[alsa-devel] [PATCH 6/8] ALSA: pcm: Use a macro for parameter masks to reduce the needed cast

[Takashi Iwai]

The parameter bit mask needs often explicit cast with __force,
e.g. for the PCM subformat type.  Instead of adding __force at each
place, which is error prone, this patch introduces a new macro and
replaces the all bit shift with it.  This fixes the sparse warnings
like the following:
  sound/core/pcm_native.c:2508:30: warning: restricted snd_pcm_access_t degrades to integer

No functional changes, just sparse warning fixes.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/core/pcm_native.c | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 900f9cfd4646..559633d4702d 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -228,6 +228,9 @@ int snd_pcm_info_user(struct snd_pcm_substream *substream,
 	return err;
 }
 
+/* macro for simplified cast */
+#define PARAM_MASK_BIT(b)	(1U << (__force int)(b))
+
 static bool hw_support_mmap(struct snd_pcm_substream *substream)
 {
 	if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP))
@@ -257,7 +260,7 @@ static int constrain_mask_params(struct snd_pcm_substream *substream,
 			return -EINVAL;
 
 		/* This parameter is not requested to change by a caller. */
-		if (!(params->rmask & (1 << k)))
+		if (!(params->rmask & PARAM_MASK_BIT(k)))
 			continue;
 
 		if (trace_hw_mask_param_enabled())
@@ -271,7 +274,7 @@ static int constrain_mask_params(struct snd_pcm_substream *substream,
 
 		/* Set corresponding flag so that the caller gets it. */
 		trace_hw_mask_param(substream, k, 0, &old_mask, m);
-		params->cmask |= 1 << k;
+		params->cmask |= PARAM_MASK_BIT(k);
 	}
 
 	return 0;
@@ -293,7 +296,7 @@ static int constrain_interval_params(struct snd_pcm_substream *substream,
 			return -EINVAL;
 
 		/* This parameter is not requested to change by a caller. */
-		if (!(params->rmask & (1 << k)))
+		if (!(params->rmask & PARAM_MASK_BIT(k)))
 			continue;
 
 		if (trace_hw_interval_param_enabled())
@@ -307,7 +310,7 @@ static int constrain_interval_params(struct snd_pcm_substream *substream,
 
 		/* Set corresponding flag so that the caller gets it. */
 		trace_hw_interval_param(substream, k, 0, &old_interval, i);
-		params->cmask |= 1 << k;
+		params->cmask |= PARAM_MASK_BIT(k);
 	}
 
 	return 0;
@@ -349,7 +352,7 @@ static int constrain_params_by_rules(struct snd_pcm_substream *substream,
 	 * have 0 so that the parameters are never changed anymore.
 	 */
 	for (k = 0; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++)
-		vstamps[k] = (params->rmask & (1 << k)) ? 1 : 0;
+		vstamps[k] = (params->rmask & PARAM_MASK_BIT(k)) ? 1 : 0;
 
 	/* Due to the above design, actual sequence number starts at 2. */
 	stamp = 2;
@@ -417,7 +420,7 @@ static int constrain_params_by_rules(struct snd_pcm_substream *substream,
 					hw_param_interval(params, r->var));
 			}
 
-			params->cmask |= (1 << r->var);
+			params->cmask |= PARAM_MASK_BIT(r->var);
 			vstamps[r->var] = stamp;
 			again = true;
 		}
@@ -486,9 +489,9 @@ int snd_pcm_hw_refine(struct snd_pcm_substream *substream,
 
 	params->info = 0;
 	params->fifo_size = 0;
-	if (params->rmask & (1 << SNDRV_PCM_HW_PARAM_SAMPLE_BITS))
+	if (params->rmask & PARAM_MASK_BIT(SNDRV_PCM_HW_PARAM_SAMPLE_BITS))
 		params->msbits = 0;
-	if (params->rmask & (1 << SNDRV_PCM_HW_PARAM_RATE)) {
+	if (params->rmask & PARAM_MASK_BIT(SNDRV_PCM_HW_PARAM_RATE)) {
 		params->rate_num = 0;
 		params->rate_den = 0;
 	}
@@ -2506,16 +2509,16 @@ static int snd_pcm_hw_constraints_complete(struct snd_pcm_substream *substream)
 	unsigned int mask = 0;
 
         if (hw->info & SNDRV_PCM_INFO_INTERLEAVED)
-		mask |= 1 << SNDRV_PCM_ACCESS_RW_INTERLEAVED;
+		mask |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_RW_INTERLEAVED);
         if (hw->info & SNDRV_PCM_INFO_NONINTERLEAVED)
-		mask |= 1 << SNDRV_PCM_ACCESS_RW_NONINTERLEAVED;
+		mask |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
 	if (hw_support_mmap(substream)) {
 		if (hw->info & SNDRV_PCM_INFO_INTERLEAVED)
-			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_INTERLEAVED;
+			mask |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_MMAP_INTERLEAVED);
 		if (hw->info & SNDRV_PCM_INFO_NONINTERLEAVED)
-			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED;
+			mask |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED);
 		if (hw->info & SNDRV_PCM_INFO_COMPLEX)
-			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_COMPLEX;
+			mask |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_MMAP_COMPLEX);
 	}
 	err = snd_pcm_hw_constraint_mask(runtime, SNDRV_PCM_HW_PARAM_ACCESS, mask);
 	if (err < 0)
@@ -2525,7 +2528,8 @@ static int snd_pcm_hw_constraints_complete(struct snd_pcm_substream *substream)
 	if (err < 0)
 		return err;
 
-	err = snd_pcm_hw_constraint_mask(runtime, SNDRV_PCM_HW_PARAM_SUBFORMAT, 1 << SNDRV_PCM_SUBFORMAT_STD);
+	err = snd_pcm_hw_constraint_mask(runtime, SNDRV_PCM_HW_PARAM_SUBFORMAT,
+					 PARAM_MASK_BIT(SNDRV_PCM_SUBFORMAT_STD));
 	if (err < 0)
 		return err;
 
-- 
2.16.4