ALSA: gus: Fix memory leaks at memory allocator error paths

When snd_gf1_mem_xalloc() returns NULL, the current code still leaves
the formerly allocated block.name string but returns an error
immediately. This patch does code-refactoring to move the kstrdup()
call itself into snd_gf1_mem_xalloc() and deals with the resource free
in the helper code by itself for fixing those memory leaks.

Suggested-by: Jaroslav Kysela <[e-mail]>
Reviewed-by: Jaroslav Kysela <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/isa/gus/gus_mem.c

···
 	}
 }
 
-static struct snd_gf1_mem_block *snd_gf1_mem_xalloc(struct snd_gf1_mem * alloc,
-					       struct snd_gf1_mem_block * block)
+static struct snd_gf1_mem_block *
+snd_gf1_mem_xalloc(struct snd_gf1_mem *alloc, struct snd_gf1_mem_block *block,
+		   const char *name)
 {
 	struct snd_gf1_mem_block *pblock, *nblock;
 
···
 	if (nblock == NULL)
 		return NULL;
 	*nblock = *block;
+	nblock->name = kstrdup(name, GFP_KERNEL);
+	if (!nblock->name) {
+		kfree(nblock);
+		return NULL;
+	}
+
 	pblock = alloc->first;
 	while (pblock) {
 		if (pblock->ptr > nblock->ptr) {
···
 	if (share_id != NULL)
 		memcpy(&block.share_id, share_id, sizeof(block.share_id));
 	block.owner = owner;
-	block.name = kstrdup(name, GFP_KERNEL);
-	if (block.name == NULL) {
-		snd_gf1_mem_lock(alloc, 1);
-		return NULL;
-	}
-	nblock = snd_gf1_mem_xalloc(alloc, &block);
+	nblock = snd_gf1_mem_xalloc(alloc, &block, name);
 	snd_gf1_mem_lock(alloc, 1);
 	return nblock;
 }
···
 	if (gus->gf1.enh_mode) {
 		block.ptr = 0;
 		block.size = 1024;
-		block.name = kstrdup("InterWave LFOs", GFP_KERNEL);
-		if (block.name == NULL || snd_gf1_mem_xalloc(alloc, &block) == NULL)
+		if (!snd_gf1_mem_xalloc(alloc, &block, "InterWave LFOs"))
 			return -ENOMEM;
 	}
 	block.ptr = gus->gf1.default_voice_address;
 	block.size = 4;
-	block.name = kstrdup("Voice default (NULL's)", GFP_KERNEL);
-	if (block.name == NULL || snd_gf1_mem_xalloc(alloc, &block) == NULL)
+	if (!snd_gf1_mem_xalloc(alloc, &block, "Voice default (NULL's)"))
 		return -ENOMEM;
 #ifdef CONFIG_SND_DEBUG
 	snd_card_ro_proc_new(gus->card, "gusmem", gus, snd_gf1_mem_info_read);