ALSA: seq: Treat snd_seq_client object directly in client drivers

Introduce the new helpers, snd_seq_kernel_client_get() and _put() for
kernel client drivers to treat the snd_seq_client more directly.
This allows us to reduce the exported symbols and APIs at each time we
need to access some field in future.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-20-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Author: tiwai

sound/core/seq/seq_clientmgr.c

@@ -2390,6 +2390,21 @@ int snd_seq_kernel_client_write_poll(int clientid, struct file *file, poll_table
 }
 EXPORT_SYMBOL(snd_seq_kernel_client_write_poll);
 
+/* get a sequencer client object; for internal use from a kernel client */
+struct snd_seq_client *snd_seq_kernel_client_get(int id)
+{
+	return snd_seq_client_use_ptr(id);
+}
+EXPORT_SYMBOL_GPL(snd_seq_kernel_client_get);
+
+/* put a sequencer client object; for internal use from a kernel client */
+void snd_seq_kernel_client_put(struct snd_seq_client *cptr)
+{
+	if (cptr)
+		snd_seq_client_unlock(cptr);
+}
+EXPORT_SYMBOL_GPL(snd_seq_kernel_client_put);
+
 /*---------------------------------------------------------------------------*/
 
 #ifdef CONFIG_SND_PROC_FS

sound/core/seq/seq_clientmgr.h

@@ -88,4 +88,8 @@ void snd_seq_client_ioctl_unlock(int clientid);
 
 extern int seq_client_load[15];
 
+/* for internal use between kernel sequencer clients */
+struct snd_seq_client *snd_seq_kernel_client_get(int client);
+void snd_seq_kernel_client_put(struct snd_seq_client *cptr);
+
 #endif