| 0,0 → 1,1020 |
|---|
| /* |
| * 2002-10-18 written by Jim Houston jim.houston@ccur.com |
| * Copyright (C) 2002 by Concurrent Computer Corporation |
| * Distributed under the GNU GPL license version 2. |
| * |
| * Modified by George Anzinger to reuse immediately and to use |
| * find bit instructions. Also removed _irq on spinlocks. |
| * |
| * Modified by Nadia Derbey to make it RCU safe. |
| * |
| * Small id to pointer translation service. |
| * |
| * It uses a radix tree like structure as a sparse array indexed |
| * by the id to obtain the pointer. The bitmap makes allocating |
| * a new id quick. |
| * |
| * You call it to allocate an id (an int) an associate with that id a |
| * pointer or what ever, we treat it as a (void *). You can pass this |
| * id to a user for him to pass back at a later time. You then pass |
| * that id to this code and it returns your pointer. |
| |
| * You can release ids at any time. When all ids are released, most of |
| * the memory is returned (we keep IDR_FREE_MAX) in a local pool so we |
| * don't need to go to the memory "store" during an id allocate, just |
| * so you don't need to be too concerned about locking and conflicts |
| * with the slab allocator. |
| */ |
| |
| #include <linux/kernel.h> |
| |
| #include <linux/idr.h> |
| //#include <stdlib.h> |
| #include "drm.h" |
| #include "drmP.h" |
| #include "drm_crtc.h" |
| |
| unsigned long find_first_bit(const unsigned long *addr, unsigned long size) |
| { |
| const unsigned long *p = addr; |
| unsigned long result = 0; |
| unsigned long tmp; |
| |
| while (size & ~(BITS_PER_LONG-1)) { |
| if ((tmp = *(p++))) |
| goto found; |
| result += BITS_PER_LONG; |
| size -= BITS_PER_LONG; |
| } |
| if (!size) |
| return result; |
| |
| tmp = (*p) & (~0UL >> (BITS_PER_LONG - size)); |
| if (tmp == 0UL) /* Are any bits set? */ |
| return result + size; /* Nope. */ |
| found: |
| return result + __ffs(tmp); |
| } |
| |
| int find_next_bit(const unsigned long *addr, int size, int offset) |
| { |
| const unsigned long *p = addr + (offset >> 5); |
| int set = 0, bit = offset & 31, res; |
| |
| if (bit) |
| { |
| /* |
| * Look for nonzero in the first 32 bits: |
| */ |
| __asm__("bsfl %1,%0\n\t" |
| "jne 1f\n\t" |
| "movl $32, %0\n" |
| "1:" |
| : "=r" (set) |
| : "r" (*p >> bit)); |
| if (set < (32 - bit)) |
| return set + offset; |
| set = 32 - bit; |
| p++; |
| } |
| /* |
| * No set bit yet, search remaining full words for a bit |
| */ |
| res = find_first_bit (p, size - 32 * (p - addr)); |
| return (offset + set + res); |
| } |
| |
| #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) |
| |
| #define rcu_dereference(p) ({ \ |
| typeof(p) _________p1 = ACCESS_ONCE(p); \ |
| (_________p1); \ |
| }) |
| |
| #define rcu_assign_pointer(p, v) \ |
| ({ \ |
| if (!__builtin_constant_p(v) || \ |
| ((v) != NULL)) \ |
| (p) = (v); \ |
| }) |
| |
| //static struct kmem_cache *idr_layer_cache; |
| |
| |
| |
| |
| |
| static struct idr_layer *get_from_free_list(struct idr *idp) |
| { |
| struct idr_layer *p; |
| unsigned long flags; |
| |
| // spin_lock_irqsave(&idp->lock, flags); |
| if ((p = idp->id_free)) { |
| idp->id_free = p->ary[0]; |
| idp->id_free_cnt--; |
| p->ary[0] = NULL; |
| } |
| // spin_unlock_irqrestore(&idp->lock, flags); |
| return(p); |
| } |
| |
| |
| static void idr_layer_rcu_free(struct rcu_head *head) |
| { |
| struct idr_layer *layer; |
| |
| layer = container_of(head, struct idr_layer, rcu_head); |
| kfree(layer); |
| } |
| |
| |
| |
| static inline void free_layer(struct idr_layer *p) |
| { |
| kfree(p); |
| } |
| |
| |
| /* only called when idp->lock is held */ |
| static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
| { |
| p->ary[0] = idp->id_free; |
| idp->id_free = p; |
| idp->id_free_cnt++; |
| } |
| |
| static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
| { |
| unsigned long flags; |
| |
| /* |
| * Depends on the return element being zeroed. |
| */ |
| // spin_lock_irqsave(&idp->lock, flags); |
| __move_to_free_list(idp, p); |
| // spin_unlock_irqrestore(&idp->lock, flags); |
| } |
| |
| static void idr_mark_full(struct idr_layer **pa, int id) |
| { |
| struct idr_layer *p = pa[0]; |
| int l = 0; |
| |
| __set_bit(id & IDR_MASK, &p->bitmap); |
| /* |
| * If this layer is full mark the bit in the layer above to |
| * show that this part of the radix tree is full. This may |
| * complete the layer above and require walking up the radix |
| * tree. |
| */ |
| while (p->bitmap == IDR_FULL) { |
| if (!(p = pa[++l])) |
| break; |
| id = id >> IDR_BITS; |
| __set_bit((id & IDR_MASK), &p->bitmap); |
| } |
| } |
| |
| |
| |
| /** |
| * idr_pre_get - reserver resources for idr allocation |
| * @idp: idr handle |
| * @gfp_mask: memory allocation flags |
| * |
| * This function should be called prior to locking and calling the |
| * idr_get_new* functions. It preallocates enough memory to satisfy |
| * the worst possible allocation. |
| * |
| * If the system is REALLY out of memory this function returns 0, |
| * otherwise 1. |
| */ |
| int idr_pre_get(struct idr *idp, u32_t gfp_mask) |
| { |
| while (idp->id_free_cnt < IDR_FREE_MAX) { |
| struct idr_layer *new; |
| new = kzalloc(sizeof(struct idr_layer), gfp_mask); |
| if (new == NULL) |
| return (0); |
| move_to_free_list(idp, new); |
| } |
| return 1; |
| } |
| EXPORT_SYMBOL(idr_pre_get); |
| |
| |
| static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) |
| { |
| int n, m, sh; |
| struct idr_layer *p, *new; |
| int l, id, oid; |
| unsigned long bm; |
| |
| id = *starting_id; |
| restart: |
| p = idp->top; |
| l = idp->layers; |
| pa[l--] = NULL; |
| while (1) { |
| /* |
| * We run around this while until we reach the leaf node... |
| */ |
| n = (id >> (IDR_BITS*l)) & IDR_MASK; |
| bm = ~p->bitmap; |
| m = find_next_bit(&bm, IDR_SIZE, n); |
| if (m == IDR_SIZE) { |
| /* no space available go back to previous layer. */ |
| l++; |
| oid = id; |
| id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
| |
| /* if already at the top layer, we need to grow */ |
| if (!(p = pa[l])) { |
| *starting_id = id; |
| return IDR_NEED_TO_GROW; |
| } |
| |
| /* If we need to go up one layer, continue the |
| * loop; otherwise, restart from the top. |
| */ |
| sh = IDR_BITS * (l + 1); |
| if (oid >> sh == id >> sh) |
| continue; |
| else |
| goto restart; |
| } |
| if (m != n) { |
| sh = IDR_BITS*l; |
| id = ((id >> sh) ^ n ^ m) << sh; |
| } |
| if ((id >= MAX_ID_BIT) || (id < 0)) |
| return IDR_NOMORE_SPACE; |
| if (l == 0) |
| break; |
| /* |
| * Create the layer below if it is missing. |
| */ |
| if (!p->ary[m]) { |
| new = get_from_free_list(idp); |
| if (!new) |
| return -1; |
| new->layer = l-1; |
| rcu_assign_pointer(p->ary[m], new); |
| p->count++; |
| } |
| pa[l--] = p; |
| p = p->ary[m]; |
| } |
| |
| pa[l] = p; |
| return id; |
| } |
| |
| |
| static int idr_get_empty_slot(struct idr *idp, int starting_id, |
| struct idr_layer **pa) |
| { |
| struct idr_layer *p, *new; |
| int layers, v, id; |
| unsigned long flags; |
| |
| id = starting_id; |
| build_up: |
| p = idp->top; |
| layers = idp->layers; |
| if (unlikely(!p)) { |
| if (!(p = get_from_free_list(idp))) |
| return -1; |
| p->layer = 0; |
| layers = 1; |
| } |
| /* |
| * Add a new layer to the top of the tree if the requested |
| * id is larger than the currently allocated space. |
| */ |
| while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { |
| layers++; |
| if (!p->count) { |
| /* special case: if the tree is currently empty, |
| * then we grow the tree by moving the top node |
| * upwards. |
| */ |
| p->layer++; |
| continue; |
| } |
| if (!(new = get_from_free_list(idp))) { |
| /* |
| * The allocation failed. If we built part of |
| * the structure tear it down. |
| */ |
| // spin_lock_irqsave(&idp->lock, flags); |
| for (new = p; p && p != idp->top; new = p) { |
| p = p->ary[0]; |
| new->ary[0] = NULL; |
| new->bitmap = new->count = 0; |
| __move_to_free_list(idp, new); |
| } |
| // spin_unlock_irqrestore(&idp->lock, flags); |
| return -1; |
| } |
| new->ary[0] = p; |
| new->count = 1; |
| new->layer = layers-1; |
| if (p->bitmap == IDR_FULL) |
| __set_bit(0, &new->bitmap); |
| p = new; |
| } |
| rcu_assign_pointer(idp->top, p); |
| idp->layers = layers; |
| v = sub_alloc(idp, &id, pa); |
| if (v == IDR_NEED_TO_GROW) |
| goto build_up; |
| return(v); |
| } |
| |
| static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id) |
| { |
| struct idr_layer *pa[MAX_LEVEL]; |
| int id; |
| |
| id = idr_get_empty_slot(idp, starting_id, pa); |
| if (id >= 0) { |
| /* |
| * Successfully found an empty slot. Install the user |
| * pointer and mark the slot full. |
| */ |
| rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], |
| (struct idr_layer *)ptr); |
| pa[0]->count++; |
| idr_mark_full(pa, id); |
| } |
| |
| return id; |
| } |
| |
| /** |
| * idr_get_new_above - allocate new idr entry above or equal to a start id |
| * @idp: idr handle |
| * @ptr: pointer you want associated with the ide |
| * @start_id: id to start search at |
| * @id: pointer to the allocated handle |
| * |
| * This is the allocate id function. It should be called with any |
| * required locks. |
| * |
| * If memory is required, it will return -EAGAIN, you should unlock |
| * and go back to the idr_pre_get() call. If the idr is full, it will |
| * return -ENOSPC. |
| * |
| * @id returns a value in the range @starting_id ... 0x7fffffff |
| */ |
| int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) |
| { |
| int rv; |
| rv = idr_get_new_above_int(idp, ptr, starting_id); |
| /* |
| * This is a cheap hack until the IDR code can be fixed to |
| * return proper error values. |
| */ |
| if (rv < 0) |
| { |
| dbgprintf("fail\n"); |
| return _idr_rc_to_errno(rv); |
| }; |
| *id = rv; |
| return 0; |
| } |
| EXPORT_SYMBOL(idr_get_new_above); |
| |
| /** |
| * idr_get_new - allocate new idr entry |
| * @idp: idr handle |
| * @ptr: pointer you want associated with the ide |
| * @id: pointer to the allocated handle |
| * |
| * This is the allocate id function. It should be called with any |
| * required locks. |
| * |
| * If memory is required, it will return -EAGAIN, you should unlock |
| * and go back to the idr_pre_get() call. If the idr is full, it will |
| * return -ENOSPC. |
| * |
| * @id returns a value in the range 0 ... 0x7fffffff |
| */ |
| int idr_get_new(struct idr *idp, void *ptr, int *id) |
| { |
| int rv; |
| |
| rv = idr_get_new_above_int(idp, ptr, 0); |
| /* |
| * This is a cheap hack until the IDR code can be fixed to |
| * return proper error values. |
| */ |
| if (rv < 0) |
| return _idr_rc_to_errno(rv); |
| *id = rv; |
| return 0; |
| } |
| EXPORT_SYMBOL(idr_get_new); |
| |
| static void idr_remove_warning(int id) |
| { |
| printk(KERN_WARNING |
| "idr_remove called for id=%d which is not allocated.\n", id); |
| // dump_stack(); |
| } |
| |
| static void sub_remove(struct idr *idp, int shift, int id) |
| { |
| struct idr_layer *p = idp->top; |
| struct idr_layer **pa[MAX_LEVEL]; |
| struct idr_layer ***paa = &pa[0]; |
| struct idr_layer *to_free; |
| int n; |
| |
| *paa = NULL; |
| *++paa = &idp->top; |
| |
| while ((shift > 0) && p) { |
| n = (id >> shift) & IDR_MASK; |
| __clear_bit(n, &p->bitmap); |
| *++paa = &p->ary[n]; |
| p = p->ary[n]; |
| shift -= IDR_BITS; |
| } |
| n = id & IDR_MASK; |
| if (likely(p != NULL && test_bit(n, &p->bitmap))){ |
| __clear_bit(n, &p->bitmap); |
| rcu_assign_pointer(p->ary[n], NULL); |
| to_free = NULL; |
| while(*paa && ! --((**paa)->count)){ |
| if (to_free) |
| free_layer(to_free); |
| to_free = **paa; |
| **paa-- = NULL; |
| } |
| if (!*paa) |
| idp->layers = 0; |
| if (to_free) |
| free_layer(to_free); |
| } else |
| idr_remove_warning(id); |
| } |
| |
| /** |
| * idr_remove - remove the given id and free it's slot |
| * @idp: idr handle |
| * @id: unique key |
| */ |
| void idr_remove(struct idr *idp, int id) |
| { |
| struct idr_layer *p; |
| struct idr_layer *to_free; |
| |
| /* Mask off upper bits we don't use for the search. */ |
| id &= MAX_ID_MASK; |
| |
| sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
| if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
| idp->top->ary[0]) { |
| /* |
| * Single child at leftmost slot: we can shrink the tree. |
| * This level is not needed anymore since when layers are |
| * inserted, they are inserted at the top of the existing |
| * tree. |
| */ |
| to_free = idp->top; |
| p = idp->top->ary[0]; |
| rcu_assign_pointer(idp->top, p); |
| --idp->layers; |
| to_free->bitmap = to_free->count = 0; |
| free_layer(to_free); |
| } |
| while (idp->id_free_cnt >= IDR_FREE_MAX) { |
| p = get_from_free_list(idp); |
| /* |
| * Note: we don't call the rcu callback here, since the only |
| * layers that fall into the freelist are those that have been |
| * preallocated. |
| */ |
| kfree(p); |
| } |
| return; |
| } |
| EXPORT_SYMBOL(idr_remove); |
| |
| |
| /** |
| * idr_remove_all - remove all ids from the given idr tree |
| * @idp: idr handle |
| * |
| * idr_destroy() only frees up unused, cached idp_layers, but this |
| * function will remove all id mappings and leave all idp_layers |
| * unused. |
| * |
| * A typical clean-up sequence for objects stored in an idr tree, will |
| * use idr_for_each() to free all objects, if necessay, then |
| * idr_remove_all() to remove all ids, and idr_destroy() to free |
| * up the cached idr_layers. |
| */ |
| void idr_remove_all(struct idr *idp) |
| { |
| int n, id, max; |
| struct idr_layer *p; |
| struct idr_layer *pa[MAX_LEVEL]; |
| struct idr_layer **paa = &pa[0]; |
| |
| n = idp->layers * IDR_BITS; |
| p = idp->top; |
| rcu_assign_pointer(idp->top, NULL); |
| max = 1 << n; |
| |
| id = 0; |
| while (id < max) { |
| while (n > IDR_BITS && p) { |
| n -= IDR_BITS; |
| *paa++ = p; |
| p = p->ary[(id >> n) & IDR_MASK]; |
| } |
| |
| id += 1 << n; |
| while (n < fls(id)) { |
| if (p) |
| free_layer(p); |
| n += IDR_BITS; |
| p = *--paa; |
| } |
| } |
| idp->layers = 0; |
| } |
| EXPORT_SYMBOL(idr_remove_all); |
| |
| /** |
| * idr_destroy - release all cached layers within an idr tree |
| * idp: idr handle |
| */ |
| void idr_destroy(struct idr *idp) |
| { |
| while (idp->id_free_cnt) { |
| struct idr_layer *p = get_from_free_list(idp); |
| kfree(p); |
| } |
| } |
| EXPORT_SYMBOL(idr_destroy); |
| |
| |
| /** |
| * idr_find - return pointer for given id |
| * @idp: idr handle |
| * @id: lookup key |
| * |
| * Return the pointer given the id it has been registered with. A %NULL |
| * return indicates that @id is not valid or you passed %NULL in |
| * idr_get_new(). |
| * |
| * This function can be called under rcu_read_lock(), given that the leaf |
| * pointers lifetimes are correctly managed. |
| */ |
| void *idr_find(struct idr *idp, int id) |
| { |
| int n; |
| struct idr_layer *p; |
| |
| p = rcu_dereference(idp->top); |
| if (!p) |
| return NULL; |
| n = (p->layer+1) * IDR_BITS; |
| |
| /* Mask off upper bits we don't use for the search. */ |
| id &= MAX_ID_MASK; |
| |
| if (id >= (1 << n)) |
| return NULL; |
| BUG_ON(n == 0); |
| |
| while (n > 0 && p) { |
| n -= IDR_BITS; |
| BUG_ON(n != p->layer*IDR_BITS); |
| p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); |
| } |
| return((void *)p); |
| } |
| EXPORT_SYMBOL(idr_find); |
| |
| #if 0 |
| /** |
| * idr_for_each - iterate through all stored pointers |
| * @idp: idr handle |
| * @fn: function to be called for each pointer |
| * @data: data passed back to callback function |
| * |
| * Iterate over the pointers registered with the given idr. The |
| * callback function will be called for each pointer currently |
| * registered, passing the id, the pointer and the data pointer passed |
| * to this function. It is not safe to modify the idr tree while in |
| * the callback, so functions such as idr_get_new and idr_remove are |
| * not allowed. |
| * |
| * We check the return of @fn each time. If it returns anything other |
| * than 0, we break out and return that value. |
| * |
| * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). |
| */ |
| int idr_for_each(struct idr *idp, |
| int (*fn)(int id, void *p, void *data), void *data) |
| { |
| int n, id, max, error = 0; |
| struct idr_layer *p; |
| struct idr_layer *pa[MAX_LEVEL]; |
| struct idr_layer **paa = &pa[0]; |
| |
| n = idp->layers * IDR_BITS; |
| p = rcu_dereference(idp->top); |
| max = 1 << n; |
| |
| id = 0; |
| while (id < max) { |
| while (n > 0 && p) { |
| n -= IDR_BITS; |
| *paa++ = p; |
| p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); |
| } |
| |
| if (p) { |
| error = fn(id, (void *)p, data); |
| if (error) |
| break; |
| } |
| |
| id += 1 << n; |
| while (n < fls(id)) { |
| n += IDR_BITS; |
| p = *--paa; |
| } |
| } |
| |
| return error; |
| } |
| EXPORT_SYMBOL(idr_for_each); |
| |
| /** |
| * idr_get_next - lookup next object of id to given id. |
| * @idp: idr handle |
| * @id: pointer to lookup key |
| * |
| * Returns pointer to registered object with id, which is next number to |
| * given id. |
| */ |
| |
| void *idr_get_next(struct idr *idp, int *nextidp) |
| { |
| struct idr_layer *p, *pa[MAX_LEVEL]; |
| struct idr_layer **paa = &pa[0]; |
| int id = *nextidp; |
| int n, max; |
| |
| /* find first ent */ |
| n = idp->layers * IDR_BITS; |
| max = 1 << n; |
| p = rcu_dereference(idp->top); |
| if (!p) |
| return NULL; |
| |
| while (id < max) { |
| while (n > 0 && p) { |
| n -= IDR_BITS; |
| *paa++ = p; |
| p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); |
| } |
| |
| if (p) { |
| *nextidp = id; |
| return p; |
| } |
| |
| id += 1 << n; |
| while (n < fls(id)) { |
| n += IDR_BITS; |
| p = *--paa; |
| } |
| } |
| return NULL; |
| } |
| |
| |
| |
| /** |
| * idr_replace - replace pointer for given id |
| * @idp: idr handle |
| * @ptr: pointer you want associated with the id |
| * @id: lookup key |
| * |
| * Replace the pointer registered with an id and return the old value. |
| * A -ENOENT return indicates that @id was not found. |
| * A -EINVAL return indicates that @id was not within valid constraints. |
| * |
| * The caller must serialize with writers. |
| */ |
| void *idr_replace(struct idr *idp, void *ptr, int id) |
| { |
| int n; |
| struct idr_layer *p, *old_p; |
| |
| p = idp->top; |
| if (!p) |
| return ERR_PTR(-EINVAL); |
| |
| n = (p->layer+1) * IDR_BITS; |
| |
| id &= MAX_ID_MASK; |
| |
| if (id >= (1 << n)) |
| return ERR_PTR(-EINVAL); |
| |
| n -= IDR_BITS; |
| while ((n > 0) && p) { |
| p = p->ary[(id >> n) & IDR_MASK]; |
| n -= IDR_BITS; |
| } |
| |
| n = id & IDR_MASK; |
| if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) |
| return ERR_PTR(-ENOENT); |
| |
| old_p = p->ary[n]; |
| rcu_assign_pointer(p->ary[n], ptr); |
| |
| return old_p; |
| } |
| EXPORT_SYMBOL(idr_replace); |
| |
| |
| #endif |
| |
| |
| void idr_init_cache(void) |
| { |
| //idr_layer_cache = kmem_cache_create("idr_layer_cache", |
| // sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
| } |
| |
| /** |
| * idr_init - initialize idr handle |
| * @idp: idr handle |
| * |
| * This function is use to set up the handle (@idp) that you will pass |
| * to the rest of the functions. |
| */ |
| void idr_init(struct idr *idp) |
| { |
| memset(idp, 0, sizeof(struct idr)); |
| // spin_lock_init(&idp->lock); |
| } |
| EXPORT_SYMBOL(idr_init); |
| |
| #if 0 |
| |
| /* |
| * IDA - IDR based ID allocator |
| * |
| * this is id allocator without id -> pointer translation. Memory |
| * usage is much lower than full blown idr because each id only |
| * occupies a bit. ida uses a custom leaf node which contains |
| * IDA_BITMAP_BITS slots. |
| * |
| * 2007-04-25 written by Tejun Heo <htejun@gmail.com> |
| */ |
| |
| static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) |
| { |
| unsigned long flags; |
| |
| if (!ida->free_bitmap) { |
| spin_lock_irqsave(&ida->idr.lock, flags); |
| if (!ida->free_bitmap) { |
| ida->free_bitmap = bitmap; |
| bitmap = NULL; |
| } |
| spin_unlock_irqrestore(&ida->idr.lock, flags); |
| } |
| |
| kfree(bitmap); |
| } |
| |
| /** |
| * ida_pre_get - reserve resources for ida allocation |
| * @ida: ida handle |
| * @gfp_mask: memory allocation flag |
| * |
| * This function should be called prior to locking and calling the |
| * following function. It preallocates enough memory to satisfy the |
| * worst possible allocation. |
| * |
| * If the system is REALLY out of memory this function returns 0, |
| * otherwise 1. |
| */ |
| int ida_pre_get(struct ida *ida, gfp_t gfp_mask) |
| { |
| /* allocate idr_layers */ |
| if (!idr_pre_get(&ida->idr, gfp_mask)) |
| return 0; |
| |
| /* allocate free_bitmap */ |
| if (!ida->free_bitmap) { |
| struct ida_bitmap *bitmap; |
| |
| bitmap = kzalloc(sizeof(struct ida_bitmap), gfp_mask); |
| if (!bitmap) |
| return 0; |
| |
| free_bitmap(ida, bitmap); |
| } |
| |
| return 1; |
| } |
| EXPORT_SYMBOL(ida_pre_get); |
| |
| /** |
| * ida_get_new_above - allocate new ID above or equal to a start id |
| * @ida: ida handle |
| * @staring_id: id to start search at |
| * @p_id: pointer to the allocated handle |
| * |
| * Allocate new ID above or equal to @ida. It should be called with |
| * any required locks. |
| * |
| * If memory is required, it will return -EAGAIN, you should unlock |
| * and go back to the ida_pre_get() call. If the ida is full, it will |
| * return -ENOSPC. |
| * |
| * @p_id returns a value in the range @starting_id ... 0x7fffffff. |
| */ |
| int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) |
| { |
| struct idr_layer *pa[MAX_LEVEL]; |
| struct ida_bitmap *bitmap; |
| unsigned long flags; |
| int idr_id = starting_id / IDA_BITMAP_BITS; |
| int offset = starting_id % IDA_BITMAP_BITS; |
| int t, id; |
| |
| restart: |
| /* get vacant slot */ |
| t = idr_get_empty_slot(&ida->idr, idr_id, pa); |
| if (t < 0) |
| return _idr_rc_to_errno(t); |
| |
| if (t * IDA_BITMAP_BITS >= MAX_ID_BIT) |
| return -ENOSPC; |
| |
| if (t != idr_id) |
| offset = 0; |
| idr_id = t; |
| |
| /* if bitmap isn't there, create a new one */ |
| bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; |
| if (!bitmap) { |
| spin_lock_irqsave(&ida->idr.lock, flags); |
| bitmap = ida->free_bitmap; |
| ida->free_bitmap = NULL; |
| spin_unlock_irqrestore(&ida->idr.lock, flags); |
| |
| if (!bitmap) |
| return -EAGAIN; |
| |
| memset(bitmap, 0, sizeof(struct ida_bitmap)); |
| rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
| (void *)bitmap); |
| pa[0]->count++; |
| } |
| |
| /* lookup for empty slot */ |
| t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); |
| if (t == IDA_BITMAP_BITS) { |
| /* no empty slot after offset, continue to the next chunk */ |
| idr_id++; |
| offset = 0; |
| goto restart; |
| } |
| |
| id = idr_id * IDA_BITMAP_BITS + t; |
| if (id >= MAX_ID_BIT) |
| return -ENOSPC; |
| |
| __set_bit(t, bitmap->bitmap); |
| if (++bitmap->nr_busy == IDA_BITMAP_BITS) |
| idr_mark_full(pa, idr_id); |
| |
| *p_id = id; |
| |
| /* Each leaf node can handle nearly a thousand slots and the |
| * whole idea of ida is to have small memory foot print. |
| * Throw away extra resources one by one after each successful |
| * allocation. |
| */ |
| if (ida->idr.id_free_cnt || ida->free_bitmap) { |
| struct idr_layer *p = get_from_free_list(&ida->idr); |
| if (p) |
| kmem_cache_free(idr_layer_cache, p); |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(ida_get_new_above); |
| |
| /** |
| * ida_get_new - allocate new ID |
| * @ida: idr handle |
| * @p_id: pointer to the allocated handle |
| * |
| * Allocate new ID. It should be called with any required locks. |
| * |
| * If memory is required, it will return -EAGAIN, you should unlock |
| * and go back to the idr_pre_get() call. If the idr is full, it will |
| * return -ENOSPC. |
| * |
| * @id returns a value in the range 0 ... 0x7fffffff. |
| */ |
| int ida_get_new(struct ida *ida, int *p_id) |
| { |
| return ida_get_new_above(ida, 0, p_id); |
| } |
| EXPORT_SYMBOL(ida_get_new); |
| |
| /** |
| * ida_remove - remove the given ID |
| * @ida: ida handle |
| * @id: ID to free |
| */ |
| void ida_remove(struct ida *ida, int id) |
| { |
| struct idr_layer *p = ida->idr.top; |
| int shift = (ida->idr.layers - 1) * IDR_BITS; |
| int idr_id = id / IDA_BITMAP_BITS; |
| int offset = id % IDA_BITMAP_BITS; |
| int n; |
| struct ida_bitmap *bitmap; |
| |
| /* clear full bits while looking up the leaf idr_layer */ |
| while ((shift > 0) && p) { |
| n = (idr_id >> shift) & IDR_MASK; |
| __clear_bit(n, &p->bitmap); |
| p = p->ary[n]; |
| shift -= IDR_BITS; |
| } |
| |
| if (p == NULL) |
| goto err; |
| |
| n = idr_id & IDR_MASK; |
| __clear_bit(n, &p->bitmap); |
| |
| bitmap = (void *)p->ary[n]; |
| if (!test_bit(offset, bitmap->bitmap)) |
| goto err; |
| |
| /* update bitmap and remove it if empty */ |
| __clear_bit(offset, bitmap->bitmap); |
| if (--bitmap->nr_busy == 0) { |
| __set_bit(n, &p->bitmap); /* to please idr_remove() */ |
| idr_remove(&ida->idr, idr_id); |
| free_bitmap(ida, bitmap); |
| } |
| |
| return; |
| |
| err: |
| printk(KERN_WARNING |
| "ida_remove called for id=%d which is not allocated.\n", id); |
| } |
| EXPORT_SYMBOL(ida_remove); |
| |
| /** |
| * ida_destroy - release all cached layers within an ida tree |
| * ida: ida handle |
| */ |
| void ida_destroy(struct ida *ida) |
| { |
| idr_destroy(&ida->idr); |
| kfree(ida->free_bitmap); |
| } |
| EXPORT_SYMBOL(ida_destroy); |
| |
| /** |
| * ida_init - initialize ida handle |
| * @ida: ida handle |
| * |
| * This function is use to set up the handle (@ida) that you will pass |
| * to the rest of the functions. |
| */ |
| void ida_init(struct ida *ida) |
| { |
| memset(ida, 0, sizeof(struct ida)); |
| idr_init(&ida->idr); |
| |
| } |
| EXPORT_SYMBOL(ida_init); |
| |
| |
| #endif |