ALSA: korg1212: Convert to generic PCM copy ops

This patch converts the korg1212 driver code to use the new unified
PCM copy callback.  The open-coded conditional memory copies are
replaced with simpler copy_from/to_iter() calls.

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

Link: https://lore.kernel.org/r/20230815190136.8987-9-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/korg1212/korg1212.c

@@ -1285,8 +1285,7 @@ static int snd_korg1212_silence(struct snd_korg1212 *korg1212, int pos, int coun
 }
 
 static int snd_korg1212_copy_to(struct snd_pcm_substream *substream,
-				void __user *dst, int pos, int count,
-				bool in_kernel)
+				struct iov_iter *dst, int pos, int count)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
         struct snd_korg1212 *korg1212 = snd_pcm_substream_chip(substream);
@@ -1306,24 +1305,20 @@ static int snd_korg1212_copy_to(struct snd_pcm_substream *substream,
 #if K1212_DEBUG_LEVEL > 0
 		if ( (void *) src < (void *) korg1212->recordDataBufsPtr ||
 		     (void *) src > (void *) korg1212->recordDataBufsPtr[8].bufferData ) {
-			printk(KERN_DEBUG "K1212_DEBUG: snd_korg1212_copy_to KERNEL EFAULT, src=%p dst=%p iter=%d\n", src, dst, i);
+			printk(KERN_DEBUG "K1212_DEBUG: snd_korg1212_copy_to KERNEL EFAULT, src=%p dst=%p iter=%d\n", src, dst->kvec.iov_base, i);
 			return -EFAULT;
 		}
 #endif
-		if (in_kernel)
-			memcpy((__force void *)dst, src, size);
-		else if (copy_to_user(dst, src, size))
+		if (copy_to_iter(src, size, dst) != size)
 			return -EFAULT;
 		src++;
-		dst += size;
 	}
 
 	return 0;
 }
 
 static int snd_korg1212_copy_from(struct snd_pcm_substream *substream,
-				  void __user *src, int pos, int count,
-				  bool in_kernel)
+				  struct iov_iter *src, int pos, int count)
 {
         struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_korg1212 *korg1212 = snd_pcm_substream_chip(substream);
@@ -1345,16 +1340,13 @@ static int snd_korg1212_copy_from(struct snd_pcm_substream *substream,
 #if K1212_DEBUG_LEVEL > 0
 		if ( (void *) dst < (void *) korg1212->playDataBufsPtr ||
 		     (void *) dst > (void *) korg1212->playDataBufsPtr[8].bufferData ) {
-			printk(KERN_DEBUG "K1212_DEBUG: snd_korg1212_copy_from KERNEL EFAULT, src=%p dst=%p iter=%d\n", src, dst, i);
+			printk(KERN_DEBUG "K1212_DEBUG: snd_korg1212_copy_from KERNEL EFAULT, src=%p dst=%p iter=%d\n", src->kvec.iov_base, dst, i);
 			return -EFAULT;
 		}
 #endif
-		if (in_kernel)
-			memcpy(dst, (__force void *)src, size);
-		else if (copy_from_user(dst, src, size))
+		if (copy_from_iter(dst, size, src) != size)
 			return -EFAULT;
 		dst++;
-		src += size;
 	}
 
 	return 0;
@@ -1642,17 +1634,9 @@ static snd_pcm_uframes_t snd_korg1212_capture_pointer(struct snd_pcm_substream *
 
 static int snd_korg1212_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)
 {
-	return snd_korg1212_copy_from(substream, src, pos, count, false);
-}
-
-static int snd_korg1212_playback_copy_kernel(struct snd_pcm_substream *substream,
-				      int channel, unsigned long pos,
-				      void *src, unsigned long count)
-{
-	return snd_korg1212_copy_from(substream, (void __user *)src,
-				      pos, count, true);
+	return snd_korg1212_copy_from(substream, src, pos, count);
 }
 
 static int snd_korg1212_playback_silence(struct snd_pcm_substream *substream,
@@ -1670,17 +1654,9 @@ static int snd_korg1212_playback_silence(struct snd_pcm_substream *substream,
 
 static int snd_korg1212_capture_copy(struct snd_pcm_substream *substream,
 				     int channel, unsigned long pos,
-				     void __user *dst, unsigned long count)
-{
-	return snd_korg1212_copy_to(substream, dst, pos, count, false);
-}
-
-static int snd_korg1212_capture_copy_kernel(struct snd_pcm_substream *substream,
-				     int channel, unsigned long pos,
-				     void *dst, unsigned long count)
+				     struct iov_iter *dst, unsigned long count)
 {
-	return snd_korg1212_copy_to(substream, (void __user *)dst,
-				    pos, count, true);
+	return snd_korg1212_copy_to(substream, dst, pos, count);
 }
 
 static const struct snd_pcm_ops snd_korg1212_playback_ops = {
@@ -1691,8 +1667,7 @@ static const struct snd_pcm_ops snd_korg1212_playback_ops = {
         .prepare =	snd_korg1212_prepare,
         .trigger =	snd_korg1212_trigger,
         .pointer =	snd_korg1212_playback_pointer,
-	.copy_user =	snd_korg1212_playback_copy,
-	.copy_kernel =	snd_korg1212_playback_copy_kernel,
+	.copy =		snd_korg1212_playback_copy,
 	.fill_silence =	snd_korg1212_playback_silence,
 };
 
@@ -1704,8 +1679,7 @@ static const struct snd_pcm_ops snd_korg1212_capture_ops = {
 	.prepare =	snd_korg1212_prepare,
 	.trigger =	snd_korg1212_trigger,
 	.pointer =	snd_korg1212_capture_pointer,
-	.copy_user =	snd_korg1212_capture_copy,
-	.copy_kernel =	snd_korg1212_capture_copy_kernel,
+	.copy =		snd_korg1212_capture_copy,
 };
 
 /*