[PATCH v2] pcm_native: Remove VLA usage

From: Kyle Spiers
Date: Wed Mar 28 2018 - 18:24:08 EST


As part of the effort to remove VLAs from the kernel[1], this changes
the allocation of the rstamps array from being on the stack to being
kcalloc()ed. This also allows for the removal of the explicit zeroing
loop.

Signed-off-by: Kyle Spiers <kyle@xxxxxxxxx>
---
sound/core/pcm_native.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 77ba50d..db5e3c5 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -323,7 +323,7 @@ static int constrain_params_by_rules(struct snd_pcm_substream *substream,
struct snd_pcm_hw_constraints *constrs =
&substream->runtime->hw_constraints;
unsigned int k;
- unsigned int rstamps[constrs->rules_num];
+ unsigned int *rstamps;
unsigned int vstamps[SNDRV_PCM_HW_PARAM_LAST_INTERVAL + 1];
unsigned int stamp;
struct snd_pcm_hw_rule *r;
@@ -339,8 +339,8 @@ static int constrain_params_by_rules(struct snd_pcm_substream *substream,
* Each member of 'rstamps' array represents the sequence number of
* recent application of corresponding rule.
*/
- for (k = 0; k < constrs->rules_num; k++)
- rstamps[k] = 0;
+
+ rstamps = kcalloc(constrs->rules_num, sizeof(*rstamps), GFP_KERNEL);

/*
* Each member of 'vstamps' array represents the sequence number of
@@ -398,8 +398,10 @@ static int constrain_params_by_rules(struct snd_pcm_substream *substream,
}

changed = r->func(params, r);
- if (changed < 0)
+ if (changed < 0) {
+ kfree(rstamps);
return changed;
+ }

/*
* When the parameter is changed, notify it to the caller
@@ -430,6 +432,7 @@ static int constrain_params_by_rules(struct snd_pcm_substream *substream,
if (again)
goto retry;

+ kfree(rstamps);
return 0;
}

--
2.7.4