[alsa-devel] [PATCH v2 21/27] ALSA: pcm: Unify read/write loop
Takashi Iwai
tiwai at suse.de
Thu Jun 1 22:58:44 CEST 2017
Both __snd_pcm_lib_read() and __snd_pcm_write() functions have almost
the same code to loop over samples. For simplification, this patch
unifies both as the single helper, __snd_pcm_lib_xfer().
Other than that, there should be no functional change by this patch.
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
include/sound/pcm.h | 13 ++--
sound/core/pcm_lib.c | 184 +++++++++++++--------------------------------------
2 files changed, 51 insertions(+), 146 deletions(-)
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index cb4eff8ffd2e..173c6a6ebf35 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -1088,10 +1088,7 @@ int snd_pcm_update_state(struct snd_pcm_substream *substream,
int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream);
void snd_pcm_playback_silence(struct snd_pcm_substream *substream, snd_pcm_uframes_t new_hw_ptr);
void snd_pcm_period_elapsed(struct snd_pcm_substream *substream);
-snd_pcm_sframes_t __snd_pcm_lib_write(struct snd_pcm_substream *substream,
- void *buf, bool interleaved,
- snd_pcm_uframes_t frames);
-snd_pcm_sframes_t __snd_pcm_lib_read(struct snd_pcm_substream *substream,
+snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
void *buf, bool interleaved,
snd_pcm_uframes_t frames);
@@ -1099,28 +1096,28 @@ static inline snd_pcm_sframes_t
snd_pcm_lib_write(struct snd_pcm_substream *substream,
const void __user *buf, snd_pcm_uframes_t frames)
{
- return __snd_pcm_lib_write(substream, (void *)buf, true, frames);
+ return __snd_pcm_lib_xfer(substream, (void *)buf, true, frames);
}
static inline snd_pcm_sframes_t
snd_pcm_lib_read(struct snd_pcm_substream *substream,
void __user *buf, snd_pcm_uframes_t frames)
{
- return __snd_pcm_lib_read(substream, (void *)buf, true, frames);
+ return __snd_pcm_lib_xfer(substream, (void *)buf, true, frames);
}
static inline snd_pcm_sframes_t
snd_pcm_lib_writev(struct snd_pcm_substream *substream,
void __user **bufs, snd_pcm_uframes_t frames)
{
- return __snd_pcm_lib_write(substream, (void *)bufs, false, frames);
+ return __snd_pcm_lib_xfer(substream, (void *)bufs, false, frames);
}
static inline snd_pcm_sframes_t
snd_pcm_lib_readv(struct snd_pcm_substream *substream,
void __user **bufs, snd_pcm_uframes_t frames)
{
- return __snd_pcm_lib_read(substream, (void *)bufs, false, frames);
+ return __snd_pcm_lib_xfer(substream, (void *)bufs, false, frames);
}
extern const struct snd_pcm_hw_constraint_list snd_pcm_known_rates;
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index eb9cbc2d9d7b..f15460eaf8b5 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -2006,13 +2006,13 @@ static void *get_dma_ptr(struct snd_pcm_runtime *runtime,
channel * (runtime->dma_bytes / runtime->channels);
}
-/* default copy_user ops for write */
-static int default_write_copy_user(struct snd_pcm_substream *substream,
- int channel, unsigned long hwoff,
- void __user *buf, unsigned long bytes)
+/* default copy_user ops for write; used for both interleaved and non- modes */
+static int default_write_copy(struct snd_pcm_substream *substream,
+ int channel, unsigned long hwoff,
+ void *buf, unsigned long bytes)
{
if (copy_from_user(get_dma_ptr(substream->runtime, channel, hwoff),
- buf, bytes))
+ (void __user *)buf, bytes))
return -EFAULT;
return 0;
}
@@ -2038,6 +2038,18 @@ static int fill_silence(struct snd_pcm_substream *substream, int channel,
return 0;
}
+/* default copy_user ops for read; used for both interleaved and non- modes */
+static int default_read_copy(struct snd_pcm_substream *substream,
+ int channel, unsigned long hwoff,
+ void *buf, unsigned long bytes)
+{
+ if (copy_to_user((void __user *)buf,
+ get_dma_ptr(substream->runtime, channel, hwoff),
+ bytes))
+ return -EFAULT;
+ return 0;
+}
+
/* call transfer function with the converted pointers and sizes;
* for interleaved mode, it's one shot for all samples
*/
@@ -2119,9 +2131,10 @@ static int pcm_accessible_state(struct snd_pcm_runtime *runtime)
}
}
-snd_pcm_sframes_t __snd_pcm_lib_write(struct snd_pcm_substream *substream,
- void *data, bool interleaved,
- snd_pcm_uframes_t size)
+/* the common loop for read/write data */
+snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
+ void *data, bool interleaved,
+ snd_pcm_uframes_t size)
{
struct snd_pcm_runtime *runtime = substream->runtime;
snd_pcm_uframes_t xfer = 0;
@@ -2130,12 +2143,14 @@ snd_pcm_sframes_t __snd_pcm_lib_write(struct snd_pcm_substream *substream,
pcm_copy_f writer;
pcm_transfer_f transfer;
bool nonblock;
+ bool is_playback;
int err;
err = pcm_sanity_check(substream);
if (err < 0)
return err;
+ is_playback = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
if (interleaved) {
if (runtime->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED &&
runtime->channels > 1)
@@ -2148,12 +2163,16 @@ snd_pcm_sframes_t __snd_pcm_lib_write(struct snd_pcm_substream *substream,
}
if (!data) {
- transfer = fill_silence;
+ if (is_playback)
+ transfer = fill_silence;
+ else
+ return -EINVAL;
} else {
if (substream->ops->copy_user)
transfer = (pcm_transfer_f)substream->ops->copy_user;
else
- transfer = default_write_copy_user;
+ transfer = is_playback ?
+ default_write_copy : default_read_copy;
}
if (size == 0)
@@ -2166,129 +2185,8 @@ snd_pcm_sframes_t __snd_pcm_lib_write(struct snd_pcm_substream *substream,
if (err < 0)
goto _end_unlock;
- runtime->twake = runtime->control->avail_min ? : 1;
- if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)
- snd_pcm_update_hw_ptr(substream);
- avail = snd_pcm_playback_avail(runtime);
- while (size > 0) {
- snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
- snd_pcm_uframes_t cont;
- if (!avail) {
- if (nonblock) {
- err = -EAGAIN;
- goto _end_unlock;
- }
- runtime->twake = min_t(snd_pcm_uframes_t, size,
- runtime->control->avail_min ? : 1);
- err = wait_for_avail(substream, &avail);
- if (err < 0)
- goto _end_unlock;
- }
- frames = size > avail ? avail : size;
- cont = runtime->buffer_size - runtime->control->appl_ptr % runtime->buffer_size;
- if (frames > cont)
- frames = cont;
- if (snd_BUG_ON(!frames)) {
- runtime->twake = 0;
- snd_pcm_stream_unlock_irq(substream);
- return -EINVAL;
- }
- appl_ptr = runtime->control->appl_ptr;
- appl_ofs = appl_ptr % runtime->buffer_size;
- snd_pcm_stream_unlock_irq(substream);
- err = writer(substream, appl_ofs, data, offset, frames,
- transfer);
- snd_pcm_stream_lock_irq(substream);
- if (err < 0)
- goto _end_unlock;
- err = pcm_accessible_state(runtime);
- if (err < 0)
- goto _end_unlock;
- appl_ptr += frames;
- if (appl_ptr >= runtime->boundary)
- appl_ptr -= runtime->boundary;
- runtime->control->appl_ptr = appl_ptr;
- if (substream->ops->ack)
- substream->ops->ack(substream);
-
- offset += frames;
- size -= frames;
- xfer += frames;
- avail -= frames;
- if (runtime->status->state == SNDRV_PCM_STATE_PREPARED &&
- snd_pcm_playback_hw_avail(runtime) >= (snd_pcm_sframes_t)runtime->start_threshold) {
- err = snd_pcm_start(substream);
- if (err < 0)
- goto _end_unlock;
- }
- }
- _end_unlock:
- runtime->twake = 0;
- if (xfer > 0 && err >= 0)
- snd_pcm_update_state(substream, runtime);
- snd_pcm_stream_unlock_irq(substream);
- return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
-}
-EXPORT_SYMBOL(__snd_pcm_lib_write);
-
-/* default copy_user ops for read */
-static int default_read_copy_user(struct snd_pcm_substream *substream,
- int channel, unsigned long hwoff,
- void *buf, unsigned long bytes)
-{
- if (copy_to_user((void __user *)buf,
- get_dma_ptr(substream->runtime, channel, hwoff),
- bytes))
- return -EFAULT;
- return 0;
-}
-
-snd_pcm_sframes_t __snd_pcm_lib_read(struct snd_pcm_substream *substream,
- void *data, bool interleaved,
- snd_pcm_uframes_t size)
-{
- struct snd_pcm_runtime *runtime = substream->runtime;
- snd_pcm_uframes_t xfer = 0;
- snd_pcm_uframes_t offset = 0;
- snd_pcm_uframes_t avail;
- pcm_copy_f reader;
- pcm_transfer_f transfer;
- bool nonblock;
- int err;
-
- err = pcm_sanity_check(substream);
- if (err < 0)
- return err;
-
- if (!data)
- return -EINVAL;
-
- if (interleaved) {
- if (runtime->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED &&
- runtime->channels > 1)
- return -EINVAL;
- reader = interleaved_copy;
- } else {
- if (runtime->access != SNDRV_PCM_ACCESS_RW_NONINTERLEAVED)
- return -EINVAL;
- reader = noninterleaved_copy;
- }
-
- if (substream->ops->copy_user)
- transfer = (pcm_transfer_f)substream->ops->copy_user;
- else
- transfer = default_read_copy_user;
-
- if (size == 0)
- return 0;
-
- nonblock = !!(substream->f_flags & O_NONBLOCK);
-
- snd_pcm_stream_lock_irq(substream);
- err = pcm_accessible_state(runtime);
- if (err < 0)
- goto _end_unlock;
- if (runtime->status->state == SNDRV_PCM_STATE_PREPARED &&
+ if (!is_playback &&
+ runtime->status->state == SNDRV_PCM_STATE_PREPARED &&
size >= runtime->start_threshold) {
err = snd_pcm_start(substream);
if (err < 0)
@@ -2298,13 +2196,16 @@ snd_pcm_sframes_t __snd_pcm_lib_read(struct snd_pcm_substream *substream,
runtime->twake = runtime->control->avail_min ? : 1;
if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)
snd_pcm_update_hw_ptr(substream);
- avail = snd_pcm_capture_avail(runtime);
+ if (is_playback)
+ avail = snd_pcm_playback_avail(runtime);
+ else
+ avail = snd_pcm_capture_avail(runtime);
while (size > 0) {
snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
snd_pcm_uframes_t cont;
if (!avail) {
- if (runtime->status->state ==
- SNDRV_PCM_STATE_DRAINING) {
+ if (!is_playback &&
+ runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
snd_pcm_stop(substream, SNDRV_PCM_STATE_SETUP);
goto _end_unlock;
}
@@ -2332,7 +2233,7 @@ snd_pcm_sframes_t __snd_pcm_lib_read(struct snd_pcm_substream *substream,
appl_ptr = runtime->control->appl_ptr;
appl_ofs = appl_ptr % runtime->buffer_size;
snd_pcm_stream_unlock_irq(substream);
- err = reader(substream, appl_ofs, data, offset, frames,
+ err = writer(substream, appl_ofs, data, offset, frames,
transfer);
snd_pcm_stream_lock_irq(substream);
if (err < 0)
@@ -2351,6 +2252,13 @@ snd_pcm_sframes_t __snd_pcm_lib_read(struct snd_pcm_substream *substream,
size -= frames;
xfer += frames;
avail -= frames;
+ if (is_playback &&
+ runtime->status->state == SNDRV_PCM_STATE_PREPARED &&
+ snd_pcm_playback_hw_avail(runtime) >= (snd_pcm_sframes_t)runtime->start_threshold) {
+ err = snd_pcm_start(substream);
+ if (err < 0)
+ goto _end_unlock;
+ }
}
_end_unlock:
runtime->twake = 0;
@@ -2359,7 +2267,7 @@ snd_pcm_sframes_t __snd_pcm_lib_read(struct snd_pcm_substream *substream,
snd_pcm_stream_unlock_irq(substream);
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
-EXPORT_SYMBOL(__snd_pcm_lib_read);
+EXPORT_SYMBOL(__snd_pcm_lib_xfer);
/*
* standard channel mapping helpers
--
2.13.0
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