[alsa-devel] [PATCH] ALSA: pcm: add const qualifier for read-only table for sampling rate
There's a read-only table for each sampling rate, while it doesn't have const qualifier and can be modified.
This commit add the qualifier. As a result, a symbol for the table moves from .data section to .rodata.
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/core/pcm_native.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index d873f90..f3a3580 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -1987,8 +1987,10 @@ static int snd_pcm_hw_rule_sample_bits(struct snd_pcm_hw_params *params, #error "Change this table" #endif
-static unsigned int rates[] = { 5512, 8000, 11025, 16000, 22050, 32000, 44100, - 48000, 64000, 88200, 96000, 176400, 192000 }; +static const unsigned int rates[] = { + 5512, 8000, 11025, 16000, 22050, 32000, 44100, + 48000, 64000, 88200, 96000, 176400, 192000 +};
const struct snd_pcm_hw_constraint_list snd_pcm_known_rates = { .count = ARRAY_SIZE(rates),
In a function snd_pcm_hw_params_choose(), target parameters are arranged into a table. Though each entry of this table is read-only, they don't have const qualifier.
This commit adds the qualifier.
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/core/pcm_lib.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index af439e5..ab4b1d1 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1734,7 +1734,7 @@ EXPORT_SYMBOL(snd_pcm_hw_param_last); int snd_pcm_hw_params_choose(struct snd_pcm_substream *pcm, struct snd_pcm_hw_params *params) { - static int vars[] = { + static const int vars[] = { SNDRV_PCM_HW_PARAM_ACCESS, SNDRV_PCM_HW_PARAM_FORMAT, SNDRV_PCM_HW_PARAM_SUBFORMAT, @@ -1745,7 +1745,8 @@ int snd_pcm_hw_params_choose(struct snd_pcm_substream *pcm, SNDRV_PCM_HW_PARAM_TICK_TIME, -1 }; - int err, *v; + const int *v; + int err;
for (v = vars; *v != -1; v++) { if (*v != SNDRV_PCM_HW_PARAM_BUFFER_SIZE)
Some functions in compatibility layer for Open Sound System interface has local variable to copy some parameters in runtime of PCM substream, while this can be replaced with reference of pointers to parameter itself. This brings an advantage to reduce usage of kernel stack.
This commit applies this idea.
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/core/oss/pcm_oss.c | 16 ++++++++-------- sound/core/oss/pcm_plugin.c | 5 +++-- sound/core/oss/pcm_plugin.h | 2 +- 3 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c index 2a47351..e306f05 100644 --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -848,7 +848,7 @@ static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream, int direct; snd_pcm_format_t format, sformat; int n; - struct snd_mask sformat_mask; + const struct snd_mask *sformat_mask; struct snd_mask mask;
if (trylock) { @@ -891,18 +891,18 @@ static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream,
format = snd_pcm_oss_format_from(runtime->oss.format);
- sformat_mask = *hw_param_mask(sparams, SNDRV_PCM_HW_PARAM_FORMAT); + sformat_mask = hw_param_mask_c(sparams, SNDRV_PCM_HW_PARAM_FORMAT); if (direct) sformat = format; else - sformat = snd_pcm_plug_slave_format(format, &sformat_mask); + sformat = snd_pcm_plug_slave_format(format, sformat_mask);
if ((__force int)sformat < 0 || - !snd_mask_test(&sformat_mask, (__force int)sformat)) { + !snd_mask_test(sformat_mask, (__force int)sformat)) { for (sformat = (__force snd_pcm_format_t)0; (__force int)sformat <= (__force int)SNDRV_PCM_FORMAT_LAST; sformat = (__force snd_pcm_format_t)((__force int)sformat + 1)) { - if (snd_mask_test(&sformat_mask, (__force int)sformat) && + if (snd_mask_test(sformat_mask, (__force int)sformat) && snd_pcm_oss_format_to(sformat) >= 0) break; } @@ -1780,7 +1780,7 @@ static int snd_pcm_oss_get_formats(struct snd_pcm_oss_file *pcm_oss_file) int direct; struct snd_pcm_hw_params *params; unsigned int formats = 0; - struct snd_mask format_mask; + const struct snd_mask *format_mask; int fmt;
if ((err = snd_pcm_oss_get_active_substream(pcm_oss_file, &substream)) < 0) @@ -1802,12 +1802,12 @@ static int snd_pcm_oss_get_formats(struct snd_pcm_oss_file *pcm_oss_file) return -ENOMEM; _snd_pcm_hw_params_any(params); err = snd_pcm_hw_refine(substream, params); - format_mask = *hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT); + format_mask = hw_param_mask_c(params, SNDRV_PCM_HW_PARAM_FORMAT); kfree(params); if (err < 0) return err; for (fmt = 0; fmt < 32; ++fmt) { - if (snd_mask_test(&format_mask, fmt)) { + if (snd_mask_test(format_mask, fmt)) { int f = snd_pcm_oss_format_to(fmt); if (f >= 0) formats |= f; diff --git a/sound/core/oss/pcm_plugin.c b/sound/core/oss/pcm_plugin.c index 727ac44..cadc937 100644 --- a/sound/core/oss/pcm_plugin.c +++ b/sound/core/oss/pcm_plugin.c @@ -266,7 +266,8 @@ snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pc return frames; }
-static int snd_pcm_plug_formats(struct snd_mask *mask, snd_pcm_format_t format) +static int snd_pcm_plug_formats(const struct snd_mask *mask, + snd_pcm_format_t format) { struct snd_mask formats = *mask; u64 linfmts = (SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 | @@ -309,7 +310,7 @@ static snd_pcm_format_t preferred_formats[] = { };
snd_pcm_format_t snd_pcm_plug_slave_format(snd_pcm_format_t format, - struct snd_mask *format_mask) + const struct snd_mask *format_mask) { int i;
diff --git a/sound/core/oss/pcm_plugin.h b/sound/core/oss/pcm_plugin.h index a5035c2..38e2c14 100644 --- a/sound/core/oss/pcm_plugin.h +++ b/sound/core/oss/pcm_plugin.h @@ -126,7 +126,7 @@ int snd_pcm_plug_format_plugins(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *slave_params);
snd_pcm_format_t snd_pcm_plug_slave_format(snd_pcm_format_t format, - struct snd_mask *format_mask); + const struct snd_mask *format_mask);
int snd_pcm_plugin_append(struct snd_pcm_plugin *plugin);
ALSA pcm core has hw_param_interval_c() to pick up parameter with const qualifier for safe programming.
This commit applies it to the cases.
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/core/oss/pcm_oss.c | 4 ++-- sound/core/pcm_drm_eld.c | 8 ++++---- sound/core/pcm_lib.c | 3 ++- sound/core/pcm_native.c | 3 ++- 4 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c index 36baf96..2a47351 100644 --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -799,7 +799,7 @@ static int snd_pcm_oss_period_size(struct snd_pcm_substream *substream, static int choose_rate(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params, unsigned int best_rate) { - struct snd_interval *it; + const struct snd_interval *it; struct snd_pcm_hw_params *save; unsigned int rate, prev;
@@ -807,7 +807,7 @@ static int choose_rate(struct snd_pcm_substream *substream, if (save == NULL) return -ENOMEM; *save = *params; - it = hw_param_interval(save, SNDRV_PCM_HW_PARAM_RATE); + it = hw_param_interval_c(save, SNDRV_PCM_HW_PARAM_RATE);
/* try multiples of the best rate */ rate = best_rate; diff --git a/sound/core/pcm_drm_eld.c b/sound/core/pcm_drm_eld.c index e70379f..9881d08 100644 --- a/sound/core/pcm_drm_eld.c +++ b/sound/core/pcm_drm_eld.c @@ -29,13 +29,13 @@ static int eld_limit_rates(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule) { struct snd_interval *r = hw_param_interval(params, rule->var); - struct snd_interval *c; + const struct snd_interval *c; unsigned int rate_mask = 7, i; const u8 *sad, *eld = rule->private;
sad = drm_eld_sad(eld); if (sad) { - c = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS); + c = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
for (i = drm_eld_sad_count(eld); i > 0; i--, sad += 3) { unsigned max_channels = sad_max_channels(sad); @@ -57,7 +57,7 @@ static int eld_limit_channels(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule) { struct snd_interval *c = hw_param_interval(params, rule->var); - struct snd_interval *r; + const struct snd_interval *r; struct snd_interval t = { .min = 1, .max = 2, .integer = 1, }; unsigned int i; const u8 *sad, *eld = rule->private; @@ -67,7 +67,7 @@ static int eld_limit_channels(struct snd_pcm_hw_params *params, unsigned int rate_mask = 0;
/* Convert the rate interval to a mask */ - r = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE); + r = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE); for (i = 0; i < ARRAY_SIZE(eld_rates); i++) if (r->min <= eld_rates[i] && r->max >= eld_rates[i]) rate_mask |= BIT(i); diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 5088d4b..af439e5 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1415,7 +1415,8 @@ static int snd_pcm_hw_rule_msbits(struct snd_pcm_hw_params *params, unsigned int l = (unsigned long) rule->private; int width = l & 0xffff; unsigned int msbits = l >> 16; - struct snd_interval *i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS); + const struct snd_interval *i = + hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS);
if (!snd_interval_single(i)) return 0; diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 13dec5e..d873f90 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -1940,7 +1940,8 @@ static int snd_pcm_hw_rule_format(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule) { unsigned int k; - struct snd_interval *i = hw_param_interval(params, rule->deps[0]); + const struct snd_interval *i = + hw_param_interval_c(params, rule->deps[0]); struct snd_mask m; struct snd_mask *mask = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT); snd_mask_any(&m);
On Wed, 17 May 2017 01:48:17 +0200, Takashi Sakamoto wrote:
There's a read-only table for each sampling rate, while it doesn't have const qualifier and can be modified.
This commit add the qualifier. As a result, a symbol for the table moves from .data section to .rodata.
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp
Thanks, applied all four patches now.
Takashi
participants (2)
-
Takashi Iwai -
Takashi Sakamoto