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#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;
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;
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);}
static struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts, unsigned int entry_size){ struct tracing_map_array *a; unsigned int entry_size_shift; unsigned int entries_per_page; unsigned int n_pages; unsigned int i;
entry_size_shift = fls(roundup_pow_of_two(entry_size) - 1); entries_per_page = PAGE_SIZE / (1 << entry_size_shift); n_pages = max(1, n_elts / entries_per_page);
a = kzalloc_flex(*a, pages, n_pages); if (!a) return NULL;
a->entry_size_shift = entry_size_shift; a->entries_per_page = entries_per_page; a->n_pages = n_pages; a->entry_shift = fls(a->entries_per_page) - 1; a->entry_mask = (1 << a->entry_shift) - 1;
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;
kfree(elt->fields); kfree(elt->vars); kfree(elt->var_set); kfree(elt->key); kfree(elt);}
static void tracing_map_elt_free(struct tracing_map_elt *elt){ if (!elt) return;
/* Only objects initialized with alloc_elt() should be passed to free_elt().*/ if (elt->map->ops && elt->map->ops->elt_free) elt->map->ops->elt_free(elt); __tracing_map_elt_free(elt);}
static struct tracing_map_elt *tracing_map_elt_alloc(struct tracing_map *map){ struct tracing_map_elt *elt; int err = 0;
elt = kzalloc_obj(*elt); 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 = kzalloc_objs(*elt->fields, map->n_fields); if (!elt->fields) { err = -ENOMEM; goto free; }
elt->vars = kzalloc_objs(*elt->vars, map->n_vars); if (!elt->vars) { err = -ENOMEM; goto free; }
elt->var_set = kzalloc_objs(*elt->var_set, map->n_vars); 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_fetch_add_unless(&map->next_elt, 1, map->max_elts); 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); /* * Ensure the initialization is visible and * publish the elt. */ smp_wmb(); WRITE_ONCE(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, 0); 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_obj(*map); if (!map) return ERR_PTR(-ENOMEM);
map->map_bits = map_bits; map->max_elts = (1 << map_bits); atomic_set(&map->next_elt, 0);
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;
a = *(const struct tracing_map_sort_entry **)A; b = *(const struct tracing_map_sort_entry **)B;
return memcmp(a->key, b->key, a->elt->map->key_size);}
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_obj(*sort_entry); 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(map->max_elts, sizeof(sort_entry)); 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;}