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182 lines
3.7 KiB
182 lines
3.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright (C) 2000 Takashi Iwai <[email protected]> |
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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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