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Pull "trivial tree" updates from Jiri Kosina: "Usual pile from trivial tree everyone is so eagerly waiting for" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits) Remove MN10300_PROC_MN2WS0038 mei: fix comments treewide: Fix typos in Kconfig kprobes: update jprobe_example.c for do_fork() change Documentation: change "&" to "and" in Documentation/applying-patches.txt Documentation: remove obsolete pcmcia-cs from Changes Documentation: update links in Changes Documentation: Docbook: Fix generated DocBook/kernel-api.xml score: Remove GENERIC_HAS_IOMAP gpio: fix 'CONFIG_GPIO_IRQCHIP' comments tty: doc: Fix grammar in serial/tty dma-debug: modify check_for_stack output treewide: fix errors in printk genirq: fix reference in devm_request_threaded_irq comment treewide: fix synchronize_rcu() in comments checkstack.pl: port to AArch64 doc: queue-sysfs: minor fixes init/do_mounts: better syntax description MIPS: fix comment spelling powerpc/simpleboot: fix comment ...
1148 lines
28 KiB
C
1148 lines
28 KiB
C
/*
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* 2002-10-18 written by Jim Houston jim.houston@ccur.com
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* Copyright (C) 2002 by Concurrent Computer Corporation
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* Distributed under the GNU GPL license version 2.
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*
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* Modified by George Anzinger to reuse immediately and to use
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* find bit instructions. Also removed _irq on spinlocks.
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*
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* Modified by Nadia Derbey to make it RCU safe.
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*
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* Small id to pointer translation service.
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*
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* It uses a radix tree like structure as a sparse array indexed
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* by the id to obtain the pointer. The bitmap makes allocating
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* a new id quick.
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*
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* You call it to allocate an id (an int) an associate with that id a
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* pointer or what ever, we treat it as a (void *). You can pass this
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* id to a user for him to pass back at a later time. You then pass
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* that id to this code and it returns your pointer.
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*/
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#ifndef TEST // to test in user space...
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/export.h>
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#endif
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#include <linux/err.h>
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#include <linux/string.h>
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#include <linux/idr.h>
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#include <linux/spinlock.h>
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#include <linux/percpu.h>
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#include <linux/hardirq.h>
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#define MAX_IDR_SHIFT (sizeof(int) * 8 - 1)
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#define MAX_IDR_BIT (1U << MAX_IDR_SHIFT)
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/* Leave the possibility of an incomplete final layer */
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#define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS)
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/* Number of id_layer structs to leave in free list */
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#define MAX_IDR_FREE (MAX_IDR_LEVEL * 2)
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static struct kmem_cache *idr_layer_cache;
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static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head);
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static DEFINE_PER_CPU(int, idr_preload_cnt);
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static DEFINE_SPINLOCK(simple_ida_lock);
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/* the maximum ID which can be allocated given idr->layers */
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static int idr_max(int layers)
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{
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int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT);
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return (1 << bits) - 1;
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}
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/*
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* Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is
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* all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and
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* so on.
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*/
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static int idr_layer_prefix_mask(int layer)
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{
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return ~idr_max(layer + 1);
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}
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static struct idr_layer *get_from_free_list(struct idr *idp)
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{
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struct idr_layer *p;
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unsigned long flags;
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spin_lock_irqsave(&idp->lock, flags);
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if ((p = idp->id_free)) {
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idp->id_free = p->ary[0];
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idp->id_free_cnt--;
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p->ary[0] = NULL;
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}
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spin_unlock_irqrestore(&idp->lock, flags);
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return(p);
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}
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/**
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* idr_layer_alloc - allocate a new idr_layer
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* @gfp_mask: allocation mask
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* @layer_idr: optional idr to allocate from
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*
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* If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch
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* one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch
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* an idr_layer from @idr->id_free.
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*
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* @layer_idr is to maintain backward compatibility with the old alloc
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* interface - idr_pre_get() and idr_get_new*() - and will be removed
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* together with per-pool preload buffer.
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*/
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static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr)
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{
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struct idr_layer *new;
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/* this is the old path, bypass to get_from_free_list() */
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if (layer_idr)
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return get_from_free_list(layer_idr);
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/*
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* Try to allocate directly from kmem_cache. We want to try this
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* before preload buffer; otherwise, non-preloading idr_alloc()
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* users will end up taking advantage of preloading ones. As the
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* following is allowed to fail for preloaded cases, suppress
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* warning this time.
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*/
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new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN);
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if (new)
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return new;
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/*
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* Try to fetch one from the per-cpu preload buffer if in process
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* context. See idr_preload() for details.
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*/
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if (!in_interrupt()) {
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preempt_disable();
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new = __this_cpu_read(idr_preload_head);
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if (new) {
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__this_cpu_write(idr_preload_head, new->ary[0]);
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__this_cpu_dec(idr_preload_cnt);
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new->ary[0] = NULL;
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}
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preempt_enable();
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if (new)
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return new;
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}
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/*
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* Both failed. Try kmem_cache again w/o adding __GFP_NOWARN so
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* that memory allocation failure warning is printed as intended.
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*/
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return kmem_cache_zalloc(idr_layer_cache, gfp_mask);
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}
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static void idr_layer_rcu_free(struct rcu_head *head)
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{
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struct idr_layer *layer;
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layer = container_of(head, struct idr_layer, rcu_head);
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kmem_cache_free(idr_layer_cache, layer);
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}
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static inline void free_layer(struct idr *idr, struct idr_layer *p)
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{
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if (idr->hint == p)
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RCU_INIT_POINTER(idr->hint, NULL);
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call_rcu(&p->rcu_head, idr_layer_rcu_free);
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}
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/* only called when idp->lock is held */
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static void __move_to_free_list(struct idr *idp, struct idr_layer *p)
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{
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p->ary[0] = idp->id_free;
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idp->id_free = p;
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idp->id_free_cnt++;
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}
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static void move_to_free_list(struct idr *idp, struct idr_layer *p)
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{
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unsigned long flags;
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/*
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* Depends on the return element being zeroed.
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*/
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spin_lock_irqsave(&idp->lock, flags);
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__move_to_free_list(idp, p);
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spin_unlock_irqrestore(&idp->lock, flags);
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}
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static void idr_mark_full(struct idr_layer **pa, int id)
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{
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struct idr_layer *p = pa[0];
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int l = 0;
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__set_bit(id & IDR_MASK, p->bitmap);
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/*
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* If this layer is full mark the bit in the layer above to
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* show that this part of the radix tree is full. This may
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* complete the layer above and require walking up the radix
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* tree.
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*/
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while (bitmap_full(p->bitmap, IDR_SIZE)) {
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if (!(p = pa[++l]))
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break;
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id = id >> IDR_BITS;
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__set_bit((id & IDR_MASK), p->bitmap);
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}
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}
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static int __idr_pre_get(struct idr *idp, gfp_t gfp_mask)
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{
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while (idp->id_free_cnt < MAX_IDR_FREE) {
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struct idr_layer *new;
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new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
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if (new == NULL)
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return (0);
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move_to_free_list(idp, new);
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}
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return 1;
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}
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/**
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* sub_alloc - try to allocate an id without growing the tree depth
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* @idp: idr handle
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* @starting_id: id to start search at
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* @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer
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* @gfp_mask: allocation mask for idr_layer_alloc()
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* @layer_idr: optional idr passed to idr_layer_alloc()
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*
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* Allocate an id in range [@starting_id, INT_MAX] from @idp without
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* growing its depth. Returns
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*
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* the allocated id >= 0 if successful,
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* -EAGAIN if the tree needs to grow for allocation to succeed,
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* -ENOSPC if the id space is exhausted,
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* -ENOMEM if more idr_layers need to be allocated.
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*/
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static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa,
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gfp_t gfp_mask, struct idr *layer_idr)
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{
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int n, m, sh;
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struct idr_layer *p, *new;
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int l, id, oid;
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id = *starting_id;
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restart:
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p = idp->top;
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l = idp->layers;
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pa[l--] = NULL;
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while (1) {
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/*
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* We run around this while until we reach the leaf node...
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*/
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n = (id >> (IDR_BITS*l)) & IDR_MASK;
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m = find_next_zero_bit(p->bitmap, IDR_SIZE, n);
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if (m == IDR_SIZE) {
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/* no space available go back to previous layer. */
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l++;
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oid = id;
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id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
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/* if already at the top layer, we need to grow */
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if (id > idr_max(idp->layers)) {
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*starting_id = id;
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return -EAGAIN;
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}
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p = pa[l];
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BUG_ON(!p);
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/* If we need to go up one layer, continue the
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* loop; otherwise, restart from the top.
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*/
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sh = IDR_BITS * (l + 1);
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if (oid >> sh == id >> sh)
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continue;
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else
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goto restart;
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}
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if (m != n) {
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sh = IDR_BITS*l;
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id = ((id >> sh) ^ n ^ m) << sh;
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}
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if ((id >= MAX_IDR_BIT) || (id < 0))
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return -ENOSPC;
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if (l == 0)
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break;
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/*
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* Create the layer below if it is missing.
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*/
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if (!p->ary[m]) {
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new = idr_layer_alloc(gfp_mask, layer_idr);
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if (!new)
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return -ENOMEM;
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new->layer = l-1;
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new->prefix = id & idr_layer_prefix_mask(new->layer);
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rcu_assign_pointer(p->ary[m], new);
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p->count++;
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}
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pa[l--] = p;
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p = p->ary[m];
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}
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pa[l] = p;
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return id;
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}
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static int idr_get_empty_slot(struct idr *idp, int starting_id,
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struct idr_layer **pa, gfp_t gfp_mask,
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struct idr *layer_idr)
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{
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struct idr_layer *p, *new;
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int layers, v, id;
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unsigned long flags;
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id = starting_id;
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build_up:
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p = idp->top;
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layers = idp->layers;
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if (unlikely(!p)) {
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if (!(p = idr_layer_alloc(gfp_mask, layer_idr)))
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return -ENOMEM;
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p->layer = 0;
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layers = 1;
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}
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/*
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* Add a new layer to the top of the tree if the requested
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* id is larger than the currently allocated space.
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*/
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while (id > idr_max(layers)) {
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layers++;
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if (!p->count) {
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/* special case: if the tree is currently empty,
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* then we grow the tree by moving the top node
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* upwards.
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*/
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p->layer++;
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WARN_ON_ONCE(p->prefix);
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continue;
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}
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if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) {
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/*
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* The allocation failed. If we built part of
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* the structure tear it down.
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*/
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spin_lock_irqsave(&idp->lock, flags);
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for (new = p; p && p != idp->top; new = p) {
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p = p->ary[0];
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new->ary[0] = NULL;
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new->count = 0;
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bitmap_clear(new->bitmap, 0, IDR_SIZE);
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__move_to_free_list(idp, new);
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}
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spin_unlock_irqrestore(&idp->lock, flags);
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return -ENOMEM;
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}
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new->ary[0] = p;
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new->count = 1;
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new->layer = layers-1;
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new->prefix = id & idr_layer_prefix_mask(new->layer);
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if (bitmap_full(p->bitmap, IDR_SIZE))
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__set_bit(0, new->bitmap);
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p = new;
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}
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rcu_assign_pointer(idp->top, p);
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idp->layers = layers;
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v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr);
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if (v == -EAGAIN)
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goto build_up;
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return(v);
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}
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/*
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* @id and @pa are from a successful allocation from idr_get_empty_slot().
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* Install the user pointer @ptr and mark the slot full.
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*/
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static void idr_fill_slot(struct idr *idr, void *ptr, int id,
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struct idr_layer **pa)
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{
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/* update hint used for lookup, cleared from free_layer() */
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rcu_assign_pointer(idr->hint, pa[0]);
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rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr);
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pa[0]->count++;
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idr_mark_full(pa, id);
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}
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/**
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* idr_preload - preload for idr_alloc()
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* @gfp_mask: allocation mask to use for preloading
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*
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* Preload per-cpu layer buffer for idr_alloc(). Can only be used from
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* process context and each idr_preload() invocation should be matched with
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* idr_preload_end(). Note that preemption is disabled while preloaded.
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*
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* The first idr_alloc() in the preloaded section can be treated as if it
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* were invoked with @gfp_mask used for preloading. This allows using more
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* permissive allocation masks for idrs protected by spinlocks.
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*
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* For example, if idr_alloc() below fails, the failure can be treated as
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* if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT.
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*
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* idr_preload(GFP_KERNEL);
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* spin_lock(lock);
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*
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* id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT);
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*
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* spin_unlock(lock);
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* idr_preload_end();
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* if (id < 0)
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* error;
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*/
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void idr_preload(gfp_t gfp_mask)
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{
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/*
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* Consuming preload buffer from non-process context breaks preload
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* allocation guarantee. Disallow usage from those contexts.
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*/
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WARN_ON_ONCE(in_interrupt());
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might_sleep_if(gfp_mask & __GFP_WAIT);
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preempt_disable();
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|
|
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/*
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* idr_alloc() is likely to succeed w/o full idr_layer buffer and
|
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* return value from idr_alloc() needs to be checked for failure
|
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* anyway. Silently give up if allocation fails. The caller can
|
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* treat failures from idr_alloc() as if idr_alloc() were called
|
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* with @gfp_mask which should be enough.
|
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*/
|
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while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) {
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struct idr_layer *new;
|
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|
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preempt_enable();
|
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new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
|
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preempt_disable();
|
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if (!new)
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break;
|
|
|
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/* link the new one to per-cpu preload list */
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new->ary[0] = __this_cpu_read(idr_preload_head);
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__this_cpu_write(idr_preload_head, new);
|
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__this_cpu_inc(idr_preload_cnt);
|
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}
|
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}
|
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EXPORT_SYMBOL(idr_preload);
|
|
|
|
/**
|
|
* idr_alloc - allocate new idr entry
|
|
* @idr: the (initialized) idr
|
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* @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(gfp_mask & __GFP_WAIT);
|
|
|
|
/* sanity checks */
|
|
if (WARN_ON_ONCE(start < 0))
|
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return -EINVAL;
|
|
if (unlikely(max < start))
|
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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;
|
|
}
|
|
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;
|
|
}
|
|
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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
}
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
}
|
|
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);
|
|
}
|
|
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;
|
|
}
|
|
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 p;
|
|
}
|
|
|
|
/*
|
|
* Proceed to the next layer at the current level. Unlike
|
|
* idr_for_each(), @id isn't guaranteed to be aligned to
|
|
* layer boundary at this point and adding 1 << n may
|
|
* incorrectly skip IDs. Make sure we jump to the
|
|
* beginning of the next layer using round_up().
|
|
*/
|
|
id = round_up(id + 1, 1 << n);
|
|
while (n < fls(id)) {
|
|
n += IDR_BITS;
|
|
--paa;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(idr_get_next);
|
|
|
|
|
|
/**
|
|
* 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;
|
|
|
|
if (id < 0)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
p = idp->top;
|
|
if (!p)
|
|
return ERR_PTR(-ENOENT);
|
|
|
|
if (id > idr_max(p->layer + 1))
|
|
return ERR_PTR(-ENOENT);
|
|
|
|
n = p->layer * 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);
|
|
|
|
void __init 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);
|
|
|
|
static int idr_has_entry(int id, void *p, void *data)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
bool idr_is_empty(struct idr *idp)
|
|
{
|
|
return !idr_for_each(idp, idr_has_entry, NULL);
|
|
}
|
|
EXPORT_SYMBOL(idr_is_empty);
|
|
|
|
/**
|
|
* DOC: IDA description
|
|
* 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 = kmalloc(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
|
|
* @starting_id: id to start search at
|
|
* @p_id: pointer to the allocated handle
|
|
*
|
|
* Allocate new ID above or equal to @starting_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 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_IDR_LEVEL + 1];
|
|
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, 0, &ida->idr);
|
|
if (t < 0)
|
|
return t == -ENOMEM ? -EAGAIN : t;
|
|
|
|
if (t * IDA_BITMAP_BITS >= MAX_IDR_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_IDR_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_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;
|
|
|
|
if (idr_id > idr_max(ida->idr.layers))
|
|
goto err;
|
|
|
|
/* 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 (!bitmap || !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:
|
|
WARN(1, "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_simple_get - get a new id.
|
|
* @ida: the (initialized) ida.
|
|
* @start: the minimum id (inclusive, < 0x8000000)
|
|
* @end: the maximum id (exclusive, < 0x8000000 or 0)
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* Allocates an id in the range start <= id < end, or returns -ENOSPC.
|
|
* On memory allocation failure, returns -ENOMEM.
|
|
*
|
|
* Use ida_simple_remove() to get rid of an id.
|
|
*/
|
|
int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
|
|
gfp_t gfp_mask)
|
|
{
|
|
int ret, id;
|
|
unsigned int max;
|
|
unsigned long flags;
|
|
|
|
BUG_ON((int)start < 0);
|
|
BUG_ON((int)end < 0);
|
|
|
|
if (end == 0)
|
|
max = 0x80000000;
|
|
else {
|
|
BUG_ON(end < start);
|
|
max = end - 1;
|
|
}
|
|
|
|
again:
|
|
if (!ida_pre_get(ida, gfp_mask))
|
|
return -ENOMEM;
|
|
|
|
spin_lock_irqsave(&simple_ida_lock, flags);
|
|
ret = ida_get_new_above(ida, start, &id);
|
|
if (!ret) {
|
|
if (id > max) {
|
|
ida_remove(ida, id);
|
|
ret = -ENOSPC;
|
|
} else {
|
|
ret = id;
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&simple_ida_lock, flags);
|
|
|
|
if (unlikely(ret == -EAGAIN))
|
|
goto again;
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(ida_simple_get);
|
|
|
|
/**
|
|
* ida_simple_remove - remove an allocated id.
|
|
* @ida: the (initialized) ida.
|
|
* @id: the id returned by ida_simple_get.
|
|
*/
|
|
void ida_simple_remove(struct ida *ida, unsigned int id)
|
|
{
|
|
unsigned long flags;
|
|
|
|
BUG_ON((int)id < 0);
|
|
spin_lock_irqsave(&simple_ida_lock, flags);
|
|
ida_remove(ida, id);
|
|
spin_unlock_irqrestore(&simple_ida_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(ida_simple_remove);
|
|
|
|
/**
|
|
* 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);
|