ALSA: rme9652: Convert to generic PCM copy ops

This patch converts the rme9652 driver code to use the new unified PCM
copy callback.  It's a straightforward conversion from *_user() to
*_iter() variants.

Note that copy_from/to_iter() returns the copied bytes, hence the
error condition is adjusted accordingly.

Link: https://lore.kernel.org/r/20230815190136.8987-14-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/rme9652/rme9652.c

@@ -1844,7 +1844,7 @@ static signed char *rme9652_channel_buffer_location(struct snd_rme9652 *rme9652,
 
 static int snd_rme9652_playback_copy(struct snd_pcm_substream *substream,
 				     int channel, unsigned long pos,
-				     void __user *src, unsigned long count)
+				     struct iov_iter *src, unsigned long count)
 {
 	struct snd_rme9652 *rme9652 = snd_pcm_substream_chip(substream);
 	signed char *channel_buf;
@@ -1857,30 +1857,14 @@ static int snd_rme9652_playback_copy(struct snd_pcm_substream *substream,
 						       channel);
 	if (snd_BUG_ON(!channel_buf))
 		return -EIO;
-	if (copy_from_user(channel_buf + pos, src, count))
+	if (copy_from_iter(channel_buf + pos, count, src) != count)
 		return -EFAULT;
 	return 0;
 }
 
-static int snd_rme9652_playback_copy_kernel(struct snd_pcm_substream *substream,
-					    int channel, unsigned long pos,
-					    void *src, unsigned long count)
-{
-	struct snd_rme9652 *rme9652 = snd_pcm_substream_chip(substream);
-	signed char *channel_buf;
-
-	channel_buf = rme9652_channel_buffer_location(rme9652,
-						      substream->pstr->stream,
-						      channel);
-	if (snd_BUG_ON(!channel_buf))
-		return -EIO;
-	memcpy(channel_buf + pos, src, count);
-	return 0;
-}
-
 static int snd_rme9652_capture_copy(struct snd_pcm_substream *substream,
 				    int channel, unsigned long pos,
-				    void __user *dst, unsigned long count)
+				    struct iov_iter *dst, unsigned long count)
 {
 	struct snd_rme9652 *rme9652 = snd_pcm_substream_chip(substream);
 	signed char *channel_buf;
@@ -1893,27 +1877,11 @@ static int snd_rme9652_capture_copy(struct snd_pcm_substream *substream,
 						       channel);
 	if (snd_BUG_ON(!channel_buf))
 		return -EIO;
-	if (copy_to_user(dst, channel_buf + pos, count))
+	if (copy_to_iter(channel_buf + pos, count, dst) != count)
 		return -EFAULT;
 	return 0;
 }
 
-static int snd_rme9652_capture_copy_kernel(struct snd_pcm_substream *substream,
-					   int channel, unsigned long pos,
-					   void *dst, unsigned long count)
-{
-	struct snd_rme9652 *rme9652 = snd_pcm_substream_chip(substream);
-	signed char *channel_buf;
-
-	channel_buf = rme9652_channel_buffer_location(rme9652,
-						      substream->pstr->stream,
-						      channel);
-	if (snd_BUG_ON(!channel_buf))
-		return -EIO;
-	memcpy(dst, channel_buf + pos, count);
-	return 0;
-}
-
 static int snd_rme9652_hw_silence(struct snd_pcm_substream *substream,
 				  int channel, unsigned long pos,
 				  unsigned long count)
@@ -2370,8 +2338,7 @@ static const struct snd_pcm_ops snd_rme9652_playback_ops = {
 	.prepare =	snd_rme9652_prepare,
 	.trigger =	snd_rme9652_trigger,
 	.pointer =	snd_rme9652_hw_pointer,
-	.copy_user =	snd_rme9652_playback_copy,
-	.copy_kernel =	snd_rme9652_playback_copy_kernel,
+	.copy =		snd_rme9652_playback_copy,
 	.fill_silence =	snd_rme9652_hw_silence,
 };
 
@@ -2383,8 +2350,7 @@ static const struct snd_pcm_ops snd_rme9652_capture_ops = {
 	.prepare =	snd_rme9652_prepare,
 	.trigger =	snd_rme9652_trigger,
 	.pointer =	snd_rme9652_hw_pointer,
-	.copy_user =	snd_rme9652_capture_copy,
-	.copy_kernel =	snd_rme9652_capture_copy_kernel,
+	.copy =		snd_rme9652_capture_copy,
 };
 
 static int snd_rme9652_create_pcm(struct snd_card *card,