 
 /*
- * object-list.c
- */
-#ifdef CONFIG_FSCACHE_OBJECT_LIST
-extern const struct proc_ops fscache_objlist_proc_ops;
-
-extern void fscache_objlist_add(struct fscache_object *);
-extern void fscache_objlist_remove(struct fscache_object *);
-#else
-#define fscache_objlist_add(object) do {} while(0)
-#define fscache_objlist_remove(object) do {} while(0)
-#endif
-
-/*
  * operation.c
  */
 extern int fscache_submit_exclusive_op(struct fscache_object *,
@@ -320,14 +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, where, usage);
-}
-
 /*
  * get an extra reference to a netfs retrieval context
  */
diff --git a/fs/fscache/main.c b/fs/fscache/main.c
index c1e6cc9091aa..4207f98e405f 100644
--- a/fs/fscache/main.c
+++ b/fs/fscache/main.c
@@ -94,6 +94,45 @@ static struct ctl_table fscache_sysctls_root[] = {
 #endif
 
 /*
+ * Mixing scores (in bits) for (7,20):
+ * Input delta: 1-bit      2-bit
+ * 1 round:     330.3     9201.6
+ * 2 rounds:   1246.4    25475.4
+ * 3 rounds:   1907.1    31295.1
+ * 4 rounds:   2042.3    31718.6
+ * Perfect:    2048      31744
+ *            (32*64)   (32*31/2 * 64)
+ */
+#define HASH_MIX(x, y, a)	\
+	(	x ^= (a),	\
+	y ^= x,	x = rol32(x, 7),\
+	x += y,	y = rol32(y,20),\
+	y *= 9			)
+
+static inline unsigned int fold_hash(unsigned long x, unsigned long y)
+{
+	/* Use arch-optimized multiply if one exists */
+	return __hash_32(y ^ __hash_32(x));
+}
+
+/*
+ * Generate a hash.  This is derived from full_name_hash(), but we want to be
+ * sure it is arch independent and that it doesn't change as bits of the
+ * computed hash value might appear on disk.  The caller also guarantees that
+ * the hashed data will be a series of aligned 32-bit words.
+ */
+unsigned int fscache_hash(unsigned int salt, unsigned int *data, unsigned int n)
+{
+	unsigned int a, x = 0, y = salt;
+
+	for (; n; n--) {
+		a = *data++;
+		HASH_MIX(x, y, a);
+	}
+	return fold_hash(x, y);
+}
+
+/*
  * initialise the fs caching module
  */
 static int __init fscache_init(void)
diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index cce92216fa28..d6bdb7b5e723 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -37,7 +37,7 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
 	if (!cookie)
 		goto already_registered;
 	if (cookie != candidate) {
-		trace_fscache_cookie(candidate, fscache_cookie_discard, 1);
+		trace_fscache_cookie(candidate->debug_id, 1, fscache_cookie_discard);
 		fscache_free_cookie(candidate);
 	}
 
diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
deleted file mode 100644
index e106a1a1600d..000000000000
--- a/fs/fscache/object-list.c
+++ /dev/null
@@ -1,414 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/* Global fscache object list maintainer and viewer
- *
- * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- */
-
-#define FSCACHE_DEBUG_LEVEL COOKIE
-#include <linux/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/slab.h>
-#include <linux/key.h>
-#include <keys/user-type.h>
-#include "internal.h"
-
-static struct rb_root fscache_object_list;
-static DEFINE_RWLOCK(fscache_object_list_lock);
-
-struct fscache_objlist_data {
-	unsigned long	config;		/* display configuration */
-#define FSCACHE_OBJLIST_CONFIG_KEY	0x00000001	/* show object keys */
-#define FSCACHE_OBJLIST_CONFIG_AUX	0x00000002	/* show object auxdata */
-#define FSCACHE_OBJLIST_CONFIG_COOKIE	0x00000004	/* show objects with cookies */
-#define FSCACHE_OBJLIST_CONFIG_NOCOOKIE	0x00000008	/* show objects without cookies */
-#define FSCACHE_OBJLIST_CONFIG_BUSY	0x00000010	/* show busy objects */
-#define FSCACHE_OBJLIST_CONFIG_IDLE	0x00000020	/* show idle objects */
-#define FSCACHE_OBJLIST_CONFIG_PENDWR	0x00000040	/* show objects with pending writes */
-#define FSCACHE_OBJLIST_CONFIG_NOPENDWR	0x00000080	/* show objects without pending writes */
-#define FSCACHE_OBJLIST_CONFIG_READS	0x00000100	/* show objects with active reads */
-#define FSCACHE_OBJLIST_CONFIG_NOREADS	0x00000200	/* show objects without active reads */
-#define FSCACHE_OBJLIST_CONFIG_EVENTS	0x00000400	/* show objects with events */
-#define FSCACHE_OBJLIST_CONFIG_NOEVENTS	0x00000800	/* show objects without no events */
-#define FSCACHE_OBJLIST_CONFIG_WORK	0x00001000	/* show objects with work */
-#define FSCACHE_OBJLIST_CONFIG_NOWORK	0x00002000	/* show objects without work */
-};
-
-/*
- * Add an object to the object list
- * - we use the address of the fscache_object structure as the key into the
- *   tree
- */
-void fscache_objlist_add(struct fscache_object *obj)
-{
-	struct fscache_object *xobj;
-	struct rb_node **p = &fscache_object_list.rb_node, *parent = NULL;
-
-	ASSERT(RB_EMPTY_NODE(&obj->objlist_link));
-
-	write_lock(&fscache_object_list_lock);
-
-	while (*p) {
-		parent = *p;
-		xobj = rb_entry(parent, struct fscache_object, objlist_link);
-
-		if (obj < xobj)
-			p = &(*p)->rb_left;
-		else if (obj > xobj)
-			p = &(*p)->rb_right;
-		else
-			BUG();
-	}
-
-	rb_link_node(&obj->objlist_link, parent, p);
-	rb_insert_color(&obj->objlist_link, &fscache_object_list);
-
-	write_unlock(&fscache_object_list_lock);
-}
-
-/*
- * Remove an object from the object list.
- */
-void fscache_objlist_remove(struct fscache_object *obj)
-{
-	if (RB_EMPTY_NODE(&obj->objlist_link))
-		return;
-
-	write_lock(&fscache_object_list_lock);
-
-	BUG_ON(RB_EMPTY_ROOT(&fscache_object_list));
-	rb_erase(&obj->objlist_link, &fscache_object_list);
-
-	write_unlock(&fscache_object_list_lock);
-}
-
-/*
- * find the object in the tree on or after the specified index
- */
-static struct fscache_object *fscache_objlist_lookup(loff_t *_pos)
-{
-	struct fscache_object *pobj, *obj = NULL, *minobj = NULL;
-	struct rb_node *p;
-	unsigned long pos;
-
-	if (*_pos >= (unsigned long) ERR_PTR(-ENOENT))
-		return NULL;
-	pos = *_pos;
-
-	/* banners (can't represent line 0 by pos 0 as that would involve
-	 * returning a NULL pointer) */
-	if (pos == 0)
-		return (struct fscache_object *)(long)++(*_pos);
-	if (pos < 3)
-		return (struct fscache_object *)pos;
-
-	pobj = (struct fscache_object *)pos;
-	p = fscache_object_list.rb_node;
-	while (p) {
-		obj = rb_entry(p, struct fscache_object, objlist_link);
-		if (pobj < obj) {
-			if (!minobj || minobj > obj)
-				minobj = obj;
-			p = p->rb_left;
-		} else if (pobj > obj) {
-			p = p->rb_right;
-		} else {
-			minobj = obj;
-			break;
-		}
-		obj = NULL;
-	}
-
-	if (!minobj)
-		*_pos = (unsigned long) ERR_PTR(-ENOENT);
-	else if (minobj != obj)
-		*_pos = (unsigned long) minobj;
-	return minobj;
-}
-
-/*
- * set up the iterator to start reading from the first line
- */
-static void *fscache_objlist_start(struct seq_file *m, loff_t *_pos)
-	__acquires(&fscache_object_list_lock)
-{
-	read_lock(&fscache_object_list_lock);
-	return fscache_objlist_lookup(_pos);
-}
-
-/*
- * move to the next line
- */
-static void *fscache_objlist_next(struct seq_file *m, void *v, loff_t *_pos)
-{
-	(*_pos)++;
-	return fscache_objlist_lookup(_pos);
-}
-
-/*
- * clean up after reading
- */
-static void fscache_objlist_stop(struct seq_file *m, void *v)
-	__releases(&fscache_object_list_lock)
-{
-	read_unlock(&fscache_object_list_lock);
-}
-
-/*
- * display an object
- */
-static int fscache_objlist_show(struct seq_file *m, void *v)
-{
-	struct fscache_objlist_data *data = m->private;
-	struct fscache_object *obj = v;
-	struct fscache_cookie *cookie;
-	unsigned long config = data->config;
-	char _type[3], *type;
-	u8 *p;
-
-	if ((unsigned long) v == 1) {
-		seq_puts(m, "OBJECT   PARENT   STAT CHLDN OPS OOP IPR EX READS"
-			 " EM EV FL S"
-			 " | NETFS_COOKIE_DEF TY FL NETFS_DATA");
-		if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
-			      FSCACHE_OBJLIST_CONFIG_AUX))
-			seq_puts(m, "       ");
-		if (config & FSCACHE_OBJLIST_CONFIG_KEY)
-			seq_puts(m, "OBJECT_KEY");
-		if ((config & (FSCACHE_OBJLIST_CONFIG_KEY |
-			       FSCACHE_OBJLIST_CONFIG_AUX)) ==
-		    (FSCACHE_OBJLIST_CONFIG_KEY | FSCACHE_OBJLIST_CONFIG_AUX))
-			seq_puts(m, ", ");
-		if (config & FSCACHE_OBJLIST_CONFIG_AUX)
-			seq_puts(m, "AUX_DATA");
-		seq_puts(m, "\n");
-		return 0;
-	}
-
-	if ((unsigned long) v == 2) {
-		seq_puts(m, "======== ======== ==== ===== === === === == ====="
-			 " == == == ="
-			 " | ================ == == ================");
-		if (config & (FSCACHE_OBJLIST_CONFIG_KEY |
-			      FSCACHE_OBJLIST_CONFIG_AUX))
-			seq_puts(m, " ================");
-		seq_puts(m, "\n");
-		return 0;
-	}
-
-	/* filter out any unwanted objects */
-#define FILTER(criterion, _yes, _no)					\
-	do {								\
-		unsigned long yes = FSCACHE_OBJLIST_CONFIG_##_yes;	\
-		unsigned long no = FSCACHE_OBJLIST_CONFIG_##_no;	\
-		if (criterion) {					\
-			if (!(config & yes))				\
-				return 0;				\
-		} else {						\
-			if (!(config & no))				\
-				return 0;				\
-		}							\
-	} while(0)
-
-	cookie = obj->cookie;
-	if (~config) {
-		FILTER(cookie->def,
-		       COOKIE, NOCOOKIE);
-		FILTER(fscache_object_is_active(obj) ||
-		       obj->n_ops != 0 ||
-		       obj->n_obj_ops != 0 ||
-		       obj->flags ||
-		       !list_empty(&obj->dependents),
-		       BUSY, IDLE);
-		FILTER(test_bit(FSCACHE_OBJECT_PENDING_WRITE, &obj->flags),
-		       PENDWR, NOPENDWR);
-		FILTER(atomic_read(&obj->n_reads),
-		       READS, NOREADS);
-		FILTER(obj->events & obj->event_mask,
-		       EVENTS, NOEVENTS);
-		FILTER(work_busy(&obj->work), WORK, NOWORK);
-	}
-
-	seq_printf(m,
-		   "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %2lx %1x | ",
-		   obj->debug_id,
-		   obj->parent ? obj->parent->debug_id : -1,
-		   obj->state->short_name,
-		   obj->n_children,
-		   obj->n_ops,
-		   obj->n_obj_ops,
-		   obj->n_in_progress,
-		   obj->n_exclusive,
-		   atomic_read(&obj->n_reads),
-		   obj->event_mask,
-		   obj->events,
-		   obj->flags,
-		   work_busy(&obj->work));
-
-	if (fscache_use_cookie(obj)) {
-		uint16_t keylen = 0, auxlen = 0;
-
-		switch (cookie->type) {
-		case 0:
-			type = "IX";
-			break;
-		case 1:
-			type = "DT";
-			break;
-		default:
-			snprintf(_type, sizeof(_type), "%02u",
-				 cookie->type);
-			type = _type;
-			break;
-		}
-
-		seq_printf(m, "%-16s %s %2lx %16p",
-			   cookie->def->name,
-			   type,
-			   cookie->flags,
-			   cookie->netfs_data);
-
-		if (config & FSCACHE_OBJLIST_CONFIG_KEY)
-			keylen = cookie->key_len;
-
-		if (config & FSCACHE_OBJLIST_CONFIG_AUX)
-			auxlen = cookie->aux_len;
-
-		if (keylen > 0 || auxlen > 0) {
-			seq_puts(m, " ");
-			p = keylen <= sizeof(cookie->inline_key) ?
-				cookie->inline_key : cookie->key;
-			for (; keylen > 0; keylen--)
-				seq_printf(m, "%02x", *p++);
-			if (auxlen > 0) {
-				if (config & FSCACHE_OBJLIST_CONFIG_KEY)
-					seq_puts(m, ", ");
-				p = auxlen <= sizeof(cookie->inline_aux) ?
-					cookie->inline_aux : cookie->aux;
-				for (; auxlen > 0; auxlen--)
-					seq_printf(m, "%02x", *p++);
-			}
-		}
-
-		seq_puts(m, "\n");
-		fscache_unuse_cookie(obj);
-	} else {
-		seq_puts(m, "<no_netfs>\n");
-	}
-	return 0;
-}
-
-static const struct seq_operations fscache_objlist_ops = {
-	.start		= fscache_objlist_start,
-	.stop		= fscache_objlist_stop,
-	.next		= fscache_objlist_next,
-	.show		= fscache_objlist_show,
-};
-
-/*
- * get the configuration for filtering the list
- */
-static void fscache_objlist_config(struct fscache_objlist_data *data)
-{
-#ifdef CONFIG_KEYS
-	const struct user_key_payload *confkey;
-	unsigned long config;
-	struct key *key;
-	const char *buf;
-	int len;
-
-	key = request_key(&key_type_user, "fscache:objlist", NULL);
-	if (IS_ERR(key))
-		goto no_config;
-
-	config = 0;
-	rcu_read_lock();
-
-	confkey = user_key_payload_rcu(key);
-	if (!confkey) {
-		/* key was revoked */
-		rcu_read_unlock();
-		key_put(key);
-		goto no_config;
-	}
-
-	buf = confkey->data;
-
-	for (len = confkey->datalen - 1; len >= 0; len--) {
-		switch (buf[len]) {
-		case 'K': config |= FSCACHE_OBJLIST_CONFIG_KEY;		break;
-		case 'A': config |= FSCACHE_OBJLIST_CONFIG_AUX;		break;
-		case 'C': config |= FSCACHE_OBJLIST_CONFIG_COOKIE;	break;
-		case 'c': config |= FSCACHE_OBJLIST_CONFIG_NOCOOKIE;	break;
-		case 'B': config |= FSCACHE_OBJLIST_CONFIG_BUSY;	break;
-		case 'b': config |= FSCACHE_OBJLIST_CONFIG_IDLE;	break;
-		case 'W': config |= FSCACHE_OBJLIST_CONFIG_PENDWR;	break;
-		case 'w': config |= FSCACHE_OBJLIST_CONFIG_NOPENDWR;	break;
-		case 'R': config |= FSCACHE_OBJLIST_CONFIG_READS;	break;
-		case 'r': config |= FSCACHE_OBJLIST_CONFIG_NOREADS;	break;
-		case 'S': config |= FSCACHE_OBJLIST_CONFIG_WORK;	break;
-		case 's': config |= FSCACHE_OBJLIST_CONFIG_NOWORK;	break;
-		}
-	}
-
-	rcu_read_unlock();
-	key_put(key);
-
-	if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
-	    config   |= FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE;
-	if (!(config & (FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE)))
-	    config   |= FSCACHE_OBJLIST_CONFIG_BUSY | FSCACHE_OBJLIST_CONFIG_IDLE;
-	if (!(config & (FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR)))
-	    config   |= FSCACHE_OBJLIST_CONFIG_PENDWR | FSCACHE_OBJLIST_CONFIG_NOPENDWR;
-	if (!(config & (FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS)))
-	    config   |= FSCACHE_OBJLIST_CONFIG_READS | FSCACHE_OBJLIST_CONFIG_NOREADS;
-	if (!(config & (FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS)))
-	    config   |= FSCACHE_OBJLIST_CONFIG_EVENTS | FSCACHE_OBJLIST_CONFIG_NOEVENTS;
-	if (!(config & (FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK)))
-	    config   |= FSCACHE_OBJLIST_CONFIG_WORK | FSCACHE_OBJLIST_CONFIG_NOWORK;
-
-	data->config = config;
-	return;
-
-no_config:
-#endif
-	data->config = ULONG_MAX;
-}
-
-/*
- * open "/proc/fs/fscache/objects" to provide a list of active objects
- * - can be configured by a user-defined key added to the caller's keyrings
- */
-static int fscache_objlist_open(struct inode *inode, struct file *file)
-{
-	struct fscache_objlist_data *data;
-
-	data = __seq_open_private(file, &fscache_objlist_ops, sizeof(*data));
-	if (!data)
-		return -ENOMEM;
-
-	/* get the configuration key */
-	fscache_objlist_config(data);
-
-	return 0;
-}
-
-/*
- * clean up on close
- */
-static int fscache_objlist_release(struct inode *inode, struct file *file)
-{
-	struct seq_file *m = file->private_data;
-
-	kfree(m->private);
-	m->private = NULL;
-	return seq_release(inode, file);
-}
-
-const struct proc_ops fscache_objlist_proc_ops = {
-	.proc_open	= fscache_objlist_open,
-	.proc_read	= seq_read,
-	.proc_lseek	= seq_lseek,
-	.proc_release	= fscache_objlist_release,
-};
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index cb2146e02cd5..f346a78f4bd6 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -277,13 +277,10 @@ static void fscache_object_work_func(struct work_struct *work)
 {
 	struct fscache_object *object =
 		container_of(work, struct fscache_object, work);
-	unsigned long start;
 
 	_enter("{OBJ%x}", object->debug_id);
 
-	start = jiffies;
 	fscache_object_sm_dispatcher(object);
-	fscache_hist(fscache_objs_histogram, start);
 	fscache_put_object(object, fscache_obj_put_work);
 }
 
@@ -436,7 +433,6 @@ static const struct fscache_state *fscache_parent_ready(struct fscache_object *o
 	spin_lock(&parent->lock);
 	parent->n_ops++;
 	parent->n_obj_ops++;
-	object->lookup_jif = jiffies;
 	spin_unlock(&parent->lock);
 
 	_leave("");
@@ -522,7 +518,6 @@ void fscache_object_lookup_negative(struct fscache_object *object)
 		set_bit(FSCACHE_COOKIE_NO_DATA_YET, &cookie->flags);
 		clear_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags);
 
-		_debug("wake up lookup %p", &cookie->flags);
 		clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags);
 		wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP);
 	}
@@ -596,7 +591,6 @@ static const struct fscache_state *fscache_object_available(struct fscache_objec
 	object->cache->ops->lookup_complete(object);
 	fscache_stat_d(&fscache_n_cop_lookup_complete);
 
-	fscache_hist(fscache_obj_instantiate_histogram, object->lookup_jif);
 	fscache_stat(&fscache_n_object_avail);
 
 	_leave("");
@@ -799,8 +793,6 @@ static void fscache_put_object(struct fscache_object *object,
  */
 void fscache_object_destroy(struct fscache_object *object)
 {
-	fscache_objlist_remove(object);
-
 	/* We can get rid of the cookie now */
 	fscache_cookie_put(object->cookie, fscache_cookie_put_object);
 	object->cookie = NULL;
diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
index 4a5651d4904e..433877107700 100644
--- a/fs/fscache/operation.c
+++ b/fs/fscache/operation.c
@@ -616,7 +616,6 @@ void fscache_op_work_func(struct work_struct *work)
 {
 	struct fscache_operation *op =
 		container_of(work, struct fscache_operation, work);
-	unsigned long start;
 
 	_enter("{OBJ%x OP%x,%d}",
 	       op->object->debug_id, op->debug_id, atomic_read(&op->usage));
@@ -624,9 +623,7 @@ void fscache_op_work_func(struct work_struct *work)
 	trace_fscache_op(op->object->cookie, op, fscache_op_work);
 
 	ASSERT(op->processor != NULL);
-	start = jiffies;
 	op->processor(op);
-	fscache_hist(fscache_ops_histogram, start);
 	fscache_put_operation(op);
 
 	_leave("");
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 991b0a871744..27df94ef0e0b 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -289,7 +289,6 @@ static void fscache_release_retrieval_op(struct fscache_operation *_op)
 	ASSERTIFCMP(op->op.state != FSCACHE_OP_ST_INITIALISED,
 		    atomic_read(&op->n_pages), ==, 0);
 
-	fscache_hist(fscache_retrieval_histogram, op->start_time);
 	if (op->context)
 		fscache_put_context(op->cookie, op->context);
 
@@ -324,7 +323,6 @@ struct fscache_retrieval *fscache_alloc_retrieval(
 	op->mapping	= mapping;
 	op->end_io_func	= end_io_func;
 	op->context	= context;
-	op->start_time	= jiffies;
 	INIT_LIST_HEAD(&op->to_do);
 
 	/* Pin the netfs read context in case we need to do the actual netfs
@@ -340,8 +338,6 @@ struct fscache_retrieval *fscache_alloc_retrieval(
  */
 int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
 {
-	unsigned long jif;
-
 	_enter("");
 
 	if (!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags)) {
@@ -351,7 +347,6 @@ int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
 
 	fscache_stat(&fscache_n_retrievals_wait);
 
-	jif = jiffies;
 	if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
 			TASK_INTERRUPTIBLE) != 0) {
 		fscache_stat(&fscache_n_retrievals_intr);
@@ -362,7 +357,6 @@ int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
 	ASSERT(!test_bit(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags));
 
 	smp_rmb();
-	fscache_hist(fscache_retrieval_delay_histogram, jif);
 	_leave(" = 0 [dly]");
 	return 0;
 }
diff --git a/fs/fscache/proc.c b/fs/fscache/proc.c
index 90a7bc22f7e1..061df8f61ffc 100644
--- a/fs/fscache/proc.c
+++ b/fs/fscache/proc.c
@@ -21,18 +21,16 @@ int __init fscache_proc_init(void)
 	if (!proc_mkdir("fs/fscache", NULL))
 		goto error_dir;
 
+	if (!proc_create_seq("fs/fscache/cookies", S_IFREG | 0444, NULL,
+			     &fscache_cookies_seq_ops))
+		goto error_cookies;
+
 #ifdef CONFIG_FSCACHE_STATS
 	if (!proc_create_single("fs/fscache/stats", S_IFREG | 0444, NULL,
 			fscache_stats_show))
 		goto error_stats;
 #endif
 
-#ifdef CONFIG_FSCACHE_HISTOGRAM
-	if (!proc_create_seq("fs/fscache/histogram", S_IFREG | 0444, NULL,
-			 &fscache_histogram_ops))
-		goto error_histogram;
-#endif
-
 #ifdef CONFIG_FSCACHE_OBJECT_LIST
 	if (!proc_create("fs/fscache/objects", S_IFREG | 0444, NULL,
 			 &fscache_objlist_proc_ops))
@@ -45,14 +43,12 @@ int __init fscache_proc_init(void)
 #ifdef CONFIG_FSCACHE_OBJECT_LIST
 error_objects:
 #endif
-#ifdef CONFIG_FSCACHE_HISTOGRAM
-	remove_proc_entry("fs/fscache/histogram", NULL);
-error_histogram:
-#endif
 #ifdef CONFIG_FSCACHE_STATS
 	remove_proc_entry("fs/fscache/stats", NULL);
 error_stats:
 #endif
+	remove_proc_entry("fs/fscache/cookies", NULL);
+error_cookies:
 	remove_proc_entry("fs/fscache", NULL);
 error_dir:
 	_leave(" = -ENOMEM");
@@ -67,11 +63,9 @@ void fscache_proc_cleanup(void)
 #ifdef CONFIG_FSCACHE_OBJECT_LIST
 	remove_proc_entry("fs/fscache/objects", NULL);
 #endif
-#ifdef CONFIG_FSCACHE_HISTOGRAM
-	remove_proc_entry("fs/fscache/histogram", NULL);
-#endif
 #ifdef CONFIG_FSCACHE_STATS
 	remove_proc_entry("fs/fscache/stats", NULL);
 #endif
+	remove_proc_entry("fs/fscache/cookies", NULL);
 	remove_proc_entry("fs/fscache", NULL);
 }