From: Takashi Iwai <tiwai@suse.de>
Subject: ALSA: Backport snd_array_*() for HD-audio driver
Patch-mainline:
References: bnc#511306

Backport snd_array_*() from the recent kernel to update the
HD-audio driver code.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/pci/hda/hda_codec.c |   37 +++++++++++++++++++++++++++++++++++++
 sound/pci/hda/hda_codec.h |   30 ++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)

--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -3366,6 +3366,43 @@
 #endif
 
 /*
+ * generic arrays
+ */
+
+/* get a new element from the given array
+ * if it exceeds the pre-allocated array size, re-allocate the array
+ */
+void *snd_array_new(struct snd_array *array)
+{
+	if (array->used >= array->alloced) {
+		int num = array->alloced + array->alloc_align;
+		void *nlist;
+		if (num >= 4096)
+			return NULL;
+		nlist = kcalloc(num + 1, array->elem_size, GFP_KERNEL);
+		if (!nlist)
+			return NULL;
+		if (array->list) {
+			memcpy(nlist, array->list,
+			       array->elem_size * array->alloced);
+			kfree(array->list);
+		}
+		array->list = nlist;
+		array->alloced = num;
+	}
+	return snd_array_elem(array, array->used++);
+}
+
+/* free the given array elements */
+void snd_array_free(struct snd_array *array)
+{
+	kfree(array->list);
+	array->used = 0;
+	array->alloced = 0;
+	array->list = NULL;
+}
+
+/*
  * used by hda_proc.c and hda_eld.c
  */
 void snd_print_pcm_rates(int pcm, char *buf, int buflen)
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -520,6 +520,36 @@
 #define HDA_MAX_CODEC_ADDRESS	0x0f
 
 /*
+ * generic arrays
+ */
+struct snd_array {
+	unsigned int used;
+	unsigned int alloced;
+	unsigned int elem_size;
+	unsigned int alloc_align;
+	void *list;
+};
+
+void *snd_array_new(struct snd_array *array);
+void snd_array_free(struct snd_array *array);
+static inline void snd_array_init(struct snd_array *array, unsigned int size,
+				  unsigned int align)
+{
+	array->elem_size = size;
+	array->alloc_align = align;
+}
+
+static inline void *snd_array_elem(struct snd_array *array, unsigned int idx)
+{
+	return array->list + idx * array->elem_size;
+}
+
+static inline unsigned int snd_array_index(struct snd_array *array, void *ptr)
+{
+	return (unsigned long)(ptr - array->list) / array->elem_size;
+}
+
+/*
  * Structures
  */