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![Takashi Iwai](/assets/img/avatar_default.png)
The PCM memory allocation helpers have a sanity check against too many buffer allocations. However, the check is performed without a proper lock and the allocation isn't serialized; this allows user to allocate more memories than predefined max size. Practically seen, this isn't really a big problem, as it's more or less some "soft limit" as a sanity check, and it's not possible to allocate unlimitedly. But it's still better to address this for more consistent behavior. The patch covers the size check in do_alloc_pages() with the card->memory_mutex, and increases the allocated size there for preventing the further overflow. When the actual allocation fails, the size is decreased accordingly. Reported-by: BassCheck <bass@buaa.edu.cn> Reported-by: Tuo Li <islituo@gmail.com> Link: https://lore.kernel.org/r/CADm8Tek6t0WedK+3Y6rbE5YEt19tML8BUL45N2ji4ZAz1KcN_A@mail.gmail.com Reviewed-by: Jaroslav Kysela <perex@perex.cz> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20230703112430.30634-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
563 lines
17 KiB
C
563 lines
17 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Digital Audio (PCM) abstract layer
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* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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*/
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#include <linux/io.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/moduleparam.h>
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#include <linux/vmalloc.h>
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#include <linux/export.h>
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#include <sound/core.h>
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#include <sound/pcm.h>
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#include <sound/info.h>
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#include <sound/initval.h>
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#include "pcm_local.h"
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static int preallocate_dma = 1;
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module_param(preallocate_dma, int, 0444);
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MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
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static int maximum_substreams = 4;
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module_param(maximum_substreams, int, 0444);
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MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
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static const size_t snd_minimum_buffer = 16384;
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static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL;
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module_param(max_alloc_per_card, ulong, 0644);
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MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card.");
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static void __update_allocated_size(struct snd_card *card, ssize_t bytes)
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{
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card->total_pcm_alloc_bytes += bytes;
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}
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static void update_allocated_size(struct snd_card *card, ssize_t bytes)
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{
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mutex_lock(&card->memory_mutex);
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__update_allocated_size(card, bytes);
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mutex_unlock(&card->memory_mutex);
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}
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static void decrease_allocated_size(struct snd_card *card, size_t bytes)
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{
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mutex_lock(&card->memory_mutex);
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WARN_ON(card->total_pcm_alloc_bytes < bytes);
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__update_allocated_size(card, -(ssize_t)bytes);
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mutex_unlock(&card->memory_mutex);
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}
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static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
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int str, size_t size, struct snd_dma_buffer *dmab)
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{
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enum dma_data_direction dir;
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int err;
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/* check and reserve the requested size */
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mutex_lock(&card->memory_mutex);
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if (max_alloc_per_card &&
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card->total_pcm_alloc_bytes + size > max_alloc_per_card) {
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mutex_unlock(&card->memory_mutex);
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return -ENOMEM;
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}
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__update_allocated_size(card, size);
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mutex_unlock(&card->memory_mutex);
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if (str == SNDRV_PCM_STREAM_PLAYBACK)
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dir = DMA_TO_DEVICE;
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else
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dir = DMA_FROM_DEVICE;
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err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
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if (!err) {
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/* the actual allocation size might be bigger than requested,
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* and we need to correct the account
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*/
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if (dmab->bytes != size)
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update_allocated_size(card, dmab->bytes - size);
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} else {
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/* take back on allocation failure */
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decrease_allocated_size(card, size);
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}
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return err;
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}
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static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
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{
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if (!dmab->area)
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return;
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decrease_allocated_size(card, dmab->bytes);
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snd_dma_free_pages(dmab);
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dmab->area = NULL;
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}
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/*
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* try to allocate as the large pages as possible.
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* stores the resultant memory size in *res_size.
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*
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* the minimum size is snd_minimum_buffer. it should be power of 2.
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*/
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static int preallocate_pcm_pages(struct snd_pcm_substream *substream,
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size_t size, bool no_fallback)
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{
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struct snd_dma_buffer *dmab = &substream->dma_buffer;
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struct snd_card *card = substream->pcm->card;
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size_t orig_size = size;
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int err;
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do {
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err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
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substream->stream, size, dmab);
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if (err != -ENOMEM)
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return err;
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if (no_fallback)
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break;
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size >>= 1;
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} while (size >= snd_minimum_buffer);
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dmab->bytes = 0; /* tell error */
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pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
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substream->pcm->card->number, substream->pcm->device,
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substream->stream ? 'c' : 'p', substream->number,
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substream->pcm->name, orig_size);
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return -ENOMEM;
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}
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/**
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* snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
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* @substream: the pcm substream instance
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*
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* Releases the pre-allocated buffer of the given substream.
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*/
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void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
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{
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do_free_pages(substream->pcm->card, &substream->dma_buffer);
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}
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/**
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* snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
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* @pcm: the pcm instance
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*
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* Releases all the pre-allocated buffers on the given pcm.
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*/
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void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
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{
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struct snd_pcm_substream *substream;
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int stream;
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for_each_pcm_substream(pcm, stream, substream)
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snd_pcm_lib_preallocate_free(substream);
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}
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EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
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#ifdef CONFIG_SND_VERBOSE_PROCFS
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/*
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* read callback for prealloc proc file
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*
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* prints the current allocated size in kB.
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*/
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static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
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struct snd_info_buffer *buffer)
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{
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struct snd_pcm_substream *substream = entry->private_data;
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snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
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}
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/*
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* read callback for prealloc_max proc file
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*
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* prints the maximum allowed size in kB.
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*/
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static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
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struct snd_info_buffer *buffer)
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{
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struct snd_pcm_substream *substream = entry->private_data;
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snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
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}
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/*
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* write callback for prealloc proc file
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*
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* accepts the preallocation size in kB.
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*/
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static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
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struct snd_info_buffer *buffer)
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{
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struct snd_pcm_substream *substream = entry->private_data;
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struct snd_card *card = substream->pcm->card;
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char line[64], str[64];
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size_t size;
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struct snd_dma_buffer new_dmab;
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mutex_lock(&substream->pcm->open_mutex);
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if (substream->runtime) {
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buffer->error = -EBUSY;
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goto unlock;
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}
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if (!snd_info_get_line(buffer, line, sizeof(line))) {
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snd_info_get_str(str, line, sizeof(str));
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size = simple_strtoul(str, NULL, 10) * 1024;
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if ((size != 0 && size < 8192) || size > substream->dma_max) {
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buffer->error = -EINVAL;
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goto unlock;
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}
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if (substream->dma_buffer.bytes == size)
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goto unlock;
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memset(&new_dmab, 0, sizeof(new_dmab));
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new_dmab.dev = substream->dma_buffer.dev;
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if (size > 0) {
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if (do_alloc_pages(card,
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substream->dma_buffer.dev.type,
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substream->dma_buffer.dev.dev,
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substream->stream,
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size, &new_dmab) < 0) {
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buffer->error = -ENOMEM;
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pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
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substream->pcm->card->number, substream->pcm->device,
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substream->stream ? 'c' : 'p', substream->number,
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substream->pcm->name, size);
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goto unlock;
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}
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substream->buffer_bytes_max = size;
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} else {
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substream->buffer_bytes_max = UINT_MAX;
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}
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if (substream->dma_buffer.area)
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do_free_pages(card, &substream->dma_buffer);
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substream->dma_buffer = new_dmab;
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} else {
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buffer->error = -EINVAL;
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}
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unlock:
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mutex_unlock(&substream->pcm->open_mutex);
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}
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static inline void preallocate_info_init(struct snd_pcm_substream *substream)
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{
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struct snd_info_entry *entry;
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entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
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substream->proc_root);
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if (entry) {
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snd_info_set_text_ops(entry, substream,
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snd_pcm_lib_preallocate_proc_read);
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entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
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entry->mode |= 0200;
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}
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entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
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substream->proc_root);
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if (entry)
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snd_info_set_text_ops(entry, substream,
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snd_pcm_lib_preallocate_max_proc_read);
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}
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#else /* !CONFIG_SND_VERBOSE_PROCFS */
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static inline void preallocate_info_init(struct snd_pcm_substream *substream)
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{
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}
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#endif /* CONFIG_SND_VERBOSE_PROCFS */
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/*
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* pre-allocate the buffer and create a proc file for the substream
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*/
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static int preallocate_pages(struct snd_pcm_substream *substream,
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int type, struct device *data,
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size_t size, size_t max, bool managed)
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{
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int err;
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if (snd_BUG_ON(substream->dma_buffer.dev.type))
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return -EINVAL;
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substream->dma_buffer.dev.type = type;
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substream->dma_buffer.dev.dev = data;
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if (size > 0) {
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if (!max) {
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/* no fallback, only also inform -ENOMEM */
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err = preallocate_pcm_pages(substream, size, true);
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if (err < 0)
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return err;
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} else if (preallocate_dma &&
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substream->number < maximum_substreams) {
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err = preallocate_pcm_pages(substream, size, false);
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if (err < 0 && err != -ENOMEM)
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return err;
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}
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}
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if (substream->dma_buffer.bytes > 0)
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substream->buffer_bytes_max = substream->dma_buffer.bytes;
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substream->dma_max = max;
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if (max > 0)
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preallocate_info_init(substream);
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if (managed)
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substream->managed_buffer_alloc = 1;
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return 0;
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}
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static int preallocate_pages_for_all(struct snd_pcm *pcm, int type,
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void *data, size_t size, size_t max,
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bool managed)
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{
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struct snd_pcm_substream *substream;
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int stream, err;
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for_each_pcm_substream(pcm, stream, substream) {
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err = preallocate_pages(substream, type, data, size, max, managed);
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if (err < 0)
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return err;
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}
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return 0;
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}
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/**
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* snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
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* @substream: the pcm substream instance
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* @type: DMA type (SNDRV_DMA_TYPE_*)
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* @data: DMA type dependent data
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* @size: the requested pre-allocation size in bytes
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* @max: the max. allowed pre-allocation size
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*
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* Do pre-allocation for the given DMA buffer type.
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*/
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void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
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int type, struct device *data,
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size_t size, size_t max)
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{
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preallocate_pages(substream, type, data, size, max, false);
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}
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EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
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/**
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* snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
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* @pcm: the pcm instance
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* @type: DMA type (SNDRV_DMA_TYPE_*)
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* @data: DMA type dependent data
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* @size: the requested pre-allocation size in bytes
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* @max: the max. allowed pre-allocation size
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*
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* Do pre-allocation to all substreams of the given pcm for the
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* specified DMA type.
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*/
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void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
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int type, void *data,
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size_t size, size_t max)
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{
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preallocate_pages_for_all(pcm, type, data, size, max, false);
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}
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EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
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/**
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* snd_pcm_set_managed_buffer - set up buffer management for a substream
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* @substream: the pcm substream instance
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* @type: DMA type (SNDRV_DMA_TYPE_*)
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* @data: DMA type dependent data
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* @size: the requested pre-allocation size in bytes
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* @max: the max. allowed pre-allocation size
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*
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* Do pre-allocation for the given DMA buffer type, and set the managed
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* buffer allocation mode to the given substream.
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* In this mode, PCM core will allocate a buffer automatically before PCM
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* hw_params ops call, and release the buffer after PCM hw_free ops call
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* as well, so that the driver doesn't need to invoke the allocation and
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* the release explicitly in its callback.
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* When a buffer is actually allocated before the PCM hw_params call, it
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* turns on the runtime buffer_changed flag for drivers changing their h/w
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* parameters accordingly.
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*
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* When @size is non-zero and @max is zero, this tries to allocate for only
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* the exact buffer size without fallback, and may return -ENOMEM.
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* Otherwise, the function tries to allocate smaller chunks if the allocation
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* fails. This is the behavior of snd_pcm_set_fixed_buffer().
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*
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* When both @size and @max are zero, the function only sets up the buffer
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* for later dynamic allocations. It's used typically for buffers with
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* SNDRV_DMA_TYPE_VMALLOC type.
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*
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* Upon successful buffer allocation and setup, the function returns 0.
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*
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* Return: zero if successful, or a negative error code
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*/
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int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
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struct device *data, size_t size, size_t max)
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{
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return preallocate_pages(substream, type, data, size, max, true);
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}
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EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
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/**
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* snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
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* for all substreams
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* @pcm: the pcm instance
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* @type: DMA type (SNDRV_DMA_TYPE_*)
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* @data: DMA type dependent data
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* @size: the requested pre-allocation size in bytes
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* @max: the max. allowed pre-allocation size
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*
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* Do pre-allocation to all substreams of the given pcm for the specified DMA
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* type and size, and set the managed_buffer_alloc flag to each substream.
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*
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* Return: zero if successful, or a negative error code
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*/
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int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
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struct device *data,
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size_t size, size_t max)
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{
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return preallocate_pages_for_all(pcm, type, data, size, max, true);
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}
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EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
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/**
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* snd_pcm_lib_malloc_pages - allocate the DMA buffer
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* @substream: the substream to allocate the DMA buffer to
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* @size: the requested buffer size in bytes
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*
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* Allocates the DMA buffer on the BUS type given earlier to
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* snd_pcm_lib_preallocate_xxx_pages().
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*
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* Return: 1 if the buffer is changed, 0 if not changed, or a negative
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* code on failure.
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*/
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int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
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{
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struct snd_card *card;
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struct snd_pcm_runtime *runtime;
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struct snd_dma_buffer *dmab = NULL;
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if (PCM_RUNTIME_CHECK(substream))
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return -EINVAL;
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if (snd_BUG_ON(substream->dma_buffer.dev.type ==
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SNDRV_DMA_TYPE_UNKNOWN))
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return -EINVAL;
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runtime = substream->runtime;
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card = substream->pcm->card;
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if (runtime->dma_buffer_p) {
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/* perphaps, we might free the large DMA memory region
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to save some space here, but the actual solution
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costs us less time */
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if (runtime->dma_buffer_p->bytes >= size) {
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runtime->dma_bytes = size;
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return 0; /* ok, do not change */
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}
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snd_pcm_lib_free_pages(substream);
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}
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if (substream->dma_buffer.area != NULL &&
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substream->dma_buffer.bytes >= size) {
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dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
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} else {
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/* dma_max=0 means the fixed size preallocation */
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if (substream->dma_buffer.area && !substream->dma_max)
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return -ENOMEM;
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dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
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if (! dmab)
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return -ENOMEM;
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dmab->dev = substream->dma_buffer.dev;
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if (do_alloc_pages(card,
|
|
substream->dma_buffer.dev.type,
|
|
substream->dma_buffer.dev.dev,
|
|
substream->stream,
|
|
size, dmab) < 0) {
|
|
kfree(dmab);
|
|
pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
|
|
substream->pcm->card->number, substream->pcm->device,
|
|
substream->stream ? 'c' : 'p', substream->number,
|
|
substream->pcm->name, size);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
snd_pcm_set_runtime_buffer(substream, dmab);
|
|
runtime->dma_bytes = size;
|
|
return 1; /* area was changed */
|
|
}
|
|
EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
|
|
|
|
/**
|
|
* snd_pcm_lib_free_pages - release the allocated DMA buffer.
|
|
* @substream: the substream to release the DMA buffer
|
|
*
|
|
* Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
|
|
*
|
|
* Return: Zero if successful, or a negative error code on failure.
|
|
*/
|
|
int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
|
|
{
|
|
struct snd_pcm_runtime *runtime;
|
|
|
|
if (PCM_RUNTIME_CHECK(substream))
|
|
return -EINVAL;
|
|
runtime = substream->runtime;
|
|
if (runtime->dma_area == NULL)
|
|
return 0;
|
|
if (runtime->dma_buffer_p != &substream->dma_buffer) {
|
|
struct snd_card *card = substream->pcm->card;
|
|
|
|
/* it's a newly allocated buffer. release it now. */
|
|
do_free_pages(card, runtime->dma_buffer_p);
|
|
kfree(runtime->dma_buffer_p);
|
|
}
|
|
snd_pcm_set_runtime_buffer(substream, NULL);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(snd_pcm_lib_free_pages);
|
|
|
|
int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
|
|
size_t size, gfp_t gfp_flags)
|
|
{
|
|
struct snd_pcm_runtime *runtime;
|
|
|
|
if (PCM_RUNTIME_CHECK(substream))
|
|
return -EINVAL;
|
|
runtime = substream->runtime;
|
|
if (runtime->dma_area) {
|
|
if (runtime->dma_bytes >= size)
|
|
return 0; /* already large enough */
|
|
vfree(runtime->dma_area);
|
|
}
|
|
runtime->dma_area = __vmalloc(size, gfp_flags);
|
|
if (!runtime->dma_area)
|
|
return -ENOMEM;
|
|
runtime->dma_bytes = size;
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
|
|
|
|
/**
|
|
* snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
|
|
* @substream: the substream with a buffer allocated by
|
|
* snd_pcm_lib_alloc_vmalloc_buffer()
|
|
*
|
|
* Return: Zero if successful, or a negative error code on failure.
|
|
*/
|
|
int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
|
|
{
|
|
struct snd_pcm_runtime *runtime;
|
|
|
|
if (PCM_RUNTIME_CHECK(substream))
|
|
return -EINVAL;
|
|
runtime = substream->runtime;
|
|
vfree(runtime->dma_area);
|
|
runtime->dma_area = NULL;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
|
|
|
|
/**
|
|
* snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
|
|
* @substream: the substream with a buffer allocated by
|
|
* snd_pcm_lib_alloc_vmalloc_buffer()
|
|
* @offset: offset in the buffer
|
|
*
|
|
* This function is to be used as the page callback in the PCM ops.
|
|
*
|
|
* Return: The page struct, or %NULL on failure.
|
|
*/
|
|
struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
|
|
unsigned long offset)
|
|
{
|
|
return vmalloc_to_page(substream->runtime->dma_area + offset);
|
|
}
|
|
EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
|