183 строки
3.7 KiB
C
183 строки
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2000 Takashi Iwai <tiwai@suse.de>
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*
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* Generic memory management routines for soundcard memory allocation
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*/
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#include <linux/mutex.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <sound/core.h>
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#include <sound/util_mem.h>
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MODULE_AUTHOR("Takashi Iwai");
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MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
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MODULE_LICENSE("GPL");
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#define get_memblk(p) list_entry(p, struct snd_util_memblk, list)
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/*
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* create a new memory manager
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*/
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struct snd_util_memhdr *
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snd_util_memhdr_new(int memsize)
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{
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struct snd_util_memhdr *hdr;
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hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
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if (hdr == NULL)
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return NULL;
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hdr->size = memsize;
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mutex_init(&hdr->block_mutex);
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INIT_LIST_HEAD(&hdr->block);
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return hdr;
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}
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/*
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* free a memory manager
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*/
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void snd_util_memhdr_free(struct snd_util_memhdr *hdr)
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{
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struct list_head *p;
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if (!hdr)
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return;
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/* release all blocks */
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while ((p = hdr->block.next) != &hdr->block) {
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list_del(p);
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kfree(get_memblk(p));
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}
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kfree(hdr);
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}
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/*
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* allocate a memory block (without mutex)
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*/
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struct snd_util_memblk *
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__snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
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{
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struct snd_util_memblk *blk;
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unsigned int units, prev_offset;
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struct list_head *p;
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if (snd_BUG_ON(!hdr || size <= 0))
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return NULL;
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/* word alignment */
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units = size;
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if (units & 1)
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units++;
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if (units > hdr->size)
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return NULL;
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/* look for empty block */
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prev_offset = 0;
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list_for_each(p, &hdr->block) {
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blk = get_memblk(p);
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if (blk->offset - prev_offset >= units)
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goto __found;
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prev_offset = blk->offset + blk->size;
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}
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if (hdr->size - prev_offset < units)
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return NULL;
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__found:
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return __snd_util_memblk_new(hdr, units, p->prev);
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}
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/*
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* create a new memory block with the given size
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* the block is linked next to prev
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*/
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struct snd_util_memblk *
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__snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,
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struct list_head *prev)
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{
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struct snd_util_memblk *blk;
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blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,
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GFP_KERNEL);
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if (blk == NULL)
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return NULL;
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if (prev == &hdr->block)
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blk->offset = 0;
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else {
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struct snd_util_memblk *p = get_memblk(prev);
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blk->offset = p->offset + p->size;
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}
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blk->size = units;
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list_add(&blk->list, prev);
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hdr->nblocks++;
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hdr->used += units;
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return blk;
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}
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/*
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* allocate a memory block (with mutex)
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*/
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struct snd_util_memblk *
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snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
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{
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struct snd_util_memblk *blk;
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mutex_lock(&hdr->block_mutex);
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blk = __snd_util_mem_alloc(hdr, size);
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mutex_unlock(&hdr->block_mutex);
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return blk;
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}
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/*
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* remove the block from linked-list and free resource
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* (without mutex)
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*/
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void
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__snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
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{
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list_del(&blk->list);
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hdr->nblocks--;
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hdr->used -= blk->size;
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kfree(blk);
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}
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/*
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* free a memory block (with mutex)
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*/
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int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
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{
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if (snd_BUG_ON(!hdr || !blk))
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return -EINVAL;
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mutex_lock(&hdr->block_mutex);
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__snd_util_mem_free(hdr, blk);
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mutex_unlock(&hdr->block_mutex);
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return 0;
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}
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/*
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* return available memory size
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*/
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int snd_util_mem_avail(struct snd_util_memhdr *hdr)
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{
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unsigned int size;
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mutex_lock(&hdr->block_mutex);
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size = hdr->size - hdr->used;
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mutex_unlock(&hdr->block_mutex);
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return size;
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}
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EXPORT_SYMBOL(snd_util_memhdr_new);
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EXPORT_SYMBOL(snd_util_memhdr_free);
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EXPORT_SYMBOL(snd_util_mem_alloc);
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EXPORT_SYMBOL(snd_util_mem_free);
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EXPORT_SYMBOL(snd_util_mem_avail);
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EXPORT_SYMBOL(__snd_util_mem_alloc);
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EXPORT_SYMBOL(__snd_util_mem_free);
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EXPORT_SYMBOL(__snd_util_memblk_new);
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