ALSA: pcm: refactor copy from/to user in SNDRV_PCM_IOCTL_SYNC_PTR

In an effort of optimising SNDRV_PCM_IOCTL_SYNC_PTR ioctl which
is a hot path, lets first refactor the copy from and to user
with macros.

This is done with macros and not static inline fonctions because
types differs between the different versions of snd_pcm_sync_ptr()
like functions.

First step is to refactor only snd_pcm_ioctl_sync_ptr_compat() and
snd_pcm_ioctl_sync_ptr_x32() as it would be a performance
regression for snd_pcm_sync_ptr() and snd_pcm_ioctl_sync_ptr_buggy()
for now. They may be refactored after next patch.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/f8b77932bb9ce96148ae5c3953e7ee44fa2359f8.1749883041.git.christophe.leroy@csgroup.eu

Author: chleroy

sound/core/pcm_compat.c

@@ -418,9 +418,7 @@ static int snd_pcm_ioctl_sync_ptr_x32(struct snd_pcm_substream *substream,
 	if (snd_BUG_ON(!runtime))
 		return -EINVAL;
 
-	if (get_user(sflags, &src->flags) ||
-	    get_user(scontrol.appl_ptr, &src->c.control.appl_ptr) ||
-	    get_user(scontrol.avail_min, &src->c.control.avail_min))
+	if (snd_pcm_sync_ptr_get_user(sflags, scontrol, src))
 		return -EFAULT;
 	if (sflags & SNDRV_PCM_SYNC_PTR_HWSYNC) {
 		err = snd_pcm_hwsync(substream);
@@ -450,15 +448,7 @@ static int snd_pcm_ioctl_sync_ptr_x32(struct snd_pcm_substream *substream,
 	}
 	if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
 		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
-	if (put_user(sstatus.state, &src->s.status.state) ||
-	    put_user(sstatus.hw_ptr, &src->s.status.hw_ptr) ||
-	    put_user(sstatus.tstamp.tv_sec, &src->s.status.tstamp_sec) ||
-	    put_user(sstatus.tstamp.tv_nsec, &src->s.status.tstamp_nsec) ||
-	    put_user(sstatus.suspended_state, &src->s.status.suspended_state) ||
-	    put_user(sstatus.audio_tstamp.tv_sec, &src->s.status.audio_tstamp_sec) ||
-	    put_user(sstatus.audio_tstamp.tv_nsec, &src->s.status.audio_tstamp_nsec) ||
-	    put_user(scontrol.appl_ptr, &src->c.control.appl_ptr) ||
-	    put_user(scontrol.avail_min, &src->c.control.avail_min))
+	if (snd_pcm_sync_ptr_put_user(sstatus, scontrol, src))
 		return -EFAULT;
 
 	return 0;

sound/core/pcm_native.c

@@ -3052,6 +3052,34 @@ static inline int snd_pcm_hwsync(struct snd_pcm_substream *substream)
 	return snd_pcm_delay(substream, NULL);
 }
 
+#define snd_pcm_sync_ptr_get_user(__f, __c, __ptr) ({				\
+	int __err = 0;								\
+	typeof(*(__ptr)) __user *__src = (__ptr);				\
+										\
+	if (get_user(__f, &src->flags) ||					\
+	    get_user(__c.appl_ptr, &__src->c.control.appl_ptr) ||		\
+	    get_user(__c.avail_min, &__src->c.control.avail_min))		\
+		__err = -EFAULT;						\
+	__err;									\
+})
+
+#define snd_pcm_sync_ptr_put_user(__s, __c, __ptr) ({				\
+	int __err = 0;								\
+	typeof(*(__ptr)) __user *__src = (__ptr);				\
+										\
+	if (put_user(__s.state, &__src->s.status.state) ||			\
+	    put_user(__s.hw_ptr, &__src->s.status.hw_ptr) ||			\
+	    put_user(__s.tstamp.tv_sec, &__src->s.status.tstamp_sec) ||		\
+	    put_user(__s.tstamp.tv_nsec, &__src->s.status.tstamp_nsec) ||	\
+	    put_user(__s.suspended_state, &__src->s.status.suspended_state) ||	\
+	    put_user(__s.audio_tstamp.tv_sec, &__src->s.status.audio_tstamp_sec) ||	\
+	    put_user(__s.audio_tstamp.tv_nsec, &__src->s.status.audio_tstamp_nsec) ||	\
+	    put_user(__c.appl_ptr, &__src->c.control.appl_ptr) ||		\
+	    put_user(__c.avail_min, &__src->c.control.avail_min))		\
+		__err = -EFAULT;						\
+	__err;									\
+})
+
 static int snd_pcm_sync_ptr(struct snd_pcm_substream *substream,
 			    struct snd_pcm_sync_ptr __user *_sync_ptr)
 {
@@ -3165,9 +3193,7 @@ static int snd_pcm_ioctl_sync_ptr_compat(struct snd_pcm_substream *substream,
 	if (snd_BUG_ON(!runtime))
 		return -EINVAL;
 
-	if (get_user(sflags, &src->flags) ||
-	    get_user(scontrol.appl_ptr, &src->c.control.appl_ptr) ||
-	    get_user(scontrol.avail_min, &src->c.control.avail_min))
+	if (snd_pcm_sync_ptr_get_user(sflags, scontrol, src))
 		return -EFAULT;
 	if (sflags & SNDRV_PCM_SYNC_PTR_HWSYNC) {
 		err = snd_pcm_hwsync(substream);
@@ -3200,15 +3226,7 @@ static int snd_pcm_ioctl_sync_ptr_compat(struct snd_pcm_substream *substream,
 	}
 	if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
 		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
-	if (put_user(sstatus.state, &src->s.status.state) ||
-	    put_user(sstatus.hw_ptr, &src->s.status.hw_ptr) ||
-	    put_user(sstatus.tstamp.tv_sec, &src->s.status.tstamp_sec) ||
-	    put_user(sstatus.tstamp.tv_nsec, &src->s.status.tstamp_nsec) ||
-	    put_user(sstatus.suspended_state, &src->s.status.suspended_state) ||
-	    put_user(sstatus.audio_tstamp.tv_sec, &src->s.status.audio_tstamp_sec) ||
-	    put_user(sstatus.audio_tstamp.tv_nsec, &src->s.status.audio_tstamp_nsec) ||
-	    put_user(scontrol.appl_ptr, &src->c.control.appl_ptr) ||
-	    put_user(scontrol.avail_min, &src->c.control.avail_min))
+	if (snd_pcm_sync_ptr_put_user(sstatus, scontrol, src))
 		return -EFAULT;
 
 	return 0;