[U-Boot-Users] [Patch 2/9]U-boot-V2:ID: Introduce idr
Menon, Nishanth
x0nishan at ti.com
Thu Jun 19 17:11:27 CEST 2008
Introduce selected ID table translation functions
from Linux kernel.
Signed-off-by: Nishanth Menon <x0nishan at ti.com>
---
include/linux/idr.h | 91 ++++++++++++
lib/Makefile | 1
lib/idr.c | 392 ++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 484 insertions(+)
Index: u-boot-v2.git/include/linux/idr.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ u-boot-v2.git/include/linux/idr.h 2008-06-19 08:41:21.000000000 -0500
@@ -0,0 +1,91 @@
+/**
+ * @file
+ * @brief Small id to pointer translation service avoiding fixed sized
+ * tables.
+ *
+ * FileName: include/linux/idr.h
+ *
+ */
+/* Originally from Linux kernel. Ported to U-boot-v2.
+ * (C) Copyright 2008
+ * Texas Instruments, <www.ti.com>
+ * Nishanth Menon <x0nishan at ti.com>
+ */
+/*
+ *
+ * 2002-10-18 written by Jim Houston jim.houston at ccur.com
+ * Copyright (C) 2002 by Concurrent Computer Corporation
+ * Distributed under the GNU GPL license version 2.
+ */
+
+#ifndef __IDR_H__
+#define __IDR_H__
+
+#include <linux/types.h>
+#include <linux/bitops.h>
+#include <init.h>
+
+#if BITS_PER_LONG == 32
+# define IDR_BITS 5
+# define IDR_FULL 0xfffffffful
+/** We can only use two of the bits in the top level because there is
+ only one possible bit in the top level (5 bits * 7 levels = 35
+ bits, but you only use 31 bits in the id). */
+# define TOP_LEVEL_FULL (IDR_FULL >> 30)
+#elif BITS_PER_LONG == 64
+# define IDR_BITS 6
+# define IDR_FULL 0xfffffffffffffffful
+/** We can only use two of the bits in the top level because there is
+ only one possible bit in the top level (6 bits * 6 levels = 36
+ bits, but you only use 31 bits in the id). */
+# define TOP_LEVEL_FULL (IDR_FULL >> 62)
+#else
+# error "BITS_PER_LONG is not 32 or 64"
+#endif
+
+#define IDR_SIZE (1 << IDR_BITS)
+#define IDR_MASK ((1 << IDR_BITS)-1)
+
+#define MAX_ID_SHIFT (sizeof(int)*8 - 1)
+#define MAX_ID_BIT (1U << MAX_ID_SHIFT)
+#define MAX_ID_MASK (MAX_ID_BIT - 1)
+
+/** Leave the possibility of an incomplete final layer */
+#define MAX_LEVEL ((MAX_ID_SHIFT + IDR_BITS - 1) / IDR_BITS)
+
+/** Number of id_layer structs to leave in free list */
+#define IDR_FREE_MAX (MAX_LEVEL + MAX_LEVEL)
+
+struct idr_layer {
+ unsigned long bitmap; /** A zero bit means "space here" */
+ struct idr_layer *ary[1 << IDR_BITS];
+ int count; /** When zero, we can release it */
+};
+
+struct idr {
+ struct idr_layer *top;
+ struct idr_layer *id_free;
+ int layers;
+ int id_free_cnt;
+};
+
+#define IDR_INIT(name) \
+{ \
+ .top = NULL, \
+ .id_free = NULL, \
+ .layers = 0, \
+ .id_free_cnt = 0, \
+}
+#define DEFINE_IDR(name) struct idr name = IDR_INIT(name)
+
+/**
+ * This is what we export.
+ */
+
+void *idr_find(struct idr *idp, int id);
+int idr_pre_get(struct idr *idp);
+int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id);
+void idr_remove(struct idr *idp, int id);
+void idr_init(struct idr *idp);
+
+#endif /* __IDR_H__ */
Index: u-boot-v2.git/lib/idr.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ u-boot-v2.git/lib/idr.c 2008-06-19 08:42:27.000000000 -0500
@@ -0,0 +1,392 @@
+/**
+ * @file
+ * @brief Small id to pointer translation service.
+ *
+ * FileName: lib/idr.c
+ *
+ * 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.
+ */
+/* Originally from Linux kernel. Ported to U-boot-v2.
+ * (C) Copyright 2008
+ * Texas Instruments, <www.ti.com>
+ * Nishanth Menon <x0nishan at ti.com>
+ */
+/*
+ * 2002-10-18 written by Jim Houston jim.houston at 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.
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <string.h>
+#include <init.h>
+#include <malloc.h>
+#include <linux/bitops.h>
+#include <linux/idr.h>
+
+static void idr_remove_warning(int id)
+{
+ printf("idr_remove called for id=%d which is not allocated.\n", id);
+ hang();
+}
+
+static struct idr_layer *alloc_layer(struct idr *idp)
+{
+ struct idr_layer *p;
+ p = idp->id_free;
+ if (p) {
+ idp->id_free = p->ary[0];
+ idp->id_free_cnt--;
+ p->ary[0] = NULL;
+ }
+ return p;
+}
+
+/* only called when idp->lock is held */
+static void __free_layer(struct idr *idp, struct idr_layer *p)
+{
+ p->ary[0] = idp->id_free;
+ idp->id_free = p;
+ idp->id_free_cnt++;
+}
+
+static void free_layer(struct idr *idp, struct idr_layer *p)
+{
+ /*
+ * Depends on the return element being zeroed.
+ */
+ __free_layer(idp, p);
+}
+
+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 */
+ p = pa[l];
+ if (!p) {
+ *starting_id = id;
+ return -2;
+ }
+
+ /* 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 -3;
+ if (l == 0)
+ break;
+ /*
+ * Create the layer below if it is missing.
+ */
+ if (!p->ary[m]) {
+ new = alloc_layer(idp);
+ if (!new)
+ return -1;
+ p->ary[m] = new;
+ p->count++;
+ }
+ pa[l--] = p;
+ p = p->ary[m];
+ }
+
+ pa[l] = p;
+ return id;
+}
+
+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];
+ 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 (p != NULL && test_bit(n, &p->bitmap)) {
+ __clear_bit(n, &p->bitmap);
+ p->ary[n] = NULL;
+ while (*paa && !--((**paa)->count)) {
+ free_layer(idp, **paa);
+ **paa-- = NULL;
+ }
+ if (!*paa)
+ idp->layers = 0;
+ } else
+ idr_remove_warning(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;
+
+ id = starting_id;
+build_up:
+ p = idp->top;
+ layers = idp->layers;
+ if (!p) {
+ p = alloc_layer(idp);
+ if (!p)
+ return -1;
+ 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)
+ continue;
+ new = alloc_layer(idp);
+ if (!new) {
+ /*
+ * The allocation failed. If we built part of
+ * the structure tear it down.
+ */
+ for (new = p; p && p != idp->top; new = p) {
+ p = p->ary[0];
+ new->ary[0] = NULL;
+ new->bitmap = new->count = 0;
+ __free_layer(idp, new);
+ }
+ return -1;
+ }
+ new->ary[0] = p;
+ new->count = 1;
+ if (p->bitmap == IDR_FULL)
+ __set_bit(0, &new->bitmap);
+ p = new;
+ }
+ idp->top = p;
+ idp->layers = layers;
+ v = sub_alloc(idp, &id, pa);
+ if (v == -2)
+ goto build_up;
+ return v;
+}
+
+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) {
+ p = pa[++l];
+ if (!p)
+ break;
+ id = id >> IDR_BITS;
+ __set_bit((id & IDR_MASK), &p->bitmap);
+ }
+}
+
+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.
+ */
+ pa[0]->ary[id & IDR_MASK] = (struct idr_layer *)ptr;
+ pa[0]->count++;
+ idr_mark_full(pa, id);
+ }
+
+ return id;
+}
+
+
+/**
+ * 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().
+ *
+ * The caller must serialize idr_find() vs idr_get_new() and idr_remove().
+ */
+void *idr_find(struct idr *idp, int id)
+{
+ int n;
+ struct idr_layer *p;
+
+ n = idp->layers * IDR_BITS;
+ p = idp->top;
+
+ /* Mask off upper bits we don't use for the search. */
+ id &= MAX_ID_MASK;
+
+ if (id >= (1 << n))
+ return NULL;
+
+ while (n > 0 && p) {
+ n -= IDR_BITS;
+ p = p->ary[(id >> n) & IDR_MASK];
+ }
+ return (void *)p;
+}
+EXPORT_SYMBOL(idr_find);
+
+/**
+ * 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;
+
+ /* 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]) {
+ /* We can drop a layer */
+ p = idp->top->ary[0];
+ idp->top->bitmap = idp->top->count = 0;
+ free_layer(idp, idp->top);
+ idp->top = p;
+ --idp->layers;
+ }
+ while (idp->id_free_cnt >= IDR_FREE_MAX) {
+ p = alloc_layer(idp);
+ free(p);
+ }
+ return;
+}
+EXPORT_SYMBOL(idr_remove);
+
+/**
+ * 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
+ * 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 idr_pre_get(struct idr *idp)
+{
+ while (idp->id_free_cnt < IDR_FREE_MAX) {
+ struct idr_layer *new;
+ new = malloc(sizeof(struct idr_layer));
+ if (new == NULL)
+ return 0;
+ free_layer(idp, new);
+ }
+ return 1;
+}
+EXPORT_SYMBOL(idr_pre_get);
+
+/**
+ * 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 0 ... 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) {
+ if (rv == -1)
+ return -EAGAIN;
+ else /* Will be -3 */
+ return -ENOSPC;
+ }
+ *id = rv;
+ return 0;
+}
+EXPORT_SYMBOL(idr_get_new_above);
Index: u-boot-v2.git/lib/Makefile
===================================================================
--- u-boot-v2.git.orig/lib/Makefile 2008-06-19 08:40:01.000000000 -0500
+++ u-boot-v2.git/lib/Makefile 2008-06-19 08:40:15.000000000 -0500
@@ -16,6 +16,7 @@
obj-y += stringlist.o
obj-y += recursive_action.o
obj-y += make_directory.o
+obj-y += idr.o
obj-$(CONFIG_BZLIB) += bzlib.o bzlib_crctable.o bzlib_decompress.o bzlib_huffman.o bzlib_randtable.o
obj-$(CONFIG_ZLIB) += zlib.o gunzip.o
obj-$(CONFIG_CRC32) += crc32.o
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