cregit-Linux how code gets into the kernel

Release 4.8 lib/idr.c

Directory: lib
/*
 * 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.
 */

#ifndef TEST                        // to test in user space...
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/export.h>
#endif
#include <linux/err.h>
#include <linux/string.h>
#include <linux/idr.h>
#include <linux/spinlock.h>
#include <linux/percpu.h>


#define MAX_IDR_SHIFT		(sizeof(int) * 8 - 1)

#define MAX_IDR_BIT		(1U << MAX_IDR_SHIFT)

/* Leave the possibility of an incomplete final layer */

#define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS)

/* Number of id_layer structs to leave in free list */

#define MAX_IDR_FREE (MAX_IDR_LEVEL * 2)


static struct kmem_cache *idr_layer_cache;
static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head);
static DEFINE_PER_CPU(int, idr_preload_cnt);
static DEFINE_SPINLOCK(simple_ida_lock);

/* the maximum ID which can be allocated given idr->layers */

static int idr_max(int layers) { int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); return (1 << bits) - 1; }

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tejun heotejun heo32100.00%1100.00%
Total32100.00%1100.00%

/* * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and * so on. */
static int idr_layer_prefix_mask(int layer) { return ~idr_max(layer + 1); }

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tejun heotejun heo18100.00%1100.00%
Total18100.00%1100.00%


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); }

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PersonTokensPropCommitsCommitProp
george anzingergeorge anzinger7083.33%116.67%
roland dreierroland dreier1011.90%116.67%
linus torvaldslinus torvalds11.19%116.67%
ulrich drepperulrich drepper11.19%116.67%
li shaohuali shaohua11.19%116.67%
nadia derbeynadia derbey11.19%116.67%
Total84100.00%6100.00%

/** * idr_layer_alloc - allocate a new idr_layer * @gfp_mask: allocation mask * @layer_idr: optional idr to allocate from * * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch * an idr_layer from @idr->id_free. * * @layer_idr is to maintain backward compatibility with the old alloc * interface - idr_pre_get() and idr_get_new*() - and will be removed * together with per-pool preload buffer. */
static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) { struct idr_layer *new; /* this is the old path, bypass to get_from_free_list() */ if (layer_idr) return get_from_free_list(layer_idr); /* * Try to allocate directly from kmem_cache. We want to try this * before preload buffer; otherwise, non-preloading idr_alloc() * users will end up taking advantage of preloading ones. As the * following is allowed to fail for preloaded cases, suppress * warning this time. */ new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN); if (new) return new; /* * Try to fetch one from the per-cpu preload buffer if in process * context. See idr_preload() for details. */ if (!in_interrupt()) { preempt_disable(); new = __this_cpu_read(idr_preload_head); if (new) { __this_cpu_write(idr_preload_head, new->ary[0]); __this_cpu_dec(idr_preload_cnt); new->ary[0] = NULL; } preempt_enable(); if (new) return new; } /* * Both failed. Try kmem_cache again w/o adding __GFP_NOWARN so * that memory allocation failure warning is printed as intended. */ return kmem_cache_zalloc(idr_layer_cache, gfp_mask); }

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tejun heotejun heo121100.00%2100.00%
Total121100.00%2100.00%


static void idr_layer_rcu_free(struct rcu_head *head) { struct idr_layer *layer; layer = container_of(head, struct idr_layer, rcu_head); kmem_cache_free(idr_layer_cache, layer); }

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nadia derbeynadia derbey35100.00%1100.00%
Total35100.00%1100.00%


static inline void free_layer(struct idr *idr, struct idr_layer *p) { if (idr->hint == p) RCU_INIT_POINTER(idr->hint, NULL); call_rcu(&p->rcu_head, idr_layer_rcu_free); }

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tejun heotejun heo2250.00%150.00%
nadia derbeynadia derbey2250.00%150.00%
Total44100.00%2100.00%

/* 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++; }

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PersonTokensPropCommitsCommitProp
george anzingergeorge anzinger3694.74%133.33%
nadia derbeynadia derbey12.63%133.33%
sonny raosonny rao12.63%133.33%
Total38100.00%3100.00%


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); }

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PersonTokensPropCommitsCommitProp
sonny raosonny rao2858.33%125.00%
roland dreierroland dreier1020.83%125.00%
george anzingergeorge anzinger816.67%125.00%
nadia derbeynadia derbey24.17%125.00%
Total48100.00%4100.00%


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 (bitmap_full(p->bitmap, IDR_SIZE)) { if (!(p = pa[++l])) break; id = id >> IDR_BITS; __set_bit((id & IDR_MASK), p->bitmap); } }

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tejun heotejun heo88100.00%2100.00%
Total88100.00%2100.00%


static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) { while (idp->id_free_cnt < MAX_IDR_FREE) { struct idr_layer *new; new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); if (new == NULL) return (0); move_to_free_list(idp, new); } return 1; }

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PersonTokensPropCommitsCommitProp
george anzingergeorge anzinger5084.75%112.50%
andrew mortonandrew morton46.78%225.00%
nadia derbeynadia derbey11.69%112.50%
al viroal viro11.69%112.50%
stephen hemmingerstephen hemminger11.69%112.50%
fengguang wufengguang wu11.69%112.50%
tejun heotejun heo11.69%112.50%
Total59100.00%8100.00%

/** * sub_alloc - try to allocate an id without growing the tree depth * @idp: idr handle * @starting_id: id to start search at * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer * @gfp_mask: allocation mask for idr_layer_alloc() * @layer_idr: optional idr passed to idr_layer_alloc() * * Allocate an id in range [@starting_id, INT_MAX] from @idp without * growing its depth. Returns * * the allocated id >= 0 if successful, * -EAGAIN if the tree needs to grow for allocation to succeed, * -ENOSPC if the id space is exhausted, * -ENOMEM if more idr_layers need to be allocated. */
static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, gfp_t gfp_mask, struct idr *layer_idr) { int n, m, sh; struct idr_layer *p, *new; int l, id, oid; 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; m = find_next_zero_bit(p->bitmap, 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 (id > idr_max(idp->layers)) { *starting_id = id; return -EAGAIN; } p = pa[l]; BUG_ON(!p); /* 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_IDR_BIT) || (id < 0)) return -ENOSPC; if (l == 0) break; /* * Create the layer below if it is missing. */ if (!p->ary[m]) { new = idr_layer_alloc(gfp_mask, layer_idr); if (!new) return -ENOMEM; new->layer = l-1; new->prefix = id & idr_layer_prefix_mask(new->layer); rcu_assign_pointer(p->ary[m], new); p->count++; } pa[l--] = p; p = p->ary[m]; } pa[l] = p; return id; }

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PersonTokensPropCommitsCommitProp
andrew mortonandrew morton15642.98%212.50%
tejun heotejun heo9024.79%743.75%
george anzingergeorge anzinger8723.97%16.25%
nadia derbeynadia derbey92.48%212.50%
corey minyardcorey minyard82.20%16.25%
manfred spraulmanfred spraul82.20%16.25%
lai jiangshanlai jiangshan41.10%16.25%
fengguang wufengguang wu10.28%16.25%
Total363100.00%16100.00%


static int idr_get_empty_slot(struct idr *idp, int starting_id, struct idr_layer **pa, gfp_t gfp_mask, struct idr *layer_idr) { 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 = idr_layer_alloc(gfp_mask, layer_idr))) return -ENOMEM; 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 (id > idr_max(layers)) { 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++; WARN_ON_ONCE(p->prefix); continue; } if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { /* * 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->count = 0; bitmap_clear(new->bitmap, 0, IDR_SIZE); __move_to_free_list(idp, new); } spin_unlock_irqrestore(&idp->lock, flags); return -ENOMEM; } new->ary[0] = p; new->count = 1; new->layer = layers-1; new->prefix = id & idr_layer_prefix_mask(new->layer); if (bitmap_full(p->bitmap, IDR_SIZE)) __set_bit(0, new->bitmap); p = new; } rcu_assign_pointer(idp->top, p); idp->layers = layers; v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); if (v == -EAGAIN) goto build_up; return(v); }

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PersonTokensPropCommitsCommitProp
andrew mortonandrew morton15042.86%211.76%
george anzingergeorge anzinger7521.43%15.88%
tejun heotejun heo7220.57%635.29%
manfred spraulmanfred spraul226.29%211.76%
sonny raosonny rao144.00%15.88%
roland dreierroland dreier102.86%15.88%
nadia derbeynadia derbey51.43%211.76%
linus torvaldslinus torvalds10.29%15.88%
corey minyardcorey minyard10.29%15.88%
Total350100.00%17100.00%

/* * @id and @pa are from a successful allocation from idr_get_empty_slot(). * Install the user pointer @ptr and mark the slot full. */
static void idr_fill_slot(struct idr *idr, void *ptr, int id, struct idr_layer **pa) { /* update hint used for lookup, cleared from free_layer() */ rcu_assign_pointer(idr->hint, pa[0]); rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); pa[0]->count++; idr_mark_full(pa, id); }

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tejun heotejun heo7094.59%375.00%
nadia derbeynadia derbey45.41%125.00%
Total74100.00%4100.00%

/** * idr_preload - preload for idr_alloc() * @gfp_mask: allocation mask to use for preloading * * Preload per-cpu layer buffer for idr_alloc(). Can only be used from * process context and each idr_preload() invocation should be matched with * idr_preload_end(). Note that preemption is disabled while preloaded. * * The first idr_alloc() in the preloaded section can be treated as if it * were invoked with @gfp_mask used for preloading. This allows using more * permissive allocation masks for idrs protected by spinlocks. * * For example, if idr_alloc() below fails, the failure can be treated as * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. * * idr_preload(GFP_KERNEL); * spin_lock(lock); * * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); * * spin_unlock(lock); * idr_preload_end(); * if (id < 0) * error; */
void idr_preload(gfp_t gfp_mask) { /* * Consuming preload buffer from non-process context breaks preload * allocation guarantee. Disallow usage from those contexts. */ WARN_ON_ONCE(in_interrupt()); might_sleep_if(gfpflags_allow_blocking(gfp_mask)); preempt_disable(); /* * idr_alloc() is likely to succeed w/o full idr_layer buffer and * return value from idr_alloc() needs to be checked for failure * anyway. Silently give up if allocation fails. The caller can * treat failures from idr_alloc() as if idr_alloc() were called * with @gfp_mask which should be enough. */ while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { struct idr_layer *new; preempt_enable(); new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); preempt_disable(); if (!new) break; /* link the new one to per-cpu preload list */ new->ary[0] = __this_cpu_read(idr_preload_head); __this_cpu_write(idr_preload_head, new); __this_cpu_inc(idr_preload_cnt); } }

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tejun heotejun heo8696.63%150.00%
mel gormanmel gorman33.37%150.00%
Total89100.00%2100.00%

EXPORT_SYMBOL(idr_preload); /** * idr_alloc - allocate new idr entry * @idr: the (initialized) idr * @ptr: pointer to be associated with the new id * @start: the minimum id (inclusive) * @end: the maximum id (exclusive, <= 0 for max) * @gfp_mask: memory allocation flags * * Allocate an id in [start, end) and associate it with @ptr. If no ID is * available in the specified range, returns -ENOSPC. On memory allocation * failure, returns -ENOMEM. * * Note that @end is treated as max when <= 0. This is to always allow * using @start + N as @end as long as N is inside integer range. * * The user is responsible for exclusively synchronizing all operations * which may modify @idr. However, read-only accesses such as idr_find() * or iteration can be performed under RCU read lock provided the user * destroys @ptr in RCU-safe way after removal from idr. */
int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) { int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ struct idr_layer *pa[MAX_IDR_LEVEL + 1]; int id; might_sleep_if(gfpflags_allow_blocking(gfp_mask)); /* sanity checks */ if (WARN_ON_ONCE(start < 0)) return -EINVAL; if (unlikely(max < start)) return -ENOSPC; /* allocate id */ id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); if (unlikely(id < 0)) return id; if (unlikely(id > max)) return -ENOSPC; idr_fill_slot(idr, ptr, id, pa); return id; }

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tejun heotejun heo13797.86%375.00%
mel gormanmel gorman32.14%125.00%
Total140100.00%4100.00%

EXPORT_SYMBOL_GPL(idr_alloc); /** * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion * @idr: the (initialized) idr * @ptr: pointer to be associated with the new id * @start: the minimum id (inclusive) * @end: the maximum id (exclusive, <= 0 for max) * @gfp_mask: memory allocation flags * * Essentially the same as idr_alloc, but prefers to allocate progressively * higher ids if it can. If the "cur" counter wraps, then it will start again * at the "start" end of the range and allocate one that has already been used. */
int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) { int id; id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask); if (id == -ENOSPC) id = idr_alloc(idr, ptr, start, end, gfp_mask); if (likely(id >= 0)) idr->cur = id + 1; return id; }

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jeff laytonjeff layton90100.00%1100.00%
Total90100.00%1100.00%

EXPORT_SYMBOL(idr_alloc_cyclic);
static void idr_remove_warning(int id) { WARN(1, "idr_remove called for id=%d which is not allocated.\n", id); }

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jim houstonjim houston1583.33%150.00%
jean delvarejean delvare316.67%150.00%
Total18100.00%2100.00%


static void sub_remove(struct idr *idp, int shift, int id) { struct idr_layer *p = idp->top; struct idr_layer **pa[MAX_IDR_LEVEL + 1]; 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_INIT_POINTER(p->ary[n], NULL); to_free = NULL; while(*paa && ! --((**paa)->count)){ if (to_free) free_layer(idp, to_free); to_free = **paa; **paa-- = NULL; } if (!*paa) idp->layers = 0; if (to_free) free_layer(idp, to_free); } else idr_remove_warning(id); }

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george anzingergeorge anzinger18473.31%112.50%
nadia derbeynadia derbey3011.95%112.50%
jim houstonjim houston2710.76%112.50%
tejun heotejun heo62.39%225.00%
andrew mortonandrew morton20.80%112.50%
monam agarwalmonam agarwal10.40%112.50%
fengguang wufengguang wu10.40%112.50%
Total251100.00%8100.00%

/** * idr_remove - remove the given id and free its slot * @idp: idr handle * @id: unique key */
void idr_remove(struct idr *idp, int id) { struct idr_layer *p; struct idr_layer *to_free; if (id < 0) return; if (id > idr_max(idp->layers)) { idr_remove_warning(id); return; } 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->count = 0; bitmap_clear(to_free->bitmap, 0, IDR_SIZE); free_layer(idp, to_free); } }

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PersonTokensPropCommitsCommitProp
george anzingergeorge anzinger9058.06%114.29%
nadia derbeynadia derbey2717.42%114.29%
lai jiangshanlai jiangshan1912.26%114.29%
tejun heotejun heo1811.61%342.86%
corey minyardcorey minyard10.65%114.29%
Total155100.00%7100.00%

EXPORT_SYMBOL(idr_remove);
static void __idr_remove_all(struct idr *idp) { int n, id, max; int bt_mask; struct idr_layer *p; struct idr_layer *pa[MAX_IDR_LEVEL + 1]; struct idr_layer **paa = &pa[0]; n = idp->layers * IDR_BITS; *paa = idp->top; RCU_INIT_POINTER(idp->top, NULL); max = idr_max(idp->layers); id = 0; while (id >= 0 && id <= max) { p = *paa; while (n > IDR_BITS && p) { n -= IDR_BITS; p = p->ary[(id >> n) & IDR_MASK]; *++paa = p; } bt_mask = id; id += 1 << n; /* Get the highest bit that the above add changed from 0->1. */ while (n < fls(id ^ bt_mask)) { if (*paa) free_layer(idp, *paa); n += IDR_BITS; --paa; } } idp->layers = 0; }

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kristian hogsbergkristian hogsberg13270.59%19.09%
andrey ryabininandrey ryabinin179.09%19.09%
tejun heotejun heo168.56%327.27%
imre deakimre deak105.35%19.09%
paul e. mckenneypaul e. mckenney84.28%19.09%
stephen hemmingerstephen hemminger10.53%19.09%
fengguang wufengguang wu10.53%19.09%
monam agarwalmonam agarwal10.53%19.09%
nadia derbeynadia derbey10.53%19.09%
Total187100.00%11100.00%

/** * idr_destroy - release all cached layers within an idr tree * @idp: idr handle * * Free all id mappings and all idp_layers. After this function, @idp is * completely unused and can be freed / recycled. The caller is * responsible for ensuring that no one else accesses @idp during or after * idr_destroy(). * * A typical clean-up sequence for objects stored in an idr tree will use * idr_for_each() to free all objects, if necessary, then idr_destroy() to * free up the id mappings and cached idr_layers. */
void idr_destroy(struct idr *idp) { __idr_remove_all(idp); while (idp->id_free_cnt) { struct idr_layer *p = get_from_free_list(idp); kmem_cache_free(idr_layer_cache, p); } }

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andrew mortonandrew morton3485.00%125.00%
tejun heotejun heo512.50%250.00%
nadia derbeynadia derbey12.50%125.00%
Total40100.00%4100.00%

EXPORT_SYMBOL(idr_destroy);
void *idr_find_slowpath(struct idr *idp, int id) { int n; struct idr_layer *p; if (id < 0) return NULL; p = rcu_dereference_raw(idp->top); if (!p) return NULL; n = (p->layer+1) * IDR_BITS; if (id > idr_max(p->layer + 1)) return NULL; BUG_ON(n == 0); while (n > 0 && p) { n -= IDR_BITS; BUG_ON(n != p->layer*IDR_BITS); p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); } return((void *)p); }

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george anzingergeorge anzinger6548.15%112.50%
manfred spraulmanfred spraul3828.15%112.50%
tejun heotejun heo1813.33%337.50%
christoph hellwigchristoph hellwig85.93%112.50%
nadia derbeynadia derbey42.96%112.50%
paul e. mckenneypaul e. mckenney21.48%112.50%
Total135100.00%8100.00%

EXPORT_SYMBOL(idr_find_slowpath); /** * 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_IDR_LEVEL + 1]; struct idr_layer **paa = &pa[0]; n = idp->layers * IDR_BITS; *paa = rcu_dereference_raw(idp->top); max = idr_max(idp->layers); id = 0; while (id >= 0 && id <= max) { p = *paa; while (n > 0 && p) { n -= IDR_BITS; p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); *++paa = p; } if (p) { error = fn(id, (void *)p, data); if (error) break; } id += 1 << n; while (n < fls(id)) { n += IDR_BITS; --paa; } } return error; }

Contributors

PersonTokensPropCommitsCommitProp
kristian hogsbergkristian hogsberg17684.21%116.67%
andrey ryabininandrey ryabinin136.22%116.67%
tejun heotejun heo136.22%116.67%
nadia derbeynadia derbey41.91%116.67%
paul e. mckenneypaul e. mckenney20.96%116.67%
fengguang wufengguang wu10.48%116.67%
Total209100.00%6100.00%

EXPORT_SYMBOL(idr_for_each); /** * idr_get_next - lookup next object of id to given id. * @idp: idr handle * @nextidp: pointer to lookup key * * Returns pointer to registered object with id, which is next number to * given id. After being looked up, *@nextidp will be updated for the next * iteration. * * This function can be called under rcu_read_lock(), given that the leaf * pointers lifetimes are correctly managed. */
void *idr_get_next(struct idr *idp, int *nextidp) { struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; struct idr_layer **paa = &pa[0]; int id = *nextidp; int n, max; /* find first ent */ p = *paa = rcu_dereference_raw(idp->top); if (!p) return NULL; n = (p->layer + 1) * IDR_BITS; max = idr_max(p->layer + 1); while (id >= 0 && id <= max) { p = *paa; while (n > 0 && p) { n -= IDR_BITS; p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); *++paa = p; } if (p) { *nextidp = id; return