From 22098763a10d9c1340827fcf6edab66f153b27f0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 13 Sep 2026 12:27:00 -0700 Subject: Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Don't destroy user event fields when removal fails User event fields are destroyed before the event is removed from visibility. But that can fail leaving the still visible event with no fields. Move the destroying of the fields to after the event is successfully removed from visibility. - Initialize function graph state is fork before calling copy_exec_state() For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, ftrace_graph_exit_task() will free the tasks ret_stack pointer. Since that pointer is still using the parent's ret_stack, it mistakenly frees the parent's pointer too. Call ftrace_graph_init() on the task first which will NULL out the new tasks's ret_stack and if the copy fails, it will not free anything. - Remove FGRAPH_MAX_INDEX The macro FGRAPH_MAX_INDEX was added but never used. Remove it. - Save ent_size in function graph printing of nested functions The function graph tracer needs to look at the next event to see if the next event is the return of the current function entry. If it is, it prints a single line: ktime_get(); Otherwise it prints it like a nested function: tick_nohz_irq_exit() { ktime_get(); kcpustat_irq_exit(); } In order to look at the next event, it must save the current event so that it has the information to print from it. It saves the event in the iterator descriptor called "ent". What it doesn't save is the ent_size of the event which is now used to know if the function graph arguments are to be printed. The peek doesn't save the size so the size used happens to be that of the size of the last event that was seen. Save the entry event size in the iterator descriptor so that the correct size is used. - Fix several errors with freeing data in the histogram code The histogram code had a lot of leaked or or incorrect accounting when failures happen. Correct them. - Fix histogram regression of .percent and .graph modifiers Up until 6.3 histogram values could have "percent" or "graph" modifiers that changed how they were printed. But a change that added restricting histograms values from being strings, stack traces and other modifiers inadvertently prevented them from using the percent and graph modifiers, which were legal use cases for values. Put back the percent and graph modifiers. - Fix various typos in the comments - Set the trace_clock before initializing a histogram with clock argument The histogram API allows the user to specific which trace clock to use via a "clock=" string. The histogram is set up first before the clock is checked. If the passed in clock is not valid, it exits without fully fixing up the histogram leaving it on the list and a use-after-free can trigger. Update the clock argument first and if it fails then exit gracefully before the histogram trigger is placed on any lists. - Restore :mod: trailer after parsing in ftrace_set_clr_event The function ftrace_set_clr_event() modifies the parse string and needs to put it back to what was passed in. It searches for ":mod:" via a strsep() but fails to put back the first ':' in the string. Add back the ':' in the passed in string. - Take trace_array reference when opening a tracer options file The options files are dynamically created and some tracers add their own options. When a tracer adds their own list of options, the trace_array holding them has an array to hold the list of options for each tracer. This array increases in size via a krealloc(), and the new entry gets a newly allocated array to hold the options of the new tracer being added. The element in each entry of the tracer's option array holds a pointer back to the trace_array, a pointer to the tracer it is associated to, a pointer to the flags of the option. The issue is that these arrays are freed when the trace_array is freed when its instance it represents is removed from the instances directory. There's a race that an open of one of these options files can happen when the instance is being removed. Add a new helper function to be called by the open function of the options file to iterate all existing trace_arrays under a lock and find the one that has the given option element in one of it's tracer arrays. If found, then update the associated trace_array's reference counter to keep it from being freed. If not found, have the open call return -ENODEV. - Disable interrupts when acquiring the lock in rb_wake_up_waiters() The function rb_wake_up_waiters() assumes it will be called in interrupt context and does not disable irqs when taking cpu_buffer->reader_lock, which can be called in hard interrupt context. The issue is in PREEMPT_RT, this function is called in thread context leaving this lock open to a deadlock. Take the lock with interrupts disabled. - Use rcu_assign_pointer() for tmp_ops filter hash The tmp_ops used in update_ftrace_direct_mod() assigns its filter_hash field directly, but that field is annotated as __rcu and sparse complains. Assign it with rcu_assign_pointer() - Fix use-after-free in enable_trigger_private_data_free() The trace_event_call is accessed through the event_trigger_data's trace_event_file pointer to put the trace_event_call on freeing. The issue is that the trace_event_file data may have been freed already causing a use-after-free. Add a field to the event_trigger_data that points directly to the trace_event_call so that it can decrement its reference directly without needing to go through the trace_event_file. - Fix accounting of buffer data remote headers trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the number of pages is needed for the asked for size as it doesn't take into account the meta data on each page. Add a helper function to do the calculation properly and use that in these functions. - Catch nr_page_va overflow in ring_buffer_desc sizing The number of pages per remote ring buffer is capped by ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to overflow that field would silently allocate a descriptor smaller than what was asked for. - Do not resize the subbuf order if any per_cpu buffer is disabled The mmapping of ring buffers disables resizing the subbuffers, but it is done per-cpu whereas the subbuf size change is done for all the per_cpu buffers under the buffer->mutex. It could change the size of some while the mapping is happening on others. Have the resize of the subbuf order check all the per_cpu buffers under the lock to see if any of them is disabled before starting and causing an inconsistency between buffers that are being mapped. * tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits) ring-buffer: Check resize_disabled before publishing the new subbuf order tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing tracing/remotes: Account for ring buffer page header in size calculation tracing: Don't dereference trace_event_file in deferred trigger free ftrace: Use rcu_assign_pointer() for tmp_ops filter hash ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() tracing: Take trace_array reference when opening a tracer options file tracing: Fix ring_buffer_read_page_size() kernel-doc tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event() tracing: Fix memory corruption from a "STACKTRACE" histogram key tracing: Fix memory corruption from the histogram stacktrace modifier tracing: Undo the registration when enabling the histogram trigger fails tracing: Take the reference before publishing the named histogram trigger tracing: Set the trace clock before registering the histogram trigger tracing: Fix typo "preceeded" in comment tracing: Fix typo "availabe" in comment tracing: Let histogram values keep the percent and graph modifiers tracing: Keep the entry count when the histogram stats allocation fails tracing: Free histogram the field rejected for a bad modifier tracing: Free histogram the var ref when its initialization fails ... --- lib/lru_cache.c | 622 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 622 insertions(+) create mode 100644 lib/lru_cache.c (limited to 'lib/lru_cache.c') diff --git a/lib/lru_cache.c b/lib/lru_cache.c new file mode 100644 index 000000000..82f775044 --- /dev/null +++ b/lib/lru_cache.c @@ -0,0 +1,622 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + lru_cache.c + + This file is part of DRBD by Philipp Reisner and Lars Ellenberg. + + Copyright (C) 2003-2008, LINBIT Information Technologies GmbH. + Copyright (C) 2003-2008, Philipp Reisner . + Copyright (C) 2003-2008, Lars Ellenberg . + + + */ + +#include +#include +#include +#include /* for memset */ +#include /* for seq_printf */ +#include + +MODULE_AUTHOR("Philipp Reisner , " + "Lars Ellenberg "); +MODULE_DESCRIPTION("lru_cache - Track sets of hot objects"); +MODULE_LICENSE("GPL"); + +/* this is developers aid only. + * it catches concurrent access (lack of locking on the users part) */ +#define PARANOIA_ENTRY() do { \ + BUG_ON(!lc); \ + BUG_ON(!lc->nr_elements); \ + BUG_ON(test_and_set_bit(__LC_PARANOIA, &lc->flags)); \ +} while (0) + +#define RETURN(x...) do { \ + clear_bit_unlock(__LC_PARANOIA, &lc->flags); \ + return x ; } while (0) + +/* BUG() if e is not one of the elements tracked by lc */ +#define PARANOIA_LC_ELEMENT(lc, e) do { \ + struct lru_cache *lc_ = (lc); \ + struct lc_element *e_ = (e); \ + unsigned i = e_->lc_index; \ + BUG_ON(i >= lc_->nr_elements); \ + BUG_ON(lc_->lc_element[i] != e_); } while (0) + + +/* We need to atomically + * - try to grab the lock (set LC_LOCKED) + * - only if there is no pending transaction + * (neither LC_DIRTY nor LC_STARVING is set) + * Because of PARANOIA_ENTRY() above abusing lc->flags as well, + * it is not sufficient to just say + * return 0 == cmpxchg(&lc->flags, 0, LC_LOCKED); + */ +int lc_try_lock(struct lru_cache *lc) +{ + unsigned long val; + do { + val = cmpxchg(&lc->flags, 0, LC_LOCKED); + } while (unlikely (val == LC_PARANOIA)); + /* Spin until no-one is inside a PARANOIA_ENTRY()/RETURN() section. */ + return 0 == val; +} + +/** + * lc_create - prepares to track objects in an active set + * @name: descriptive name only used in lc_seq_printf_stats and lc_seq_dump_details + * @cache: cache root pointer + * @max_pending_changes: maximum changes to accumulate until a transaction is required + * @e_count: number of elements allowed to be active simultaneously + * @e_size: size of the tracked objects + * @e_off: offset to the &struct lc_element member in a tracked object + * + * Returns a pointer to a newly initialized struct lru_cache on success, + * or NULL on (allocation) failure. + */ +struct lru_cache *lc_create(const char *name, struct kmem_cache *cache, + unsigned max_pending_changes, + unsigned e_count, size_t e_size, size_t e_off) +{ + struct hlist_head *slot = NULL; + struct lc_element **element = NULL; + struct lru_cache *lc; + struct lc_element *e; + unsigned cache_obj_size = kmem_cache_size(cache); + unsigned i; + + WARN_ON(cache_obj_size < e_size); + if (cache_obj_size < e_size) + return NULL; + + /* e_count too big; would probably fail the allocation below anyways. + * for typical use cases, e_count should be few thousand at most. */ + if (e_count > LC_MAX_ACTIVE) + return NULL; + + slot = kzalloc_objs(struct hlist_head, e_count); + if (!slot) + goto out_fail; + element = kzalloc_objs(struct lc_element *, e_count); + if (!element) + goto out_fail; + + lc = kzalloc_obj(*lc); + if (!lc) + goto out_fail; + + INIT_LIST_HEAD(&lc->in_use); + INIT_LIST_HEAD(&lc->lru); + INIT_LIST_HEAD(&lc->free); + INIT_LIST_HEAD(&lc->to_be_changed); + + lc->name = name; + lc->element_size = e_size; + lc->element_off = e_off; + lc->nr_elements = e_count; + lc->max_pending_changes = max_pending_changes; + lc->lc_cache = cache; + lc->lc_element = element; + lc->lc_slot = slot; + + /* preallocate all objects */ + for (i = 0; i < e_count; i++) { + void *p = kmem_cache_alloc(cache, GFP_KERNEL); + if (!p) + break; + memset(p, 0, lc->element_size); + e = p + e_off; + e->lc_index = i; + e->lc_number = LC_FREE; + e->lc_new_number = LC_FREE; + list_add(&e->list, &lc->free); + element[i] = e; + } + if (i == e_count) + return lc; + + /* else: could not allocate all elements, give up */ + while (i) { + void *p = element[--i]; + kmem_cache_free(cache, p - e_off); + } + kfree(lc); +out_fail: + kfree(element); + kfree(slot); + return NULL; +} + +static void lc_free_by_index(struct lru_cache *lc, unsigned i) +{ + void *p = lc->lc_element[i]; + WARN_ON(!p); + if (p) { + p -= lc->element_off; + kmem_cache_free(lc->lc_cache, p); + } +} + +/** + * lc_destroy - frees memory allocated by lc_create() + * @lc: the lru cache to destroy + */ +void lc_destroy(struct lru_cache *lc) +{ + unsigned i; + if (!lc) + return; + for (i = 0; i < lc->nr_elements; i++) + lc_free_by_index(lc, i); + kfree(lc->lc_element); + kfree(lc->lc_slot); + kfree(lc); +} + +/** + * lc_reset - does a full reset for @lc and the hash table slots. + * @lc: the lru cache to operate on + * + * It is roughly the equivalent of re-allocating a fresh lru_cache object, + * basically a short cut to lc_destroy(lc); lc = lc_create(...); + */ +void lc_reset(struct lru_cache *lc) +{ + unsigned i; + + INIT_LIST_HEAD(&lc->in_use); + INIT_LIST_HEAD(&lc->lru); + INIT_LIST_HEAD(&lc->free); + INIT_LIST_HEAD(&lc->to_be_changed); + lc->used = 0; + lc->hits = 0; + lc->misses = 0; + lc->starving = 0; + lc->locked = 0; + lc->changed = 0; + lc->pending_changes = 0; + lc->flags = 0; + memset(lc->lc_slot, 0, sizeof(struct hlist_head) * lc->nr_elements); + + for (i = 0; i < lc->nr_elements; i++) { + struct lc_element *e = lc->lc_element[i]; + void *p = e; + p -= lc->element_off; + memset(p, 0, lc->element_size); + /* re-init it */ + e->lc_index = i; + e->lc_number = LC_FREE; + e->lc_new_number = LC_FREE; + list_add(&e->list, &lc->free); + } +} + +/** + * lc_seq_printf_stats - print stats about @lc into @seq + * @seq: the seq_file to print into + * @lc: the lru cache to print statistics of + */ +void lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc) +{ + /* NOTE: + * total calls to lc_get are + * (starving + hits + misses) + * misses include "locked" count (update from an other thread in + * progress) and "changed", when this in fact lead to an successful + * update of the cache. + */ + seq_printf(seq, "\t%s: used:%u/%u hits:%lu misses:%lu starving:%lu locked:%lu changed:%lu\n", + lc->name, lc->used, lc->nr_elements, + lc->hits, lc->misses, lc->starving, lc->locked, lc->changed); +} + +static struct hlist_head *lc_hash_slot(struct lru_cache *lc, unsigned int enr) +{ + return lc->lc_slot + (enr % lc->nr_elements); +} + + +static struct lc_element *__lc_find(struct lru_cache *lc, unsigned int enr, + bool include_changing) +{ + struct lc_element *e; + + BUG_ON(!lc); + BUG_ON(!lc->nr_elements); + hlist_for_each_entry(e, lc_hash_slot(lc, enr), collision) { + /* "about to be changed" elements, pending transaction commit, + * are hashed by their "new number". "Normal" elements have + * lc_number == lc_new_number. */ + if (e->lc_new_number != enr) + continue; + if (e->lc_new_number == e->lc_number || include_changing) + return e; + break; + } + return NULL; +} + +/** + * lc_find - find element by label, if present in the hash table + * @lc: The lru_cache object + * @enr: element number + * + * Returns the pointer to an element, if the element with the requested + * "label" or element number is present in the hash table, + * or NULL if not found. Does not change the refcnt. + * Ignores elements that are "about to be used", i.e. not yet in the active + * set, but still pending transaction commit. + */ +struct lc_element *lc_find(struct lru_cache *lc, unsigned int enr) +{ + return __lc_find(lc, enr, 0); +} + +/** + * lc_is_used - find element by label + * @lc: The lru_cache object + * @enr: element number + * + * Returns true, if the element with the requested "label" or element number is + * present in the hash table, and is used (refcnt > 0). + * Also finds elements that are not _currently_ used but only "about to be + * used", i.e. on the "to_be_changed" list, pending transaction commit. + */ +bool lc_is_used(struct lru_cache *lc, unsigned int enr) +{ + struct lc_element *e = __lc_find(lc, enr, 1); + return e && e->refcnt; +} + +/** + * lc_del - removes an element from the cache + * @lc: The lru_cache object + * @e: The element to remove + * + * @e must be unused (refcnt == 0). Moves @e from "lru" to "free" list, + * sets @e->enr to %LC_FREE. + */ +void lc_del(struct lru_cache *lc, struct lc_element *e) +{ + PARANOIA_ENTRY(); + PARANOIA_LC_ELEMENT(lc, e); + BUG_ON(e->refcnt); + + e->lc_number = e->lc_new_number = LC_FREE; + hlist_del_init(&e->collision); + list_move(&e->list, &lc->free); + RETURN(); +} + +static struct lc_element *lc_prepare_for_change(struct lru_cache *lc, unsigned new_number) +{ + struct list_head *n; + struct lc_element *e; + + if (!list_empty(&lc->free)) + n = lc->free.next; + else if (!list_empty(&lc->lru)) + n = lc->lru.prev; + else + return NULL; + + e = list_entry(n, struct lc_element, list); + PARANOIA_LC_ELEMENT(lc, e); + + e->lc_new_number = new_number; + if (!hlist_unhashed(&e->collision)) + __hlist_del(&e->collision); + hlist_add_head(&e->collision, lc_hash_slot(lc, new_number)); + list_move(&e->list, &lc->to_be_changed); + + return e; +} + +static int lc_unused_element_available(struct lru_cache *lc) +{ + if (!list_empty(&lc->free)) + return 1; /* something on the free list */ + if (!list_empty(&lc->lru)) + return 1; /* something to evict */ + + return 0; +} + +/* used as internal flags to __lc_get */ +enum { + LC_GET_MAY_CHANGE = 1, + LC_GET_MAY_USE_UNCOMMITTED = 2, +}; + +static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, unsigned int flags) +{ + struct lc_element *e; + + PARANOIA_ENTRY(); + if (test_bit(__LC_STARVING, &lc->flags)) { + ++lc->starving; + RETURN(NULL); + } + + e = __lc_find(lc, enr, 1); + /* if lc_new_number != lc_number, + * this enr is currently being pulled in already, + * and will be available once the pending transaction + * has been committed. */ + if (e) { + if (e->lc_new_number != e->lc_number) { + /* It has been found above, but on the "to_be_changed" + * list, not yet committed. Don't pull it in twice, + * wait for the transaction, then try again... + */ + if (!(flags & LC_GET_MAY_USE_UNCOMMITTED)) + RETURN(NULL); + /* ... unless the caller is aware of the implications, + * probably preparing a cumulative transaction. */ + ++e->refcnt; + ++lc->hits; + RETURN(e); + } + /* else: lc_new_number == lc_number; a real hit. */ + ++lc->hits; + if (e->refcnt++ == 0) + lc->used++; + list_move(&e->list, &lc->in_use); /* Not evictable... */ + RETURN(e); + } + /* e == NULL */ + + ++lc->misses; + if (!(flags & LC_GET_MAY_CHANGE)) + RETURN(NULL); + + /* To avoid races with lc_try_lock(), first, mark us dirty + * (using test_and_set_bit, as it implies memory barriers), ... */ + test_and_set_bit(__LC_DIRTY, &lc->flags); + + /* ... only then check if it is locked anyways. If lc_unlock clears + * the dirty bit again, that's not a problem, we will come here again. + */ + if (test_bit(__LC_LOCKED, &lc->flags)) { + ++lc->locked; + RETURN(NULL); + } + + /* In case there is nothing available and we can not kick out + * the LRU element, we have to wait ... + */ + if (!lc_unused_element_available(lc)) { + set_bit(__LC_STARVING, &lc->flags); + RETURN(NULL); + } + + /* It was not present in the active set. We are going to recycle an + * unused (or even "free") element, but we won't accumulate more than + * max_pending_changes changes. */ + if (lc->pending_changes >= lc->max_pending_changes) + RETURN(NULL); + + e = lc_prepare_for_change(lc, enr); + BUG_ON(!e); + + clear_bit(__LC_STARVING, &lc->flags); + BUG_ON(++e->refcnt != 1); + lc->used++; + lc->pending_changes++; + + RETURN(e); +} + +/** + * lc_get - get element by label, maybe change the active set + * @lc: the lru cache to operate on + * @enr: the label to look up + * + * Finds an element in the cache, increases its usage count, + * "touches" and returns it. + * + * In case the requested number is not present, it needs to be added to the + * cache. Therefore it is possible that an other element becomes evicted from + * the cache. In either case, the user is notified so he is able to e.g. keep + * a persistent log of the cache changes, and therefore the objects in use. + * + * Return values: + * NULL + * The cache was marked %LC_STARVING, + * or the requested label was not in the active set + * and a changing transaction is still pending (@lc was marked %LC_DIRTY). + * Or no unused or free element could be recycled (@lc will be marked as + * %LC_STARVING, blocking further lc_get() operations). + * + * pointer to the element with the REQUESTED element number. + * In this case, it can be used right away + * + * pointer to an UNUSED element with some different element number, + * where that different number may also be %LC_FREE. + * + * In this case, the cache is marked %LC_DIRTY, + * so lc_try_lock() will no longer succeed. + * The returned element pointer is moved to the "to_be_changed" list, + * and registered with the new element number on the hash collision chains, + * so it is possible to pick it up from lc_is_used(). + * Up to "max_pending_changes" (see lc_create()) can be accumulated. + * The user now should do whatever housekeeping is necessary, + * typically serialize on lc_try_lock_for_transaction(), then call + * lc_committed(lc) and lc_unlock(), to finish the change. + * + * NOTE: The user needs to check the lc_number on EACH use, so he recognizes + * any cache set change. + */ +struct lc_element *lc_get(struct lru_cache *lc, unsigned int enr) +{ + return __lc_get(lc, enr, LC_GET_MAY_CHANGE); +} + +/** + * lc_get_cumulative - like lc_get; also finds to-be-changed elements + * @lc: the lru cache to operate on + * @enr: the label to look up + * + * Unlike lc_get this also returns the element for @enr, if it is belonging to + * a pending transaction, so the return values are like for lc_get(), + * plus: + * + * pointer to an element already on the "to_be_changed" list. + * In this case, the cache was already marked %LC_DIRTY. + * + * Caller needs to make sure that the pending transaction is completed, + * before proceeding to actually use this element. + */ +struct lc_element *lc_get_cumulative(struct lru_cache *lc, unsigned int enr) +{ + return __lc_get(lc, enr, LC_GET_MAY_CHANGE|LC_GET_MAY_USE_UNCOMMITTED); +} + +/** + * lc_try_get - get element by label, if present; do not change the active set + * @lc: the lru cache to operate on + * @enr: the label to look up + * + * Finds an element in the cache, increases its usage count, + * "touches" and returns it. + * + * Return values: + * NULL + * The cache was marked %LC_STARVING, + * or the requested label was not in the active set + * + * pointer to the element with the REQUESTED element number. + * In this case, it can be used right away + */ +struct lc_element *lc_try_get(struct lru_cache *lc, unsigned int enr) +{ + return __lc_get(lc, enr, 0); +} + +/** + * lc_committed - tell @lc that pending changes have been recorded + * @lc: the lru cache to operate on + * + * User is expected to serialize on explicit lc_try_lock_for_transaction() + * before the transaction is started, and later needs to lc_unlock() explicitly + * as well. + */ +void lc_committed(struct lru_cache *lc) +{ + struct lc_element *e, *tmp; + + PARANOIA_ENTRY(); + list_for_each_entry_safe(e, tmp, &lc->to_be_changed, list) { + /* count number of changes, not number of transactions */ + ++lc->changed; + e->lc_number = e->lc_new_number; + list_move(&e->list, &lc->in_use); + } + lc->pending_changes = 0; + RETURN(); +} + + +/** + * lc_put - give up refcnt of @e + * @lc: the lru cache to operate on + * @e: the element to put + * + * If refcnt reaches zero, the element is moved to the lru list, + * and a %LC_STARVING (if set) is cleared. + * Returns the new (post-decrement) refcnt. + */ +unsigned int lc_put(struct lru_cache *lc, struct lc_element *e) +{ + PARANOIA_ENTRY(); + PARANOIA_LC_ELEMENT(lc, e); + BUG_ON(e->refcnt == 0); + BUG_ON(e->lc_number != e->lc_new_number); + if (--e->refcnt == 0) { + /* move it to the front of LRU. */ + list_move(&e->list, &lc->lru); + lc->used--; + clear_bit_unlock(__LC_STARVING, &lc->flags); + } + RETURN(e->refcnt); +} + +/** + * lc_element_by_index + * @lc: the lru cache to operate on + * @i: the index of the element to return + */ +struct lc_element *lc_element_by_index(struct lru_cache *lc, unsigned i) +{ + BUG_ON(i >= lc->nr_elements); + BUG_ON(lc->lc_element[i] == NULL); + BUG_ON(lc->lc_element[i]->lc_index != i); + return lc->lc_element[i]; +} + +/** + * lc_seq_dump_details - Dump a complete LRU cache to seq in textual form. + * @lc: the lru cache to operate on + * @seq: the &struct seq_file pointer to seq_printf into + * @utext: user supplied additional "heading" or other info + * @detail: function pointer the user may provide to dump further details + * of the object the lc_element is embedded in. May be NULL. + * Note: a leading space ' ' and trailing newline '\n' is implied. + */ +void lc_seq_dump_details(struct seq_file *seq, struct lru_cache *lc, char *utext, + void (*detail) (struct seq_file *, struct lc_element *)) +{ + unsigned int nr_elements = lc->nr_elements; + struct lc_element *e; + int i; + + seq_printf(seq, "\tnn: lc_number (new nr) refcnt %s\n ", utext); + for (i = 0; i < nr_elements; i++) { + e = lc_element_by_index(lc, i); + if (e->lc_number != e->lc_new_number) + seq_printf(seq, "\t%5d: %6d %8d %6d ", + i, e->lc_number, e->lc_new_number, e->refcnt); + else + seq_printf(seq, "\t%5d: %6d %-8s %6d ", + i, e->lc_number, "-\"-", e->refcnt); + if (detail) + detail(seq, e); + seq_putc(seq, '\n'); + } +} + +EXPORT_SYMBOL(lc_create); +EXPORT_SYMBOL(lc_reset); +EXPORT_SYMBOL(lc_destroy); +EXPORT_SYMBOL(lc_del); +EXPORT_SYMBOL(lc_try_get); +EXPORT_SYMBOL(lc_find); +EXPORT_SYMBOL(lc_get); +EXPORT_SYMBOL(lc_put); +EXPORT_SYMBOL(lc_committed); +EXPORT_SYMBOL(lc_element_by_index); +EXPORT_SYMBOL(lc_seq_printf_stats); +EXPORT_SYMBOL(lc_seq_dump_details); +EXPORT_SYMBOL(lc_try_lock); +EXPORT_SYMBOL(lc_is_used); +EXPORT_SYMBOL(lc_get_cumulative); -- cgit v1.3.1