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- // SPDX-License-Identifier: GPL-2.0
- /*
- * tracing_map - lock-free map for tracing
- *
- * Copyright (C) 2015 Tom Zanussi <[email protected]>
- *
- * tracing_map implementation inspired by lock-free map algorithms
- * originated by Dr. Cliff Click:
- *
- * http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
- * http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf
- */
- #include <linux/vmalloc.h>
- #include <linux/jhash.h>
- #include <linux/slab.h>
- #include <linux/sort.h>
- #include <linux/kmemleak.h>
- #include "tracing_map.h"
- #include "trace.h"
- /*
- * NOTE: For a detailed description of the data structures used by
- * these functions (such as tracing_map_elt) please see the overview
- * of tracing_map data structures at the beginning of tracing_map.h.
- */
- /**
- * tracing_map_update_sum - Add a value to a tracing_map_elt's sum field
- * @elt: The tracing_map_elt
- * @i: The index of the given sum associated with the tracing_map_elt
- * @n: The value to add to the sum
- *
- * Add n to sum i associated with the specified tracing_map_elt
- * instance. The index i is the index returned by the call to
- * tracing_map_add_sum_field() when the tracing map was set up.
- */
- void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n)
- {
- atomic64_add(n, &elt->fields[i].sum);
- }
- /**
- * tracing_map_read_sum - Return the value of a tracing_map_elt's sum field
- * @elt: The tracing_map_elt
- * @i: The index of the given sum associated with the tracing_map_elt
- *
- * Retrieve the value of the sum i associated with the specified
- * tracing_map_elt instance. The index i is the index returned by the
- * call to tracing_map_add_sum_field() when the tracing map was set
- * up.
- *
- * Return: The sum associated with field i for elt.
- */
- u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i)
- {
- return (u64)atomic64_read(&elt->fields[i].sum);
- }
- /**
- * tracing_map_set_var - Assign a tracing_map_elt's variable field
- * @elt: The tracing_map_elt
- * @i: The index of the given variable associated with the tracing_map_elt
- * @n: The value to assign
- *
- * Assign n to variable i associated with the specified tracing_map_elt
- * instance. The index i is the index returned by the call to
- * tracing_map_add_var() when the tracing map was set up.
- */
- void tracing_map_set_var(struct tracing_map_elt *elt, unsigned int i, u64 n)
- {
- atomic64_set(&elt->vars[i], n);
- elt->var_set[i] = true;
- }
- /**
- * tracing_map_var_set - Return whether or not a variable has been set
- * @elt: The tracing_map_elt
- * @i: The index of the given variable associated with the tracing_map_elt
- *
- * Return true if the variable has been set, false otherwise. The
- * index i is the index returned by the call to tracing_map_add_var()
- * when the tracing map was set up.
- */
- bool tracing_map_var_set(struct tracing_map_elt *elt, unsigned int i)
- {
- return elt->var_set[i];
- }
- /**
- * tracing_map_read_var - Return the value of a tracing_map_elt's variable field
- * @elt: The tracing_map_elt
- * @i: The index of the given variable associated with the tracing_map_elt
- *
- * Retrieve the value of the variable i associated with the specified
- * tracing_map_elt instance. The index i is the index returned by the
- * call to tracing_map_add_var() when the tracing map was set
- * up.
- *
- * Return: The variable value associated with field i for elt.
- */
- u64 tracing_map_read_var(struct tracing_map_elt *elt, unsigned int i)
- {
- return (u64)atomic64_read(&elt->vars[i]);
- }
- /**
- * tracing_map_read_var_once - Return and reset a tracing_map_elt's variable field
- * @elt: The tracing_map_elt
- * @i: The index of the given variable associated with the tracing_map_elt
- *
- * Retrieve the value of the variable i associated with the specified
- * tracing_map_elt instance, and reset the variable to the 'not set'
- * state. The index i is the index returned by the call to
- * tracing_map_add_var() when the tracing map was set up. The reset
- * essentially makes the variable a read-once variable if it's only
- * accessed using this function.
- *
- * Return: The variable value associated with field i for elt.
- */
- u64 tracing_map_read_var_once(struct tracing_map_elt *elt, unsigned int i)
- {
- elt->var_set[i] = false;
- return (u64)atomic64_read(&elt->vars[i]);
- }
- int tracing_map_cmp_string(void *val_a, void *val_b)
- {
- char *a = val_a;
- char *b = val_b;
- return strcmp(a, b);
- }
- int tracing_map_cmp_none(void *val_a, void *val_b)
- {
- return 0;
- }
- static int tracing_map_cmp_atomic64(void *val_a, void *val_b)
- {
- u64 a = atomic64_read((atomic64_t *)val_a);
- u64 b = atomic64_read((atomic64_t *)val_b);
- return (a > b) ? 1 : ((a < b) ? -1 : 0);
- }
- #define DEFINE_TRACING_MAP_CMP_FN(type) \
- static int tracing_map_cmp_##type(void *val_a, void *val_b) \
- { \
- type a = (type)(*(u64 *)val_a); \
- type b = (type)(*(u64 *)val_b); \
- \
- return (a > b) ? 1 : ((a < b) ? -1 : 0); \
- }
- DEFINE_TRACING_MAP_CMP_FN(s64);
- DEFINE_TRACING_MAP_CMP_FN(u64);
- DEFINE_TRACING_MAP_CMP_FN(s32);
- DEFINE_TRACING_MAP_CMP_FN(u32);
- DEFINE_TRACING_MAP_CMP_FN(s16);
- DEFINE_TRACING_MAP_CMP_FN(u16);
- DEFINE_TRACING_MAP_CMP_FN(s8);
- DEFINE_TRACING_MAP_CMP_FN(u8);
- tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size,
- int field_is_signed)
- {
- tracing_map_cmp_fn_t fn = tracing_map_cmp_none;
- switch (field_size) {
- case 8:
- if (field_is_signed)
- fn = tracing_map_cmp_s64;
- else
- fn = tracing_map_cmp_u64;
- break;
- case 4:
- if (field_is_signed)
- fn = tracing_map_cmp_s32;
- else
- fn = tracing_map_cmp_u32;
- break;
- case 2:
- if (field_is_signed)
- fn = tracing_map_cmp_s16;
- else
- fn = tracing_map_cmp_u16;
- break;
- case 1:
- if (field_is_signed)
- fn = tracing_map_cmp_s8;
- else
- fn = tracing_map_cmp_u8;
- break;
- }
- return fn;
- }
- static int tracing_map_add_field(struct tracing_map *map,
- tracing_map_cmp_fn_t cmp_fn)
- {
- int ret = -EINVAL;
- if (map->n_fields < TRACING_MAP_FIELDS_MAX) {
- ret = map->n_fields;
- map->fields[map->n_fields++].cmp_fn = cmp_fn;
- }
- return ret;
- }
- /**
- * tracing_map_add_sum_field - Add a field describing a tracing_map sum
- * @map: The tracing_map
- *
- * Add a sum field to the key and return the index identifying it in
- * the map and associated tracing_map_elts. This is the index used
- * for instance to update a sum for a particular tracing_map_elt using
- * tracing_map_update_sum() or reading it via tracing_map_read_sum().
- *
- * Return: The index identifying the field in the map and associated
- * tracing_map_elts, or -EINVAL on error.
- */
- int tracing_map_add_sum_field(struct tracing_map *map)
- {
- return tracing_map_add_field(map, tracing_map_cmp_atomic64);
- }
- /**
- * tracing_map_add_var - Add a field describing a tracing_map var
- * @map: The tracing_map
- *
- * Add a var to the map and return the index identifying it in the map
- * and associated tracing_map_elts. This is the index used for
- * instance to update a var for a particular tracing_map_elt using
- * tracing_map_update_var() or reading it via tracing_map_read_var().
- *
- * Return: The index identifying the var in the map and associated
- * tracing_map_elts, or -EINVAL on error.
- */
- int tracing_map_add_var(struct tracing_map *map)
- {
- int ret = -EINVAL;
- if (map->n_vars < TRACING_MAP_VARS_MAX)
- ret = map->n_vars++;
- return ret;
- }
- /**
- * tracing_map_add_key_field - Add a field describing a tracing_map key
- * @map: The tracing_map
- * @offset: The offset within the key
- * @cmp_fn: The comparison function that will be used to sort on the key
- *
- * Let the map know there is a key and that if it's used as a sort key
- * to use cmp_fn.
- *
- * A key can be a subset of a compound key; for that purpose, the
- * offset param is used to describe where within the compound key
- * the key referenced by this key field resides.
- *
- * Return: The index identifying the field in the map and associated
- * tracing_map_elts, or -EINVAL on error.
- */
- int tracing_map_add_key_field(struct tracing_map *map,
- unsigned int offset,
- tracing_map_cmp_fn_t cmp_fn)
- {
- int idx = tracing_map_add_field(map, cmp_fn);
- if (idx < 0)
- return idx;
- map->fields[idx].offset = offset;
- map->key_idx[map->n_keys++] = idx;
- return idx;
- }
- static void tracing_map_array_clear(struct tracing_map_array *a)
- {
- unsigned int i;
- if (!a->pages)
- return;
- for (i = 0; i < a->n_pages; i++)
- memset(a->pages[i], 0, PAGE_SIZE);
- }
- static void tracing_map_array_free(struct tracing_map_array *a)
- {
- unsigned int i;
- if (!a)
- return;
- if (!a->pages)
- goto free;
- for (i = 0; i < a->n_pages; i++) {
- if (!a->pages[i])
- break;
- kmemleak_free(a->pages[i]);
- free_page((unsigned long)a->pages[i]);
- }
- kfree(a->pages);
- free:
- kfree(a);
- }
- static struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts,
- unsigned int entry_size)
- {
- struct tracing_map_array *a;
- unsigned int i;
- a = kzalloc(sizeof(*a), GFP_KERNEL);
- if (!a)
- return NULL;
- a->entry_size_shift = fls(roundup_pow_of_two(entry_size) - 1);
- a->entries_per_page = PAGE_SIZE / (1 << a->entry_size_shift);
- a->n_pages = n_elts / a->entries_per_page;
- if (!a->n_pages)
- a->n_pages = 1;
- a->entry_shift = fls(a->entries_per_page) - 1;
- a->entry_mask = (1 << a->entry_shift) - 1;
- a->pages = kcalloc(a->n_pages, sizeof(void *), GFP_KERNEL);
- if (!a->pages)
- goto free;
- for (i = 0; i < a->n_pages; i++) {
- a->pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
- if (!a->pages[i])
- goto free;
- kmemleak_alloc(a->pages[i], PAGE_SIZE, 1, GFP_KERNEL);
- }
- out:
- return a;
- free:
- tracing_map_array_free(a);
- a = NULL;
- goto out;
- }
- static void tracing_map_elt_clear(struct tracing_map_elt *elt)
- {
- unsigned i;
- for (i = 0; i < elt->map->n_fields; i++)
- if (elt->fields[i].cmp_fn == tracing_map_cmp_atomic64)
- atomic64_set(&elt->fields[i].sum, 0);
- for (i = 0; i < elt->map->n_vars; i++) {
- atomic64_set(&elt->vars[i], 0);
- elt->var_set[i] = false;
- }
- if (elt->map->ops && elt->map->ops->elt_clear)
- elt->map->ops->elt_clear(elt);
- }
- static void tracing_map_elt_init_fields(struct tracing_map_elt *elt)
- {
- unsigned int i;
- tracing_map_elt_clear(elt);
- for (i = 0; i < elt->map->n_fields; i++) {
- elt->fields[i].cmp_fn = elt->map->fields[i].cmp_fn;
- if (elt->fields[i].cmp_fn != tracing_map_cmp_atomic64)
- elt->fields[i].offset = elt->map->fields[i].offset;
- }
- }
- static void tracing_map_elt_free(struct tracing_map_elt *elt)
- {
- if (!elt)
- return;
- if (elt->map->ops && elt->map->ops->elt_free)
- elt->map->ops->elt_free(elt);
- kfree(elt->fields);
- kfree(elt->vars);
- kfree(elt->var_set);
- kfree(elt->key);
- kfree(elt);
- }
- static struct tracing_map_elt *tracing_map_elt_alloc(struct tracing_map *map)
- {
- struct tracing_map_elt *elt;
- int err = 0;
- elt = kzalloc(sizeof(*elt), GFP_KERNEL);
- if (!elt)
- return ERR_PTR(-ENOMEM);
- elt->map = map;
- elt->key = kzalloc(map->key_size, GFP_KERNEL);
- if (!elt->key) {
- err = -ENOMEM;
- goto free;
- }
- elt->fields = kcalloc(map->n_fields, sizeof(*elt->fields), GFP_KERNEL);
- if (!elt->fields) {
- err = -ENOMEM;
- goto free;
- }
- elt->vars = kcalloc(map->n_vars, sizeof(*elt->vars), GFP_KERNEL);
- if (!elt->vars) {
- err = -ENOMEM;
- goto free;
- }
- elt->var_set = kcalloc(map->n_vars, sizeof(*elt->var_set), GFP_KERNEL);
- if (!elt->var_set) {
- err = -ENOMEM;
- goto free;
- }
- tracing_map_elt_init_fields(elt);
- if (map->ops && map->ops->elt_alloc) {
- err = map->ops->elt_alloc(elt);
- if (err)
- goto free;
- }
- return elt;
- free:
- tracing_map_elt_free(elt);
- return ERR_PTR(err);
- }
- static struct tracing_map_elt *get_free_elt(struct tracing_map *map)
- {
- struct tracing_map_elt *elt = NULL;
- int idx;
- idx = atomic_inc_return(&map->next_elt);
- if (idx < map->max_elts) {
- elt = *(TRACING_MAP_ELT(map->elts, idx));
- if (map->ops && map->ops->elt_init)
- map->ops->elt_init(elt);
- }
- return elt;
- }
- static void tracing_map_free_elts(struct tracing_map *map)
- {
- unsigned int i;
- if (!map->elts)
- return;
- for (i = 0; i < map->max_elts; i++) {
- tracing_map_elt_free(*(TRACING_MAP_ELT(map->elts, i)));
- *(TRACING_MAP_ELT(map->elts, i)) = NULL;
- }
- tracing_map_array_free(map->elts);
- map->elts = NULL;
- }
- static int tracing_map_alloc_elts(struct tracing_map *map)
- {
- unsigned int i;
- map->elts = tracing_map_array_alloc(map->max_elts,
- sizeof(struct tracing_map_elt *));
- if (!map->elts)
- return -ENOMEM;
- for (i = 0; i < map->max_elts; i++) {
- *(TRACING_MAP_ELT(map->elts, i)) = tracing_map_elt_alloc(map);
- if (IS_ERR(*(TRACING_MAP_ELT(map->elts, i)))) {
- *(TRACING_MAP_ELT(map->elts, i)) = NULL;
- tracing_map_free_elts(map);
- return -ENOMEM;
- }
- }
- return 0;
- }
- static inline bool keys_match(void *key, void *test_key, unsigned key_size)
- {
- bool match = true;
- if (memcmp(key, test_key, key_size))
- match = false;
- return match;
- }
- static inline struct tracing_map_elt *
- __tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only)
- {
- u32 idx, key_hash, test_key;
- int dup_try = 0;
- struct tracing_map_entry *entry;
- struct tracing_map_elt *val;
- key_hash = jhash(key, map->key_size, 0);
- if (key_hash == 0)
- key_hash = 1;
- idx = key_hash >> (32 - (map->map_bits + 1));
- while (1) {
- idx &= (map->map_size - 1);
- entry = TRACING_MAP_ENTRY(map->map, idx);
- test_key = entry->key;
- if (test_key && test_key == key_hash) {
- val = READ_ONCE(entry->val);
- if (val &&
- keys_match(key, val->key, map->key_size)) {
- if (!lookup_only)
- atomic64_inc(&map->hits);
- return val;
- } else if (unlikely(!val)) {
- /*
- * The key is present. But, val (pointer to elt
- * struct) is still NULL. which means some other
- * thread is in the process of inserting an
- * element.
- *
- * On top of that, it's key_hash is same as the
- * one being inserted right now. So, it's
- * possible that the element has the same
- * key as well.
- */
- dup_try++;
- if (dup_try > map->map_size) {
- atomic64_inc(&map->drops);
- break;
- }
- continue;
- }
- }
- if (!test_key) {
- if (lookup_only)
- break;
- if (!cmpxchg(&entry->key, 0, key_hash)) {
- struct tracing_map_elt *elt;
- elt = get_free_elt(map);
- if (!elt) {
- atomic64_inc(&map->drops);
- entry->key = 0;
- break;
- }
- memcpy(elt->key, key, map->key_size);
- entry->val = elt;
- atomic64_inc(&map->hits);
- return entry->val;
- } else {
- /*
- * cmpxchg() failed. Loop around once
- * more to check what key was inserted.
- */
- dup_try++;
- continue;
- }
- }
- idx++;
- }
- return NULL;
- }
- /**
- * tracing_map_insert - Insert key and/or retrieve val from a tracing_map
- * @map: The tracing_map to insert into
- * @key: The key to insert
- *
- * Inserts a key into a tracing_map and creates and returns a new
- * tracing_map_elt for it, or if the key has already been inserted by
- * a previous call, returns the tracing_map_elt already associated
- * with it. When the map was created, the number of elements to be
- * allocated for the map was specified (internally maintained as
- * 'max_elts' in struct tracing_map), and that number of
- * tracing_map_elts was created by tracing_map_init(). This is the
- * pre-allocated pool of tracing_map_elts that tracing_map_insert()
- * will allocate from when adding new keys. Once that pool is
- * exhausted, tracing_map_insert() is useless and will return NULL to
- * signal that state. There are two user-visible tracing_map
- * variables, 'hits' and 'drops', which are updated by this function.
- * Every time an element is either successfully inserted or retrieved,
- * the 'hits' value is incremented. Every time an element insertion
- * fails, the 'drops' value is incremented.
- *
- * This is a lock-free tracing map insertion function implementing a
- * modified form of Cliff Click's basic insertion algorithm. It
- * requires the table size be a power of two. To prevent any
- * possibility of an infinite loop we always make the internal table
- * size double the size of the requested table size (max_elts * 2).
- * Likewise, we never reuse a slot or resize or delete elements - when
- * we've reached max_elts entries, we simply return NULL once we've
- * run out of entries. Readers can at any point in time traverse the
- * tracing map and safely access the key/val pairs.
- *
- * Return: the tracing_map_elt pointer val associated with the key.
- * If this was a newly inserted key, the val will be a newly allocated
- * and associated tracing_map_elt pointer val. If the key wasn't
- * found and the pool of tracing_map_elts has been exhausted, NULL is
- * returned and no further insertions will succeed.
- */
- struct tracing_map_elt *tracing_map_insert(struct tracing_map *map, void *key)
- {
- return __tracing_map_insert(map, key, false);
- }
- /**
- * tracing_map_lookup - Retrieve val from a tracing_map
- * @map: The tracing_map to perform the lookup on
- * @key: The key to look up
- *
- * Looks up key in tracing_map and if found returns the matching
- * tracing_map_elt. This is a lock-free lookup; see
- * tracing_map_insert() for details on tracing_map and how it works.
- * Every time an element is retrieved, the 'hits' value is
- * incremented. There is one user-visible tracing_map variable,
- * 'hits', which is updated by this function. Every time an element
- * is successfully retrieved, the 'hits' value is incremented. The
- * 'drops' value is never updated by this function.
- *
- * Return: the tracing_map_elt pointer val associated with the key.
- * If the key wasn't found, NULL is returned.
- */
- struct tracing_map_elt *tracing_map_lookup(struct tracing_map *map, void *key)
- {
- return __tracing_map_insert(map, key, true);
- }
- /**
- * tracing_map_destroy - Destroy a tracing_map
- * @map: The tracing_map to destroy
- *
- * Frees a tracing_map along with its associated array of
- * tracing_map_elts.
- *
- * Callers should make sure there are no readers or writers actively
- * reading or inserting into the map before calling this.
- */
- void tracing_map_destroy(struct tracing_map *map)
- {
- if (!map)
- return;
- tracing_map_free_elts(map);
- tracing_map_array_free(map->map);
- kfree(map);
- }
- /**
- * tracing_map_clear - Clear a tracing_map
- * @map: The tracing_map to clear
- *
- * Resets the tracing map to a cleared or initial state. The
- * tracing_map_elts are all cleared, and the array of struct
- * tracing_map_entry is reset to an initialized state.
- *
- * Callers should make sure there are no writers actively inserting
- * into the map before calling this.
- */
- void tracing_map_clear(struct tracing_map *map)
- {
- unsigned int i;
- atomic_set(&map->next_elt, -1);
- atomic64_set(&map->hits, 0);
- atomic64_set(&map->drops, 0);
- tracing_map_array_clear(map->map);
- for (i = 0; i < map->max_elts; i++)
- tracing_map_elt_clear(*(TRACING_MAP_ELT(map->elts, i)));
- }
- static void set_sort_key(struct tracing_map *map,
- struct tracing_map_sort_key *sort_key)
- {
- map->sort_key = *sort_key;
- }
- /**
- * tracing_map_create - Create a lock-free map and element pool
- * @map_bits: The size of the map (2 ** map_bits)
- * @key_size: The size of the key for the map in bytes
- * @ops: Optional client-defined tracing_map_ops instance
- * @private_data: Client data associated with the map
- *
- * Creates and sets up a map to contain 2 ** map_bits number of
- * elements (internally maintained as 'max_elts' in struct
- * tracing_map). Before using, map fields should be added to the map
- * with tracing_map_add_sum_field() and tracing_map_add_key_field().
- * tracing_map_init() should then be called to allocate the array of
- * tracing_map_elts, in order to avoid allocating anything in the map
- * insertion path. The user-specified map size reflects the maximum
- * number of elements that can be contained in the table requested by
- * the user - internally we double that in order to keep the table
- * sparse and keep collisions manageable.
- *
- * A tracing_map is a special-purpose map designed to aggregate or
- * 'sum' one or more values associated with a specific object of type
- * tracing_map_elt, which is attached by the map to a given key.
- *
- * tracing_map_create() sets up the map itself, and provides
- * operations for inserting tracing_map_elts, but doesn't allocate the
- * tracing_map_elts themselves, or provide a means for describing the
- * keys or sums associated with the tracing_map_elts. All
- * tracing_map_elts for a given map have the same set of sums and
- * keys, which are defined by the client using the functions
- * tracing_map_add_key_field() and tracing_map_add_sum_field(). Once
- * the fields are defined, the pool of elements allocated for the map
- * can be created, which occurs when the client code calls
- * tracing_map_init().
- *
- * When tracing_map_init() returns, tracing_map_elt elements can be
- * inserted into the map using tracing_map_insert(). When called,
- * tracing_map_insert() grabs a free tracing_map_elt from the pool, or
- * finds an existing match in the map and in either case returns it.
- * The client can then use tracing_map_update_sum() and
- * tracing_map_read_sum() to update or read a given sum field for the
- * tracing_map_elt.
- *
- * The client can at any point retrieve and traverse the current set
- * of inserted tracing_map_elts in a tracing_map, via
- * tracing_map_sort_entries(). Sorting can be done on any field,
- * including keys.
- *
- * See tracing_map.h for a description of tracing_map_ops.
- *
- * Return: the tracing_map pointer if successful, ERR_PTR if not.
- */
- struct tracing_map *tracing_map_create(unsigned int map_bits,
- unsigned int key_size,
- const struct tracing_map_ops *ops,
- void *private_data)
- {
- struct tracing_map *map;
- unsigned int i;
- if (map_bits < TRACING_MAP_BITS_MIN ||
- map_bits > TRACING_MAP_BITS_MAX)
- return ERR_PTR(-EINVAL);
- map = kzalloc(sizeof(*map), GFP_KERNEL);
- if (!map)
- return ERR_PTR(-ENOMEM);
- map->map_bits = map_bits;
- map->max_elts = (1 << map_bits);
- atomic_set(&map->next_elt, -1);
- map->map_size = (1 << (map_bits + 1));
- map->ops = ops;
- map->private_data = private_data;
- map->map = tracing_map_array_alloc(map->map_size,
- sizeof(struct tracing_map_entry));
- if (!map->map)
- goto free;
- map->key_size = key_size;
- for (i = 0; i < TRACING_MAP_KEYS_MAX; i++)
- map->key_idx[i] = -1;
- out:
- return map;
- free:
- tracing_map_destroy(map);
- map = ERR_PTR(-ENOMEM);
- goto out;
- }
- /**
- * tracing_map_init - Allocate and clear a map's tracing_map_elts
- * @map: The tracing_map to initialize
- *
- * Allocates a clears a pool of tracing_map_elts equal to the
- * user-specified size of 2 ** map_bits (internally maintained as
- * 'max_elts' in struct tracing_map). Before using, the map fields
- * should be added to the map with tracing_map_add_sum_field() and
- * tracing_map_add_key_field(). tracing_map_init() should then be
- * called to allocate the array of tracing_map_elts, in order to avoid
- * allocating anything in the map insertion path. The user-specified
- * map size reflects the max number of elements requested by the user
- * - internally we double that in order to keep the table sparse and
- * keep collisions manageable.
- *
- * See tracing_map.h for a description of tracing_map_ops.
- *
- * Return: the tracing_map pointer if successful, ERR_PTR if not.
- */
- int tracing_map_init(struct tracing_map *map)
- {
- int err;
- if (map->n_fields < 2)
- return -EINVAL; /* need at least 1 key and 1 val */
- err = tracing_map_alloc_elts(map);
- if (err)
- return err;
- tracing_map_clear(map);
- return err;
- }
- static int cmp_entries_dup(const void *A, const void *B)
- {
- const struct tracing_map_sort_entry *a, *b;
- int ret = 0;
- a = *(const struct tracing_map_sort_entry **)A;
- b = *(const struct tracing_map_sort_entry **)B;
- if (memcmp(a->key, b->key, a->elt->map->key_size))
- ret = 1;
- return ret;
- }
- static int cmp_entries_sum(const void *A, const void *B)
- {
- const struct tracing_map_elt *elt_a, *elt_b;
- const struct tracing_map_sort_entry *a, *b;
- struct tracing_map_sort_key *sort_key;
- struct tracing_map_field *field;
- tracing_map_cmp_fn_t cmp_fn;
- void *val_a, *val_b;
- int ret = 0;
- a = *(const struct tracing_map_sort_entry **)A;
- b = *(const struct tracing_map_sort_entry **)B;
- elt_a = a->elt;
- elt_b = b->elt;
- sort_key = &elt_a->map->sort_key;
- field = &elt_a->fields[sort_key->field_idx];
- cmp_fn = field->cmp_fn;
- val_a = &elt_a->fields[sort_key->field_idx].sum;
- val_b = &elt_b->fields[sort_key->field_idx].sum;
- ret = cmp_fn(val_a, val_b);
- if (sort_key->descending)
- ret = -ret;
- return ret;
- }
- static int cmp_entries_key(const void *A, const void *B)
- {
- const struct tracing_map_elt *elt_a, *elt_b;
- const struct tracing_map_sort_entry *a, *b;
- struct tracing_map_sort_key *sort_key;
- struct tracing_map_field *field;
- tracing_map_cmp_fn_t cmp_fn;
- void *val_a, *val_b;
- int ret = 0;
- a = *(const struct tracing_map_sort_entry **)A;
- b = *(const struct tracing_map_sort_entry **)B;
- elt_a = a->elt;
- elt_b = b->elt;
- sort_key = &elt_a->map->sort_key;
- field = &elt_a->fields[sort_key->field_idx];
- cmp_fn = field->cmp_fn;
- val_a = elt_a->key + field->offset;
- val_b = elt_b->key + field->offset;
- ret = cmp_fn(val_a, val_b);
- if (sort_key->descending)
- ret = -ret;
- return ret;
- }
- static void destroy_sort_entry(struct tracing_map_sort_entry *entry)
- {
- if (!entry)
- return;
- if (entry->elt_copied)
- tracing_map_elt_free(entry->elt);
- kfree(entry);
- }
- /**
- * tracing_map_destroy_sort_entries - Destroy an array of sort entries
- * @entries: The entries to destroy
- * @n_entries: The number of entries in the array
- *
- * Destroy the elements returned by a tracing_map_sort_entries() call.
- */
- void tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
- unsigned int n_entries)
- {
- unsigned int i;
- for (i = 0; i < n_entries; i++)
- destroy_sort_entry(entries[i]);
- vfree(entries);
- }
- static struct tracing_map_sort_entry *
- create_sort_entry(void *key, struct tracing_map_elt *elt)
- {
- struct tracing_map_sort_entry *sort_entry;
- sort_entry = kzalloc(sizeof(*sort_entry), GFP_KERNEL);
- if (!sort_entry)
- return NULL;
- sort_entry->key = key;
- sort_entry->elt = elt;
- return sort_entry;
- }
- static void detect_dups(struct tracing_map_sort_entry **sort_entries,
- int n_entries, unsigned int key_size)
- {
- unsigned int total_dups = 0;
- int i;
- void *key;
- if (n_entries < 2)
- return;
- sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *),
- (int (*)(const void *, const void *))cmp_entries_dup, NULL);
- key = sort_entries[0]->key;
- for (i = 1; i < n_entries; i++) {
- if (!memcmp(sort_entries[i]->key, key, key_size)) {
- total_dups++;
- continue;
- }
- key = sort_entries[i]->key;
- }
- WARN_ONCE(total_dups > 0,
- "Duplicates detected: %d\n", total_dups);
- }
- static bool is_key(struct tracing_map *map, unsigned int field_idx)
- {
- unsigned int i;
- for (i = 0; i < map->n_keys; i++)
- if (map->key_idx[i] == field_idx)
- return true;
- return false;
- }
- static void sort_secondary(struct tracing_map *map,
- const struct tracing_map_sort_entry **entries,
- unsigned int n_entries,
- struct tracing_map_sort_key *primary_key,
- struct tracing_map_sort_key *secondary_key)
- {
- int (*primary_fn)(const void *, const void *);
- int (*secondary_fn)(const void *, const void *);
- unsigned i, start = 0, n_sub = 1;
- if (is_key(map, primary_key->field_idx))
- primary_fn = cmp_entries_key;
- else
- primary_fn = cmp_entries_sum;
- if (is_key(map, secondary_key->field_idx))
- secondary_fn = cmp_entries_key;
- else
- secondary_fn = cmp_entries_sum;
- for (i = 0; i < n_entries - 1; i++) {
- const struct tracing_map_sort_entry **a = &entries[i];
- const struct tracing_map_sort_entry **b = &entries[i + 1];
- if (primary_fn(a, b) == 0) {
- n_sub++;
- if (i < n_entries - 2)
- continue;
- }
- if (n_sub < 2) {
- start = i + 1;
- n_sub = 1;
- continue;
- }
- set_sort_key(map, secondary_key);
- sort(&entries[start], n_sub,
- sizeof(struct tracing_map_sort_entry *),
- (int (*)(const void *, const void *))secondary_fn, NULL);
- set_sort_key(map, primary_key);
- start = i + 1;
- n_sub = 1;
- }
- }
- /**
- * tracing_map_sort_entries - Sort the current set of tracing_map_elts in a map
- * @map: The tracing_map
- * @sort_keys: The sort key to use for sorting
- * @n_sort_keys: hitcount, always have at least one
- * @sort_entries: outval: pointer to allocated and sorted array of entries
- *
- * tracing_map_sort_entries() sorts the current set of entries in the
- * map and returns the list of tracing_map_sort_entries containing
- * them to the client in the sort_entries param. The client can
- * access the struct tracing_map_elt element of interest directly as
- * the 'elt' field of a returned struct tracing_map_sort_entry object.
- *
- * The sort_key has only two fields: idx and descending. 'idx' refers
- * to the index of the field added via tracing_map_add_sum_field() or
- * tracing_map_add_key_field() when the tracing_map was initialized.
- * 'descending' is a flag that if set reverses the sort order, which
- * by default is ascending.
- *
- * The client should not hold on to the returned array but should use
- * it and call tracing_map_destroy_sort_entries() when done.
- *
- * Return: the number of sort_entries in the struct tracing_map_sort_entry
- * array, negative on error
- */
- int tracing_map_sort_entries(struct tracing_map *map,
- struct tracing_map_sort_key *sort_keys,
- unsigned int n_sort_keys,
- struct tracing_map_sort_entry ***sort_entries)
- {
- int (*cmp_entries_fn)(const void *, const void *);
- struct tracing_map_sort_entry *sort_entry, **entries;
- int i, n_entries, ret;
- entries = vmalloc(array_size(sizeof(sort_entry), map->max_elts));
- if (!entries)
- return -ENOMEM;
- for (i = 0, n_entries = 0; i < map->map_size; i++) {
- struct tracing_map_entry *entry;
- entry = TRACING_MAP_ENTRY(map->map, i);
- if (!entry->key || !entry->val)
- continue;
- entries[n_entries] = create_sort_entry(entry->val->key,
- entry->val);
- if (!entries[n_entries++]) {
- ret = -ENOMEM;
- goto free;
- }
- }
- if (n_entries == 0) {
- ret = 0;
- goto free;
- }
- if (n_entries == 1) {
- *sort_entries = entries;
- return 1;
- }
- detect_dups(entries, n_entries, map->key_size);
- if (is_key(map, sort_keys[0].field_idx))
- cmp_entries_fn = cmp_entries_key;
- else
- cmp_entries_fn = cmp_entries_sum;
- set_sort_key(map, &sort_keys[0]);
- sort(entries, n_entries, sizeof(struct tracing_map_sort_entry *),
- (int (*)(const void *, const void *))cmp_entries_fn, NULL);
- if (n_sort_keys > 1)
- sort_secondary(map,
- (const struct tracing_map_sort_entry **)entries,
- n_entries,
- &sort_keys[0],
- &sort_keys[1]);
- *sort_entries = entries;
- return n_entries;
- free:
- tracing_map_destroy_sort_entries(entries, n_entries);
- return ret;
- }
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